text:
User:Michael d allen/MOSE

= Michael's OpenSCAD Extensions =

Investigating integrating my extensions with OpenSCAD doc.

If this is any sort of copyright/IP infringement - sorry. Let me know and I'll take it down

Extended from OpenSCAD_User_Manual/Primitive_Solids (2022.12.21).

Page comparison here

chamfer

Estalishes a 45 degree relief on an object's outside corners.

(chamfer = 0)

 * parameters:
 * chamfer
 * depth of chamfer, as measure by the length of the legs [Right Triangle]

default values: (chamfer omitted)   yields:  chamfer of 0, or no chamfer

center
Align an object. center has an additional behavior in addition to the standard OpenSCAD [cube]) behavior.

Specifying center as a array[3] will move the object into the corresponding octant(s). An assignment of center = [0,0,0] is equivalent to center = true (center the object), center = [1, 1, 1] is equivalent to center = false (position the object in the first octant), and center = [-1, -1, -1] positions the object in the eighth octant.

The values -1, 0, and 1 result in the intuitive left/front/bottom, center, right/back/top alignment of the object. While the values -1, 0, and 1 are the most intuitive, any values are acceptable. The object will be shifted along it's given axis by an amount equal to half that object's extent in that axis multiplied by the center[] value for that axis.

(center = bool| array[3])

 * parameters:
 * center
 * single boolean value as explained here [cube]
 * 3 value array [x,y,z] specifying alignment for each axis

default values: (center omitted)   yields:  equivalent of center = false, positioning the object in the first octant.

 * example:

 * See: https://en.wikibooks.org/wiki/User:Michael_d_allen/MOSE#mcube

color
See: https://en.wikibooks.org/wiki/OpenSCAD_User_Manual/Transformations#color

manifold_overlap
Add 0.01 unit to all outside dimensions. This may eliminate rendering artifacts that result from exactly adjacent objects.

(manifold_overlap = bool)

 * parameters:
 * manifold_overlap
 * boolean

default value: false

mcube
OpenSCAD cube with
 * extended center option - https://en.wikibooks.org/wiki/User:Michael_d_allen/MOSE#center
 * optional chamfer option - https://en.wikibooks.org/wiki/User:Michael_d_allen/MOSE#chamfer
 * optional color option - https://en.wikibooks.org/wiki/User:Michael_d_allen/MOSE#color

Creates a cube in the first octant. When center is true, the cube is centered on the origin. Argument names are optional if given in the order shown here.

mcube(size = [x,y,z], center = true/false/[x,y,z][, chamfer = c][, color = rgb]); mcube(size = x,     center = true/false/[x,y,z][, chamfer = c][, color = rgb]);

 * example:

mcube( 5,         true, chamfer = 1  , color =  "green"); color("pink")  mcube(  6                                                ); mcube( 5, [-1, -1, -1], chamfer = 1  , color = "orange"); mcube(4.5,        true, chamfer = 0.25                  );

cube
Creates a cube in the first octant. When center is true, the cube is centered on the origin. Argument names are optional if given in the order shown here. cube(size = [x,y,z], center = true/false); cube(size = x,     center = true/false);

 *  parameters:

 * size
 * single value, cube with all sides this length
 * 3 value array [x,y,z], cube with dimensions x, y and z.
 * center
 * false (default), 1st (positive) octant, one corner at (0,0,0)
 * true, cube is centered at (0,0,0)

default values: cube;   yields:  cube(size = [1, 1, 1], center = false);
 *  examples:

equivalent scripts for this example cube(size = 18); cube(18); cube([18,18,18]); . cube(18,false); cube([18,18,18],false); cube([18,18,18],center=false); cube(size = [18,18,18], center = false); cube(center = false,size = [18,18,18] );

equivalent scripts for this example cube([18,28,8],true); box=[18,28,8];cube(box,true);

sphere
Creates a sphere at the origin of the coordinate system. The r argument name is optional. To use d instead of r, d must be named.

Parameters

default values: sphere;   yields:   sphere($fn = 0, $fa = 12, $fs = 2, r = 1);
 * r : Radius. This is the radius of the sphere.  The resolution of the sphere is based on the size of the sphere and the $fa, $fs and $fn variables. For more information on these special variables look at: OpenSCAD_User_Manual/Other_Language_Features
 * d : Diameter. This is the diameter of the sphere.
 * $fa : Fragment angle in degrees
 * $fs : Fragment size in mm
 * $fn : Resolution

Usage Examples sphere(r = 1); sphere(r = 5); sphere(r = 10); sphere(d = 2); sphere(d = 10); sphere(d = 20);

// this creates a high resolution sphere with a 2mm radius sphere(2, $fn=100);

// also creates a 2mm high resolution sphere but this one // does not have as many small triangles on the poles of the sphere sphere(2, $fa=5, $fs=0.1);

cylinder
Creates a cylinder or cone centered about the z axis. When center is true, it is also centered vertically along the z axis.

Parameter names are optional if given in the order shown here. If a parameter is named, all following parameters must also be named.

cylinder(h = height, r1 = BottomRadius, r2 = TopRadius, center = true/false);

NOTES:

The 2nd & 3rd positional parameters are r1 & r2, if r, d, d1 or d2 are used they must be named.

Using r1 & r2 or d1 & d2 with either value of zero will make a cone shape, a non-zero non-equal value will produce a section of a cone (a Conical Frustum). r1 & d1 define the base width, at [0,0,0], and r2 & d2 define the top width.
 * Parameters

 * h : height of the cylinder or cone
 * r  : radius of cylinder. r1 = r2 = r.
 * r1 : radius, bottom of cone.
 * r2 : radius, top of cone.
 * d  : diameter of cylinder. r1 = r2 = d / 2.
 * d1 : diameter, bottom of cone. r1 = d1 / 2.
 * d2 : diameter, top of cone. r2 = d2 / 2.
 * center
 * false (default), z ranges from 0 to h
 * true, z ranges from -h/2 to +h/2
 * $fa : minimum angle (in degrees) of each fragment.
 * $fs : minimum circumferential length of each fragment.
 * $fn : fixed number of fragments in 360 degrees. Values of 3 or more override $fa and $fs
 * $fa, $fs and $fn must be named parameters. click here for more details,.

defaults: cylinder; yields: cylinder($fn = 0, $fa = 12, $fs = 2, h = 1, r1 = 1, r2 = 1, center = false);

equivalent scripts cylinder(h=15, r1=9.5, r2=19.5, center=false); cylinder( 15,    9.5,    19.5, false); cylinder( 15,    9.5,    19.5); cylinder( 15,    9.5, d2=39  ); cylinder( 15, d1=19,  d2=39  ); cylinder( 15, d1=19,  r2=19.5);

equivalent scripts cylinder(h=15, r1=10, r2=0, center=true); cylinder( 15,    10,    0,        true); cylinder(h=15, d1=20, d2=0, center=true);

script for this example poly_n = 6; color("blue") translate([0, 0, 0.02]) linear_extrude(0.1) circle(10, $fn=poly_n); color("green") translate([0, 0, 0.01]) linear_extrude(0.1) circle(10, $fn=360); color("purple") linear_extrude(0.1) circle(10/cos(180/poly_n), $fn=poly_n);

In general, a polygon of radius $$r$$ has a radius to the midpoint of any side as $$r_m = r \cos(180/n)$$. If only the midpoint radius $$r_m$$ is known (for example, to fit a hex key into a hexagonal hole), then the polygon radius is $$r = \frac{r_m}{\cos(180/n)}$$.

polyhedron
A polyhedron is the most general 3D primitive solid. It can be used to create any regular or irregular shape including those with concave as well as convex features. Curved surfaces are approximated by a series of flat surfaces.

polyhedron( points = [ [X0, Y0, Z0], [X1, Y1, Z1], ... ], triangles = [ [P0, P1, P2], ... ], convexity = N);  // before 2014.03 polyhedron( points = [ [X0, Y0, Z0], [X1, Y1, Z1], ... ], faces = [ [P0, P1, P2, P3, ...], ... ], convexity = N);  // 2014.03 & later

 * Parameters
 * points
 * Vector of 3d points or vertices. Each point is in turn a vector, [x,y,z], of its coordinates.
 * Points may be defined in any order. N points are referenced, in the order defined, as 0 to N-1.

 * triangles
 * Vector of faces that collectively enclose the solid. Each face is a vector containing the indices (0 based) of 3 points from the points vector.

 * faces
 * Vector of faces that collectively enclose the solid. Each face is a vector containing the indices (0 based) of 3 or more points from the points vector.
 * Faces may be defined in any order. Define enough faces to fully enclose the solid, with no overlap.
 * If points that describe a single face are not on the same plane, the face is automatically split into triangles as needed.

 * convexity
 * Integer. The convexity parameter specifies the maximum number of faces a ray intersecting the object might penetrate. This parameter is needed only for correct display of the object in OpenCSG preview mode. It has no effect on the polyhedron rendering. For display problems, setting it to 10 should work fine for most cases.

default values: polyhedron; yields: polyhedron(points = undef, faces = undef, convexity = 1);

It is arbitrary which point you start with, but all faces must have points ordered in clockwise direction when looking at each face from outside inward. The back is viewed from the back, the bottom from the bottom, etc. Another way to remember this ordering requirement is to use the right-hand rule. Using your right-hand, stick your thumb up and curl your fingers as if giving the thumbs-up sign, point your thumb into the face, and order the points in the direction your fingers curl. Try this on the example below.

 * Example 1 Using polyhedron to generate cube( [ 10, 7, 5 ] );

CubePoints = [ [ 0,  0,  0 ],  //0   [ 10,  0,  0 ],  //1   [ 10,  7,  0 ],  //2   [  0,  7,  0 ],  //3   [  0,  0,  5 ],  //4   [ 10,  0,  5 ],  //5   [ 10,  7,  5 ],  //6   [  0,  7,  5 ]]; //7 CubeFaces = [ [0,1,2,3], // bottom [4,5,1,0], // front [7,6,5,4], // top [5,6,2,1], // right [6,7,3,2], // back [7,4,0,3]]; // left polyhedron( CubePoints, CubeFaces );

equivalent descriptions of the bottom face [0,1,2,3],  [0,1,2,3,0],   [1,2,3,0],   [2,3,0,1],   [3,0,1,2],   [0,1,2],[2,3,0],   // 2 triangles with no overlap [1,2,3],[3,0,1],  [1,2,3],[0,1,3],
 * Example 2 A square base pyramid:

polyhedron(  points=[ [10,10,0],[10,-10,0],[-10,-10,0],[-10,10,0], // the four points at base            [0,0,10]  ],                                 // the apex point    faces=[ [0,1,4],[1,2,4],[2,3,4],[3,0,4],              // each triangle side               [1,0,3],[2,1,3] ]                         // two triangles for square base  );
 * Example 3 A triangular prism:

Note: There is an error in this example, a steely-eyed CAD Man noticed the unfolded triangles are incorrect, the hypotenuse should be 1,5 & 0,4. The correct unfold is to have them next to rectangle A, along sides 1,2 & 0,3. The code has been corrected, hopefully a revised image will arrive in due course.

module prism(l, w, h){ polyhedron(//pt 0       1        2        3        4        5               points=0,0,0], [l,0,0], [l,w,0], [0,w,0], [0,w,h], [l,w,h,               faces=0,1,2,3],[5,4,3,2],[0,4,5,1],[0,3,4],[5,2,1               ); // preview unfolded (do not include in your function      z = 0.08;       separation = 2;       border = .2;       translate([0,w+separation,0])           cube([l,w,z]);       translate([0,w+separation+w+border,0])           cube([l,h,z]);       translate([0,w+separation+w+border+h+border,0])           cube([l,sqrt(w*w+h*h),z]);       translate([l+border,w+separation,0])           polyhedron(//pt 0       1       2        3       4       5 points=0,0,0],[h,w,0],[0,w,0], [0,0,z],[h,w,z],[0,w,z, faces=0,1,2], [3,5,4], [0,3,4,1], [1,4,5,2], [2,5,3,0 );      translate([0-border,w+separation,0])           polyhedron(//pt 0       1         2        3       4         5 points=0,0,0],[0-h,w,0],[0,w,0], [0,0,z],[0-h,w,z],[0,w,z, faces=1,0,2],[5,3,4],[0,1,4,3],[1,2,5,4],[2,0,3,5 );      }   prism(10, 5, 3);

Debugging polyhedra
Mistakes in defining polyhedra include not having all faces in clockwise order (viewed from outside - a bottom need to be viewed from below), overlap of faces and missing faces or portions of faces. As a general rule, the polyhedron faces should also satisfy manifold conditions: The first rule eliminates polyhedra like two cubes with a common edge and not watertight models; the second excludes polyhedra like two cubes with a common vertex.
 * exactly two faces should meet at any polyhedron edge.
 * if two faces have a vertex in common, they should be in the same cycle face-edge around the vertex.

When viewed from the outside, the points describing each face must be in the same clockwise order, and provides a mechanism for detecting counterclockwise. When the thrown together view (F12) is used with F5, CCW faces are shown in pink. Reorder the points for incorrect faces. Rotate the object to view all faces. The pink view can be turned off with F10.

OpenSCAD allows, temporarily, commenting out part of the face descriptions so that only the remaining faces are displayed. Use // to comment out the rest of the line. Use /* and */ to start and end a comment block. This can be part of a line or extend over several lines. Viewing only part of the faces can be helpful in determining the right points for an individual face. Note that a solid is not shown, only the faces. If using F12, all faces have one pink side. Commenting some faces helps also to show any internal face.

CubeFaces = [ /* [0,1,2,3], // bottom [4,5,1,0], // front */ [7,6,5,4], // top /* [5,6,2,1], // right [6,7,3,2], // back */ [7,4,0,3]]; // left

After defining a polyhedron, its preview may seem correct. The polyhedron alone may even render fine. However, to be sure it is a valid manifold and that it can generate a valid STL file, union it with any cube and render it (F6). If the polyhedron disappears, it means that it is not correct. Revise the winding order of all faces and the two rules stated above.

Mis-ordered faces

 * Example 4 a more complex polyhedron with mis-ordered faces

When you select 'Thrown together' from the view menu and compile (preview F5) the design (not compile and render!) the preview shows the mis-oriented polygons highlighted. Unfortunately this highlighting is not possible in the OpenCSG preview mode because it would interfere with the way the OpenCSG preview mode is implemented.)

Below you can see the code and the picture of such a problematic polyhedron, the bad polygons (faces or compositions of faces) are in pink.

A correct polyhedron would be the following:

 * Beginner's tip:

If you don't really understand "orientation", try to identify the mis-oriented pink faces and then invert the sequence of the references to the points vectors until you get it right. E.g. in the above example, the third triangle ([0,4,5]) was wrong and we fixed it as [4,0,5]. Remember that a face list is a circular list. In addition, you may select "Show Edges" from the "View Menu", print a screen capture and number both the points and the faces. In our example, the points are annotated in black and the faces in blue. Turn the object around and make a second copy from the back if needed. This way you can keep track.

 * Clockwise Technique:

Orientation is determined by clockwise circular indexing. This means that if you're looking at the triangle (in this case [4,0,5]) from the outside you'll see that the path is clockwise around the center of the face. The winding order [4,0,5] is clockwise and therefore good. The winding order [0,4,5] is counter-clockwise and therefore bad. Likewise, any other clockwise order of [4,0,5] works: [5,4,0] & [0,5,4] are good too. If you use the clockwise technique, you'll always have your faces outside (outside of OpenSCAD, other programs do use counter-clockwise as the outside though).

Think of it as a Left Hand Rule:

If you place your left hand on the face with your fingers curled in the direction of the order of the points, your thumb should point outward. If your thumb points inward, you need to reverse the winding order.

Succinct description of a 'Polyhedron'

* Points define all of the points/vertices in the shape. * Faces is a list of flat polygons that connect up the points/vertices.

Each point, in the point list, is defined with a 3-tuple x,y,z position specification. Points in the point list are automatically enumerated starting from zero for use in the faces list (0,1,2,3,... etc).

Each face, in the faces list, is defined by selecting 3 or more of the points (using the point order number) out of the point list.

e.g. faces=[ [0,1,2] ] defines a triangle from the first point (points are zero referenced) to the second point and then to the third point.

When looking at any face from the outside, the face must list all points in a clockwise order.

Point repetitions in a polyhedron point list
The point list of the polyhedron definition may have repetitions. When two or more points have the same coordinates they are considered the same polyhedron vertex. So, the following polyhedron:

define the same tetrahedron as:

OpenSCAD/Primitive_solidi Руководство_пользователя_по_OpenSCAD/Примитивы_объемных_тел

title: User:Michael d allen/MOSE


text:
User:Gabriella Wade/sandbox

User:GabriellaWade/sandbox

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: User:Gabriella Wade/sandbox


text:
The University of 2050

The University of 2050 is a vision of the university as it can and should be in 2050. It is written by uniquely qualified authors: the students of the university of the 2020s, many of whom will raise the people who may become the students of the university of the 2050s. This connection gives these authors a direct stake in the success of the university of 2050. The university of the 2020s remains much like its predecessor of 25 or 50 years ago. The campus, the classroom, and the curriculum of the 1990s or even of the 1970s endure much as they were. This endurance may be due largely to the efficacy of these arrangements, or it may be due to a paucity of visionary, long-term planning. If the university of 2050 is to be more affordable, inclusive and sustainable than the university of the 2020s, the planning must begin now. The authors themselves determine the educational ideas and values that the university of 2050 will serve. They will also consider how the technology of the mid-21st century may permit new educational possibilities, and which university traditions of decades and centuries past should endure.

The University of 2050 is divided into three parts: 1. The campus of 2050 2. The classroom of 2050 3. The curriculum of 2050

Within each section, chapters will consider more specific subsets of these subjects. Authors are invented to consider each of them broadly, without regard in inherited assumptions. For example, the classroom of 2050 need not be a physical room at all, or may include a room and more besides.

The Campus of 2050

 * /The Sustainable Campus/
 * /Campus Mobility and Community Connections/
 * /The Globally Connected Campus/

The Classroom of 2050

 * /The Transphysical Classroom/
 * /The Adaptable Classroom/
 * /The Experiential Classroom/

The Curriculum of 2050

 * /Welcoming Curricular Innovation/
 * /Personalizing Curricula/
 * /The Future of the Humanities/

title: The University of 2050


text:
History of video games/Platforms/VILROS Retro Gaming Kit

Technology
The system was designed for use with a Raspberry Pi 3 Model B+.


text:
Engineering Education in 2050

Engineering Education in 2050 is a vision of the engineering education, including computer science, as it can and should be in 2050. It is written by uniquely qualified authors: engineering students of the 2020s, many of whom will raise the people who may become the engineering students of of the 2050s. The authors have years personal experience in their subject. This connection gives these authors a direct stake in the success of the engineering education of 2050. Engineering education in the 2020s remains much like its predecessor of 25 or 50 years ago. Students still study textbooks, attended lectures in classrooms, do problem sets, and take tests, much as their predecessors did in the classrooms of the 1990s or even of the 1970s. This endurance may be due largely to the efficacy of these arrangements, or it may be due to a paucity of visionary, long-term planning. If the engineering education of 2050 is to be better than the engineering education of the 2020s, the planning must begin now. The authors themselves determine the educational ideas and values that engineering education in 2050 will serve. They will also consider how the technology of the mid-21st century may permit new educational possibilities, and which educational techniques of decades and centuries past should endure.

Engineering Education in 2050 is divided into three parts: 1. Beyond Desks, Textbooks, Problem Sets, and Tests 2. Beyond Ages 18-22 3. Beyond Truncated Innovation

Within each section, chapters will consider more specific subsets of these subjects. Authors are invented to consider each of them broadly, without regard in inherited assumptions.

Beyond Textbooks, Problem Sets, and Tests

 * /Learning Engineering by Engineering/
 * /Engineering as Applied Creativity/
 * /Professional Relationship Building/

Full-Spectrum Innovation

 * /High-Sōsh Techniques/
 * /Engineers as Applied Social Scientists/
 * /Tools, Not Just Solutions/

The Future of Computer Science Education

 * /Post-Classroom CS/
 * /CS for Sustainability/
 * /Keeping Humans in Responsible Charge of AI/

title: Engineering Education in 2050


text:
Mobility 2050

Mobility 2050 is a vision of everyday personal mobility as it can and should be in 2050. It is written by uniquely qualified authors: engineering students who have the technical education they need to conceive of, review, and evaluate sociotechnical alternatives in mobility, but who – unlike many people of comparable qualifications – are also young enough to expect to be working citizens in the future they write about, perhaps with decades still ahead of them. These qualifications give these authors a direct, personal stake in the success of mobility visions they propose.

Especially in the US, mobility policies and practices in the 2020s remain much as they were 25 or 50 years ago. Passenger transport, land use policies and practices, and transportation engineering standards have changed little since the 1990s and even the 1970s. At 29 percent, the share of total greenhouse gas emissions attributable to transportation in the US is higher than the share of any other major sector of the national economy, and higher than in other high-income nations. The endurance of such policies and practices may be due in part to a paucity of visionary, long-term planning.

If the mobility of 2050 in the United States is to be more affordable, inclusive and sustainable than the mobility of the 2020s, the planning must begin now. The authors themselves determine the ideas and values that the mobility of 2050 will serve. They will also consider how the technology of the mid-21st century may permit new mobility possibilities.

Mobility 2050 is divided into three parts: 1. Normalizing Walking and Micromobility 2. Making Transit Practical 3. Land Use Planning and Urban Design for Inclusive Sustainability

Within each section, chapters will consider more specific subsets of these subjects. Authors are invented to consider each of them broadly, without regard in inherited assumptions.

Normalizing Walking and Micromobility

 * /Learning from Success Stories/
 * /Lightweight Electromobility/
 * /Tech's Place in Micromobility/

Making Rail and Transit Practical

 * /New Transit Modes/
 * /Battery-Free Electromobility/
 * /Trains Instead of Planes/

Land Use Planning and Urban Design for Inclusive Sustainability

 * /The Future of the 15-Minute City/
 * /Recovering Land Lost to Parking Craters/
 * /Retrofitting Parking Garages/
 * /Retrofitting Suburbia/

title: Mobility 2050


text:
AI Art Generation Handbook/Differing Resolution for SDXL

This page is to showcase how does the differing resolutions can bring different results to Stable Diffusion,

Take note that all of the images uses the same settings with only differs is the resolution of image generated.

 Note 1: All images are resized to same square sizes, you can double click on each image to see it is differing sizes for each images

Prompt : Photo of a beautiful girl dancing

Sampling Method : DPM++ 2M Karras

Sampling Steps : 30

Seeds : 1305844618 Prompt : Sportscar Aston Martin Speedster racing on racetrack in countryside

Sampling Method : DPM++ 2M Karras

Sampling Steps : 30

Seeds : 2725987692


text: User talk:2402:7500:4E6:B897:45CF:B772:F11A:94FD


text:
Internal Medicine/Approach to Skin Disorders

Introduction
The challenge of examining the skin

Skin examination is a complex process involving the observation and analysis of the skin's surface. This task presents several challenges, including the need to differentiate between normal and abnormal findings, distinguish significant from trivial observations, and integrate these findings into a meaningful diagnostic framework. Essentially, skin examination is a crucial aspect of clinical practice, as it provides valuable insights into a patient's health.

Visibility of the largest organ

One unique aspect of skin examination is that it involves the largest organ in the human body—the skin itself. The skin's accessibility offers both advantages and disadvantages to clinicians. On one hand, it doesn't require specialized equipment or invasive procedures, making it relatively straightforward to examine. On the other hand, the surface area of the skin is extensive, and the sheer variety of possible skin conditions can be overwhelming.

Complexity of skin examination

Skin examination becomes particularly challenging due to the potential for variability in skin conditions. Sometimes, even minor variations in color, texture, or shape can be significant indicators of underlying skin or systemic diseases. For example, distinguishing between a benign nevomelanocytic nevus and a potentially malignant melanoma can be a nuanced process, requiring a trained eye.

Use of descriptive terms

To aid in the interpretation of cutaneous lesions and formulate a differential diagnosis, dermatologists and healthcare professionals have developed a wide range of descriptive terms. These terms help standardize the language used to describe skin conditions. For instance, the presence of scaling papules is characteristic of conditions like psoriasis or atopic dermatitis, whereas hemorrhagic papules may suggest vasculitis or sepsis.

Approach to the Patient
Assessing the patient before history

A systematic approach to skin examination typically involves assessing the patient's skin before delving into an extensive medical history. This method ensures that the entire surface area of the skin is thoroughly evaluated before any potential biases from historical information are introduced. Objective findings from the examination can then be correlated with relevant patient history.

Four basic features

A comprehensive skin examination relies on the observation and documentation of four basic features of skin issues:

 * 1) Distribution: Examining where on the body the skin lesions are located. This is often a critical clue for diagnosis. For instance, a generalized rash might suggest a systemic condition, while a rash localized to sun-exposed areas could indicate a different cause.
 * 2) Types of Primary and Secondary Lesions: Identifying the primary lesion (the initial skin change) and any secondary changes that have occurred as a result. Secondary changes include crust, scale, erosion, ulceration, or excoriation.
 * 3) Shape of Individual Lesions: Observing the shape and configuration of individual lesions. Some conditions present with specific lesion shapes, such as target-shaped lesions in erythema multiforme.
 * 4) Arrangement of Lesions: Understanding how the lesions are arranged in relation to each other. For example, linear arrangements may suggest external factors like contact dermatitis.

Comprehensive skin examination

A thorough skin examination encompasses more than just the skin's surface. It includes evaluating not only the skin itself but also the hair, nails, and mucous membranes. This comprehensive approach is essential because skin conditions can manifest in various ways across these different components. For example, certain skin conditions may affect both the skin and nails, providing crucial diagnostic clues.

Importance of distribution

Distribution is a key element in skin examination. The location of skin lesions can often provide valuable diagnostic insights. For instance, a patient with a generalized erythematous exanthem (widespread skin rash) is more likely to have a drug eruption when compared to a patient with a similar rash limited to specific areas of the face exposed to sunlight.

Distinguishing by primary lesion

Once the distribution of skin lesions is established, the next step involves determining the nature of the primary lesion. Primary skin lesions are the initial morphological changes in the skin that result from the disease process. Identifying the primary lesion is crucial in narrowing down potential diagnoses. For instance, if a patient presents with lesions on the elbows, knees, and scalp, the primary lesion's nature may point towards psoriasis or dermatitis herpetiformis.

Secondary changes in skin

In addition to primary lesions, healthcare professionals also pay close attention to secondary changes in the skin. These changes often occur as a result of the disease process or due to the patient's actions, such as scratching. Common secondary changes include the presence of scale (indicating excessive epidermal growth) or crust (resulting from a discontinuous epithelial cell layer). Recognizing these secondary changes can help refine the diagnosis further.

Palpation of skin lesions

Palpation, or the act of feeling the skin lesions, plays a critical role in skin examination. By gently pressing on or feeling the lesions, healthcare providers can gain additional information about their characteristics. For example, red papules on the lower extremities that blanch (become pale) when pressure is applied can be associated with various diseases. However, hemorrhagic red papules that do not blanch with pressure suggest palpable purpura, a distinctive feature of necrotizing vasculitis.

Shape and arrangement of lesions

The shape of individual lesions and their arrangement are essential aspects of skin examination. Identifying specific lesion shapes can be highly indicative of particular skin conditions. For instance, flat, round, erythematous papules and plaques are common in many skin diseases. However, target-shaped lesions that consist of erythematous plaques surrounded by a paler ring are specific to erythema multiforme.

Importance of arrangement

Furthermore, the arrangement of lesions provides valuable diagnostic clues. Lesions arranged in specific patterns, such as linear or grouped configurations, can suggest certain causes. For instance, erythematous papules and vesicles arranged linearly may indicate an external cause like allergic contact dermatitis, where the skin reacts to a specific allergen in a linear pattern. In contrast, generalized arrangements of lesions often point towards systemic conditions.

Diagnostic Techniques
Diagnosing skin diseases

While many skin diseases can be identified based on their clinical appearance, there are instances where diagnostic procedures are necessary to confirm or clarify a diagnosis. These diagnostic techniques are often straightforward and can be performed at the patient's bedside with minimal equipment.

Skin Biopsy
A straightforward procedure

Skin biopsy is a minor surgical procedure commonly used to obtain a tissue sample for diagnostic purposes. However, it's essential to choose the right lesion for biopsy to maximize the chances of obtaining diagnostic information. The decision on which lesion to biopsy may require expertise in dermatology and an understanding of superficial anatomical structures in specific areas of the body.

KOH Preparation
Detecting fungal infections

A potassium hydroxide (KOH) preparation is a diagnostic technique used when a fungal infection is suspected, particularly in cases involving scaling skin lesions. The procedure involves gently scraping the edge of the lesion using a scalpel blade. The collected scale is then placed on a glass microscope slide and treated with a solution containing 10-20% KOH. This treatment dissolves keratin, a protein found in the epidermis, making it easier to visualize fungal elements under a microscope.

KOH preparation is valuable for identifying various fungal infections, including dermatophyte infections (where hyphae are observed), Candida infections (showing pseudohyphae and budding yeasts), and tinea versicolor (characterized by "spaghetti and meatballs" yeast forms).

Tzanck Smear
Detecting herpesvirus infections

A Tzanck smear is a cytologic technique used primarily in the diagnosis of herpesvirus infections, such as herpes simplex virus (HSV) or varicella-zoster virus (VZV). The procedure involves unroofing an early vesicle (blister), not a pustule or crusted lesion, and gently scraping the base of the lesion with a scalpel blade. The collected material is placed on a glass slide, air-dried, and stained with Giemsa or Wright's stain.

Multinucleated epithelial giant cells observed in the smear suggest the presence of HSV or VZV. To identify the specific virus strain, further testing, such as culture, immunofluorescence microscopy, or genetic testing, is necessary.

Diascopy
Distinguishing skin lesions

Diascopy is a technique used to assess whether a skin lesion blanches (becomes pale) with applied pressure. This method helps distinguish between different types of skin lesions. For example, urticaria (hives) typically blanches with pressure, while purpuric lesions caused by necrotizing vasculitis do not.

During diascopy, a microscope slide or magnifying lens is pressed against the lesion, and the amount of blanching that occurs is noted. Granulomas often have a distinctive appearance on diascopy, appearing opaque to transparent with a brown-pink "apple jelly" appearance.

Dermoscopy
Noninvasive skin examination

Dermoscopy is a noninvasive method for examining the skin's surface. It involves using a high-quality magnifying lens and a specialized light source called a dermatoscope. Dermoscopy allows healthcare providers to identify skin structures, colors, and patterns that are not visible to the naked eye. This technique is particularly useful for evaluating pigmented skin lesions.

Wood's Light
Use of ultraviolet light

A Wood's lamp emits 360-nm ultraviolet ("black") light, which aids in the evaluation of specific skin disorders. For example, erythrasma, a superficial infection caused by Corynebacterium minutissimum, appears coral pink under a Wood's lamp. Wounds colonized by Pseudomonas may appear pale blue, and certain dermatophytes, like Microsporum canis or M. audouinii, exhibit a yellow fluorescence.

Pigmented lesions on the epidermis, such as freckles, become more accentuated under a Wood's lamp. In contrast, dermal pigmentation, like postinflammatory hyperpigmentation, tends to fade under this light. Vitiligo, characterized by depigmentation due to melanocyte loss, appears completely white under a Wood's lamp. Additionally, a Wood's lamp can be used to detect tinea versicolor and identify ash leaf spots in patients with tuberous sclerosis.

Patch Tests
Identifying sensitivity to antigens

Patch testing is a diagnostic procedure aimed at documenting an individual's sensitivity to specific antigens or allergens. This procedure involves applying a battery of suspected allergens to the patient's back under occlusive dressings. These dressings are left in place, in contact with the skin, for 48 hours. After removal, the area is examined for evidence of delayed hypersensitivity reactions, such as erythema (redness), edema (swelling), or papulovesicles (small, raised, fluid-filled lesions).

Patch testing is a specialized procedure typically performed by physicians with expertise in this area. It is especially valuable in the evaluation of patients with chronic dermatitis, as it can help pinpoint specific allergens or triggers responsible for the skin condition.

Conclusion
Specialized diagnostic techniques

In conclusion, skin examination is a fundamental aspect of medical practice, providing valuable insights into a patient's health. While many skin conditions can be diagnosed based on clinical appearance, specialized diagnostic techniques play a crucial role in confirming or clarifying diagnoses. These techniques, such as skin biopsy, KOH preparation, Tzanck smear, diascopy, dermoscopy, Wood's light examination, and patch testing, are essential tools in the dermatologist's toolkit. They enable healthcare professionals to provide accurate diagnoses and develop effective treatment plans for patients with various skin disorders. The choice of diagnostic technique depends on the specific clinical presentation and suspected underlying causes of the skin condition.


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Internal Medicine/Eczema and Dermatitis

Eczema and Dermatitis
Eczema is a term that is often used interchangeably with dermatitis. It represents a complex reaction pattern in the skin characterized by variable clinical findings and a common histologic finding known as spongiosis. Spongiosis refers to intercellular edema of the epidermis, a hallmark of eczema. Eczema serves as the final common expression for a variety of skin disorders, including those discussed in the following sections.

Primary Lesions in Eczema: In eczema, primary lesions may include erythematous macules (flat red spots), papules (small raised bumps), and vesicles (fluid-filled sacs). These primary lesions can coalesce to form patches (larger flat areas) and plaques (raised, flat-topped areas). In severe cases of eczema, secondary lesions stemming from infection or excoriation may predominate. These secondary lesions are often marked by weeping and crusting. In chronic eczematous conditions, lichenification occurs, which involves cutaneous hypertrophy and accentuation of normal skin markings, ultimately altering the characteristic appearance of eczema.

Atopic Dermatitis (AD)
Atopic dermatitis (AD) is considered the cutaneous expression of the atopic state, which is characterized by a family history of conditions such as asthma, allergic rhinitis, or eczema. Several defining features help identify AD:

 * 1) Pruritus and Scratching: AD is notorious for causing intense itching (pruritus), leading to frequent scratching, which further exacerbates the condition.
 * 2) Exacerbations and Remissions: The clinical course of AD is marked by periods of exacerbations, where symptoms worsen, followed by remissions, where symptoms improve.
 * 3) Typical Lesions: AD presents with lesions typical of eczematous dermatitis, including erythematous (red) and edematous (swollen) skin.
 * 4) Atopic History: Many AD patients have a personal or family history of atopy, which includes asthma, allergic rhinitis, food allergies, or other forms of eczema.
 * 5) Duration: AD typically persists for more than 6 weeks, distinguishing it from acute conditions.
 * 6) Lichenification: Chronic AD often leads to lichenification, which is the thickening and accentuation of skin markings.
 * 7) Dry Skin: Dry skin is a common characteristic, and patients often experience worsening pruritus in response to dryness.

Clinical Presentation by Age: The clinical presentation of AD can vary depending on age. Approximately half of AD patients present within the first year of life, and around 80% present by the age of 5. Infants with AD often display weeping inflammatory patches and crusted plaques on the face, neck, and extensor surfaces. In contrast, older children and adolescents typically manifest dermatitis on flexural skin, particularly in the antecubital and popliteal fossae.

Persistence into Adulthood: AD may resolve spontaneously in some cases, but approximately 40% of individuals affected as children will continue to experience dermatitis in adulthood. Regardless of age, pruritus remains a prominent characteristic of AD and is exacerbated by dry skin. Many cutaneous findings in affected patients, such as lichenification, result from persistent rubbing and scratching.

Treatment of AD
Effective treatment for AD involves a multifaceted approach:

 * Avoidance of Cutaneous Irritants: Patients are often advised to bathe no more frequently than once a day, using warm or cool water, and to use only mild bath soap.
 * Adequate Moisturization: Following a bath, a topical anti-inflammatory agent in a cream or ointment base should be applied to areas of dermatitis, while all other skin areas should be moisturized.
 * Use of Topical Anti-Inflammatory Agents: Low- to mid-potency topical glucocorticoids are frequently employed in the treatment of AD. However, choosing the right glucocorticoid and its potency should take into consideration factors like the location of application to minimize the risk of skin atrophy, especially on the face and in intertriginous areas.
 * Alternative Anti-Inflammatory Agents: Non-glucocorticoid anti-inflammatory agents, including tacrolimus ointment, pimecrolimus cream, and crisaborole ointment, have gained approval for topical use in AD. These agents do not cause skin atrophy and do not suppress the hypothalamic-pituitary-adrenal axis.

This multifaceted approach aims to control inflammation, alleviate pruritus, and prevent further exacerbations of AD.

Lichen Simplex Chronicus and Contact Dermatitis
Lichen Simplex Chronicus (LSC)

Lichen simplex chronicus often represents the end stage of various pruritic and eczematous disorders, including AD. It manifests as circumscribed plaques or lichenified skin due to chronic scratching or rubbing. Commonly involved areas include the posterior nuchal region, dorsum of the feet, and ankles. Treatment focuses on breaking the cycle of chronic itching and scratching, often involving high-potency topical glucocorticoids.

Contact Dermatitis

Contact dermatitis results from skin exposure to exogenous agents that directly or indirectly injure the skin. Irritant contact dermatitis (ICD) occurs due to an inherent characteristic of a compound, such as a concentrated acid or base, and can develop rapidly without prior exposure to the irritant. Allergic contact dermatitis (ACD) results from an antigen-specific immune response and requires prior exposure to the offending agent, often taking hours to days to develop. Common allergens causing ACD include poison ivy, poison oak, and poison sumac, typically manifesting as erythema, vesiculation, and severe pruritus.

Treatment for Contact Dermatitis

The treatment approach for contact dermatitis depends on whether it is irritant or allergic in nature. Removing the offending agent leads to resolution in most cases. High-potency topical glucocorticoids can help alleviate symptoms while the dermatitis runs its course. In severe cases, systemic glucocorticoids may be considered.

Hand Eczema and Nummular Eczema
Hand Eczema

Hand eczema is a common, chronic skin disorder influenced by both exogenous and endogenous factors. It is often associated with other cutaneous disorders like AD. Chronic exposure to water, detergents, harsh chemicals, or allergens can initiate or exacerbate this condition. It may present with dryness, skin cracking, erythema, and edema, often starting beneath rings where irritants are trapped.

Evaluation of Hand Eczema: Assessing potential occupation-associated exposures is crucial when evaluating hand eczema. The patient's history should aim to identify possible irritants or allergen exposures.

Treatment for Hand Eczema: Therapy involves avoiding irritants, identifying possible contact allergens, treating coexisting infections, and using topical glucocorticoids. Protecting the hands with gloves is advisable, preferably vinyl gloves to avoid potential hypersensitivity reactions associated with latex gloves.

Nummular Eczema

Nummular eczema is characterized by circular or oval "coinlike" lesions. It begins as small, edematous papules that become crusted and scaly. While its exact cause remains unknown, dry skin is a contributing factor. Common locations include the trunk and the extensor surfaces of the extremities, particularly the pretibial areas or dorsum of the hands. It is more common in men and often occurs in middle age. Treatment approaches for nummular eczema are similar to those for AD.

Asteatotic Eczema and Stasis Dermatitis/ulceration
Asteatotic Eczema

Asteatotic eczema, also known as xerotic eczema or "winter itch," is a mildly inflammatory dermatitis that develops in areas of extremely dry skin, especially during dry winter months. Clinically, it may overlap with nummular eczema. It presents with fine cracks, scale, erythema, and pruritus, typically on the anterior surfaces of the lower extremities in elderly patients. Asteatotic eczema responds well to topical moisturizers and the avoidance of cutaneous irritants. Overbathing and the use of harsh soaps can exacerbate this condition.

Stasis Dermatitis and Stasis Ulceration

Stasis dermatitis develops on the lower extremities due to venous incompetence and chronic edema. It may be associated with a history of deep venous thrombosis or varicose veins. The initial signs include mild erythema and scaling with pruritus. Stasis dermatitis can become acutely inflamed, mimicking cellulitis, especially if it occurs bilaterally. Chronic stasis dermatitis often results in dermal fibrosis, clinically seen as brawny edema, and pigmentation changes due to chronic erythrocyte extravasation and hemosiderin deposition. Severe stasis dermatitis may lead to the development of stasis ulcers.

Treatment for Stasis Dermatitis and Stasis Ulceration

Patients with stasis dermatitis and stasis ulceration benefit from leg elevation and the use of compression stockings with a gradient of at least 30–40 mmHg. Emollients and mid-potency topical glucocorticoids can be used to manage symptoms. Protection of the legs from injury, including scratching, is crucial to prevent ulcers. Diuretics may be necessary to control chronic edema. Stasis ulcers require elevation, gentle debridement, semipermeable dressing, and compression. Superficial bacterial cultures of chronic stasis ulcers may yield polymicrobial colonizers.

Seborrheic Dermatitis
Seborrheic dermatitis is a common, chronic condition characterized by greasy scales overlying erythematous patches or plaques. It is frequently observed as severe dandruff on the scalp and can affect various facial areas, external auditory canals, and postauricular regions. It may also develop in the central chest, axilla, groin, submammary folds, and gluteal cleft. Severe cases can lead to generalized dermatitis. Pruritus varies in intensity.

Seborrheic dermatitis can appear in infancy (often as cradle cap) and reappear during adolescence and adulthood. While it is associated with conditions like Parkinson's disease, cerebrovascular accidents, and HIV infection, most individuals with seborrheic dermatitis have no underlying disorder.

Treatment of Seborrheic Dermatitis: Treatment often involves low-potency topical glucocorticoids, topical antifungal agents (like ketoconazole or ciclopirox), and antidandruff shampoos for scalp involvement. High-potency topical glucocorticoid solutions are effective for severe scalp cases but should not be used on the face to avoid complications like steroid-induced rosacea or atrophy.

title: Internal Medicine/Eczema and Dermatitis


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Internal Medicine/Papulosquamous Disorders

Psoriasis
Psoriasis stands out as one of the most prevalent skin conditions globally, affecting up to 2% of the world's population. It is an immune-related disorder that exhibits distinct clinical features, including reddish, well-defined papules and circular plaques covered by a silvery, scaly layer. Psoriasis skin lesions can be itchy to varying degrees. Injured skin areas can also develop psoriasis lesions, known as the Koebner phenomenon. Additionally, external factors such as infections, stress, and certain medications like lithium, beta blockers, and antimalarial drugs can worsen psoriasis. The most common form is plaque-type psoriasis, characterized by stable, slow-growing plaques that remain relatively unchanged for long periods. Typically, these plaques appear on the elbows, knees, buttock creases, and the scalp, and they tend to appear symmetrically. Plaque psoriasis usually develops gradually and follows a mild course, seldom remitting spontaneously. Inverse psoriasis, on the other hand, affects skinfold regions like the armpits, groin, under the breasts, and navel, and it can also involve the scalp, palms, and soles. These lesions are well-defined plaques but may lack scaling due to their location.

Guttate psoriasis, or eruptive psoriasis, primarily affects children and young adults. It suddenly emerges in individuals without a prior history of psoriasis or in those with chronic plaque psoriasis. Patients with this type exhibit numerous small, reddish, scaly papules, often following upper respiratory tract infections caused by beta-hemolytic streptococci. The differential diagnosis should consider conditions like pityriasis rosea and secondary syphilis.

In pustular psoriasis, patients can have the disease localized to the palms and soles or a more generalized form. In both cases, the skin appears red, with pustules and varying degrees of scaling. When it's localized to the palms and soles, it can be easily confused with dyshidrotic eczema. In its generalized form, patients experience episodes characterized by fever, the eruption of sterile pustules, and intense redness. These episodes may even lead to erythroderma. Fever and pustular outbreaks tend to recur. Factors like local irritants, pregnancy, medications, infections, and discontinuation of systemic glucocorticoids can trigger this form of psoriasis. In nonpregnant patients, oral retinoids are the preferred treatment.

Fingernail involvement, which can manifest as small pits, separation of the nail from the nail bed, thickening, or excessive nail tissue underneath, can provide a clue to the diagnosis of psoriasis, particularly when the clinical presentation is atypical.

According to the National Psoriasis Foundation, approximately 30% of psoriasis patients develop psoriatic arthritis (PsA), which is most common between ages 30 and 50. PsA presents in various subtypes, including symmetric PsA, asymmetric PsA, distal PsA, spondylitis, and arthritis mutilans. Symmetric PsA often resembles rheumatoid arthritis and accounts for roughly 50% of PsA cases. Asymmetric arthritis, comprising about 35% of cases, can affect any joint and may cause "sausage fingers." Distal PsA, occurring in about 5% of PsA patients, involves fingers and toes and is often accompanied by nail issues like pitting. Spondylitis is observed in approximately 5% of PsA cases, while arthritis mutilans, the most severe form, primarily affects the small joints of the hands and feet and accounts for fewer than 5% of cases.

Psoriasis patients face an increased risk of metabolic syndrome, which includes a higher likelihood of cardiovascular events with increased morbidity and mortality. Therefore, appropriate screening tests are recommended. While the exact cause of psoriasis remains unclear, there is a definite genetic component, with 30–50% of patients reporting a family history of the condition. Psoriatic lesions contain infiltrates of activated T cells that produce cytokines responsible for the excessive growth of skin cells, leading to the characteristic clinical features. Treatments for severe psoriasis often involve agents that inhibit T-cell activation, clonal expansion, or proinflammatory cytokine release.

The treatment approach for psoriasis depends on the type, location, and extent of the disease. All patients should be advised to avoid excessive skin dryness or irritation and maintain adequate skin hydration. In most cases of localized plaque-type psoriasis, mid-potency topical glucocorticoids are effective, though their long-term use may lead to reduced effectiveness and skin thinning. Topical vitamin D analogs like calcipotriene and retinoids such as tazarotene are also suitable treatments for limited psoriasis and have largely replaced older topical agents like coal tar, salicylic acid, and anthralin.

Ultraviolet (UV) light, whether from natural or artificial sources, proves effective for many patients with widespread psoriasis. UVB, narrowband UVB, and UVA light with oral or topical psoralens (PUVA) are used therapeutically. UV light's immune-suppressing properties contribute to its therapeutic effect, but it is also mutagenic, potentially increasing the risk of nonmelanoma and melanoma skin cancers. Thus, UV-light therapy is contraindicated for patients taking cyclosporine and should be used cautiously in immunocompromised patients due to the elevated skin cancer risk.

For severe and extensive psoriasis, various systemic agents are available. Oral glucocorticoids are discouraged due to the risk of life-threatening pustular psoriasis upon discontinuation of treatment. Methotrexate is an effective option, especially for patients with PsA. The synthetic retinoid acitretin is useful when immunosuppression must be avoided but is limited by its teratogenic effects. Apremilast, a phosphodiesterase type 4 inhibitor, is approved for both psoriasis and PsA but should be used cautiously in the presence of renal failure or depression.

The understanding of psoriasis as a T-cell–mediated disorder has driven therapeutic research toward immunoregulation. Immunosuppressive agents like cyclosporine have shown efficacy in psoriasis treatment, and biologic agents with more selective immunosuppressive properties and improved safety profiles are being developed (see Table 57-4). These biologics have demonstrated effectiveness and good tolerability in treating psoriasis, though caution is necessary for certain patient comorbidities. Tumor necrosis factor-α (TNF-α) inhibitors, for example, may exacerbate congestive heart failure (CHF) and should be used carefully in patients with CHF or at risk for it. Moreover, none of the immunosuppressive agents used for psoriasis treatment should be initiated if the patient has a severe infection (including tuberculosis, HIV, hepatitis B or C), and patients on such therapy should be regularly screened for tuberculosis. There have been reports of progressive multifocal leukoencephalopathy and lupus erythematosus linked to TNF-α inhibitors. These systemic agents also carry an increased risk of skin cancer, necessitating close monitoring for its development.

Lichen Planus
Lichen planus (LP) is a papulosquamous disorder that can affect the skin, scalp, nails, and mucous membranes. The primary cutaneous lesions are itchy, polygonal, flat-topped, violet-colored papules. Examination of these papules often reveals a network of gray lines called Wickham's striae. LP can occur anywhere on the skin but has a preference for areas like the wrists, shins, lower back, and genitalia. It can also affect the scalp, leading to scarring hair loss, and the nails, potentially causing permanent deformities or nail loss. LP is often associated with mucous membrane involvement, particularly in the buccal mucosa, where it can range from a mild, white, reticulated rash to severe, erosive stomatitis. Erosive stomatitis may persist for extended periods and may elevate the risk of oral squamous cell carcinoma. Drug-induced LP-like eruptions have been observed with medications such as thiazide diuretics, gold, antimalarials, penicillamine, phenothiazines, and in patients with chronic graft-versus-host disease. LP may also be linked to hepatitis C infection. The course of LP varies, but most patients experience spontaneous remission within 6 months to 2 years after the disease onset. Topical glucocorticoids are the primary treatment.

Pityriasis Rosea
Pityriasis rosea (PR) is a papulosquamous rash of unknown origin that often occurs in the spring and fall. It typically starts with the development of a 2- to 6-cm circular lesion called the "herald patch." Over the following days to weeks, numerous smaller circular or papular lesions emerge, mostly on the trunk. These lesions are usually oval, with their long axis aligned with the lines of skin folds. Individual lesions can range in color from red to brown and often have a trailing scale. PR shares several clinical features with secondary syphilis, but palm and sole lesions are extremely rare in PR and common in secondary syphilis. The rash in PR is usually moderately itchy and persists for 3–8 weeks. Treatment aims at relieving itching and typically involves oral antihistamines, mid-potency topical glucocorticoids, and, in some cases, UVB phototherapy.


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Internal Medicine/Cutaneous Infections

Impetigo, Ecthyma, and Furunculosis
Impetigo is a common superficial bacterial skin infection primarily caused by Staphylococcus aureus and occasionally by group A β-hemolytic streptococci. The characteristic feature is the development of superficial pustules that rupture and form a characteristic honey-colored crust. These lesions can occur on healthy skin (primary infection) or in areas already affected by other skin conditions (secondary infection). Staphylococcal impetigo can sometimes manifest as bullous impetigo, where clear blisters form due to the production of exfoliative toxin. This toxin is also responsible for staphylococcal scalded-skin syndrome, which causes superficial epidermis loss due to blistering. Ecthyma is a deeper form of impetigo, often caused by Streptococcus pyogenes, leading to punched-out ulcerative lesions that heal with scarring. Treatment includes gentle debridement, topical antibiotics, and oral antibiotics as necessary.

Furunculosis is another condition caused by Staphylococcus aureus and has gained attention due to the emergence of community-associated MRSA (CA-MRSA). It presents as painful, erythematous nodules on the skin, commonly appearing in multiple lesions. Incision and drainage may be required for larger furuncles. It's important to culture lesional material whenever possible. Treatment for methicillin-sensitive infections involves β-lactam antibiotics, while CA-MRSA requires different approaches.

Dermatophytosis
Dermatophytes are fungi that infect the skin, hair, and nails and include Trichophyton, Microsporum, and Epidermophyton genera. Tinea corporis affects the hairless skin of the body and appears as erythematous, scaly plaques, often forming ring-like patterns. Tinea cruris, commonly found in males, presents as a scaling, erythematous rash sparing the scrotum. Tinea pedis, the most prevalent dermatophyte infection, causes variable symptoms on the feet, including erythema, edema, scaling, pruritus, and vesiculation. Tinea unguium or onychomycosis occurs in many patients with tinea pedis and results in thickened, opaque nails. Scalp infection (tinea capitis) predominantly affects children, causing mild scale and hair loss. Diagnosis is based on clinical appearance and microscopic examination.

Treatment options depend on the infection site and type. Topical agents work well for uncomplicated tinea corporis, tinea cruris, and limited tinea pedis. Griseofulvin is approved for dermatophyte infections, but it has side effects like gastrointestinal distress and headache. Itraconazole and terbinafine are sometimes used off-label for certain infections but require caution due to potential drug interactions and side effects.

Tinea (Pityriasis) Versicolor
Tinea versicolor, caused by Malassezia furfur, results in oval, scaly macules and patches, often found on the chest, shoulders, and back. Lesions can appear as hypopigmented areas on dark skin or slightly erythematous on light skin. A potassium hydroxide (KOH) preparation of lesions shows characteristic short hyphae and round spores, resembling "spaghetti and meatballs." Topical treatments like sulfur, salicylic acid, or selenium sulfide lotions or shampoos are the primary options and should be applied daily for a few weeks.

Candidiasis
Candidiasis is a fungal infection typically caused by Candida albicans. It can affect the skin and mucous membranes and is common in individuals with predisposing factors like antibiotic therapy, diabetes, or immunosuppression. Oral candidiasis (thrush) appears as white plaques on the tongue or buccal mucosa. Perlèche presents as fissured, macerated lesions at the corners of the mouth. Cutaneous candidal infections are often seen in moist, macerated areas and involve erythematous, edematous, and scaly skin with scattered "satellite pustules." Diagnosis is based on clinical presentation and microscopic examination.

Treatment involves removing predisposing factors and using appropriate topical or systemic antifungal agents. Topical options include nystatin or azoles, and mild glucocorticoid creams can be used for associated inflammation. Systemic therapy is reserved for immunosuppressed or chronic cases, with oral fluconazole being an option for cutaneous candidiasis.

Warts
Warts are skin neoplasms caused by human papillomaviruses (HPVs). They come in various forms, including verruca vulgaris, plantar warts, flat warts (verruca plana), and filiform warts. Genital warts are also caused by HPVs and can affect various genital and mucosal areas. Some HPVs are associated with an increased risk of cancer, such as cervical carcinoma.

Treatment of warts depends on factors like location, extent, patient age, and immune status. Cryotherapy with liquid nitrogen is effective for various warts. Keratolytic agents like salicylic acid can be used for nongenital warts. Podophyllin is an option for genital warts but can cause local reactions. Topical imiquimod is approved for genital warts. A vaccine for specific HPV types is available and reduces the risk of certain cancers associated with the virus.

title: Internal Medicine/Cutaneous Infections


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Internal Medicine/Acne

Acne Vulgaris
Acne vulgaris is a common, self-limiting skin condition primarily affecting teenagers and young adults, with a small percentage of adults continuing to experience it. The key trigger for acne during adolescence is the increased production of sebum (skin oil) by sebaceous glands due to puberty. This excess oil, combined with the retention of keratin and sebum in hair follicles, leads to the formation of small cysts called comedones. Bacteria, particularly Cutibacterium acnes, present in these comedones, release free fatty acids, causing inflammation within the cysts and leading to their rupture. As a result, an inflammatory response occurs due to the extrusion of oily and keratinous material from the cysts.

The primary feature of acne vulgaris is the comedone, which can be either closed (whiteheads) or open (blackheads). Closed comedones appear as small, raised white papules, while open comedones have a dilated follicular opening and contain darkened, easily expressible, oxidized debris. Comedones are often accompanied by inflammatory lesions such as papules, pustules, or nodules. Acne initially appears as mildly inflamed or noninflammatory comedones on the forehead in adolescence. Later, more typical inflammatory lesions develop on the cheeks, nose, and chin. The face is the most common site for acne, but it can also affect the chest and back. Most cases are mild and do not lead to scarring, but severe forms can result in significant and sometimes permanent scarring. Acne can have a significant impact on a person's quality of life, and early treatment is essential for severe cases.

Various external and internal factors can influence the development of acne, including friction or trauma, use of comedogenic cosmetics or hair products, topical exposure to certain industrial compounds, and certain medications. Genetic factors and conditions like polycystic ovary disease may also contribute to acne.

The treatment of acne vulgaris aims to eliminate comedones by normalizing follicular keratinization, reducing sebaceous gland activity, controlling Cutibacterium acnes population, and managing inflammation. Minimal to moderately inflamed acne can often be managed with topical therapy. It's important to keep the affected areas clean, but excessive scrubbing can worsen acne. Topical agents like retinoic acid, benzoyl peroxide, or salicylic acid can help prevent comedone formation and resolve existing cysts. Topical antibacterial agents (e.g., benzoyl peroxide, azelaic acid, erythromycin, clindamycin, or dapsone) can be used in combination with other treatments to prevent bacterial resistance.

Patients with moderate to severe acne and significant inflammation may benefit from oral antibiotics such as minocycline or doxycycline. These antibiotics have anti-inflammatory effects apart from their antibacterial properties. Female patients who don't respond to antibiotics might find hormonal therapy, including oral contraceptives, effective. Spironolactone is also emerging as a safe and durable antiandrogen treatment for women with acne.

In cases of severe, nodulocystic acne unresponsive to other treatments, isotretinoin, a synthetic retinoid, can be considered. It's administered based on body weight and cumulative dosage, with treatment duration determined by lesion remission. Isotretinoin has excellent results but is associated with potential severe side effects, including teratogenicity and depression. Its use is highly regulated to minimize these risks, including mandatory enrollment in a program to prevent pregnancy and monitor potential side effects.

Acne Rosacea
Acne rosacea, commonly known as rosacea, is an inflammatory skin condition primarily affecting the central face. It's most commonly observed in Caucasians of northern European descent but can also affect individuals with darker skin tones. Unlike acne vulgaris, rosacea typically occurs in adults and rarely affects those under 30. It's more prevalent in women, but men often experience more severe forms. Rosacea is characterized by facial redness, visible blood vessels (telangiectasias), and superficial pustules. Unlike acne vulgaris, rosacea does not involve comedones. The condition can lead to connective tissue overgrowth, particularly on the nose (rhinophyma), and can also affect the eyes, potentially causing various inflammatory eye disorders.

Rosacea can be treated through topical or systemic approaches. Mild cases often respond well to topical treatments like metronidazole, sodium sulfacetamide, azelaic acid, ivermectin, brimonidine, or oxymetazoline. More severe cases may require oral tetracyclines in subantimicrobial doses or modified-release preparations. Laser therapy can be effective for treating residual telangiectasia. It's important to avoid using potent topical steroids as chronic use can exacerbate rosacea. Topical treatments are ineffective for ocular involvement, and such cases require specialized treatment from an eye specialist.

title: Internal Medicine/Acne


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User talk:70.174.28.147

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Not a place to PR someone's video. LR0725 (discuss • contribs) 03:07, 5 September 2023 (UTC)

title: User talk:70.174.28.147


text:
Chess Opening Theory/1. e4/1...Nf6/2. e5/2...Nd5/3. d4/3...d6/4. c4/4...Nb6/5. f4/5...dxe5/6. fxe5/6...Nc6/7. Be3

=Alekhine Defence= With this move, White defends the d4-pawn with the bishop while not allowing the ...Bg4 pin. Black now almost always plays 7...Bf5, since that is the only logical square for the bishop. Then White plays 8.Nc3 and then Black plays 8...e6, and now White plays 9.Nf3 when Black has a choice between several moves.


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RadOnc Resident Wiki/Autonomic Nervous System

Tumors of the autonomic nervous system are relatively rare but can occur. The autonomic nervous system (ANS) controls involuntary bodily functions such as heart rate, digestion, respiratory rate, and pupillary response. It consists of two main branches: the sympathetic nervous system and the parasympathetic nervous system. Tumors that arise within or affect these components of the ANS can have various clinical manifestations and may be benign or malignant.

Here are some key points about tumors of the autonomic nervous system:

 * Types of Tumors: The most common type of tumor that affects the autonomic nervous system is a neuroblastoma. Neuroblastomas are often seen in children and typically arise from immature nerve cells. They can develop anywhere along the sympathetic nervous system, but they are most commonly found in the adrenal glands, which are located on top of each kidney.
 * Sympathetic Ganglioneuroma: This is a benign tumor that develops from nerve cells within sympathetic ganglia. It can occur in various locations along the sympathetic chain, including the chest, abdomen, and pelvis.
 * Paraganglioma: These tumors are typically benign, but they can be locally invasive. They originate from extra-adrenal paraganglia, which are clusters of specialized cells related to the sympathetic nervous system. Paragangliomas can develop in various areas of the body, including the head and neck, chest, and abdomen.
 * Pheochromocytoma: This is a rare type of tumor that arises in the adrenal glands. It is usually benign but can produce excessive amounts of catecholamines, which are hormones that regulate blood pressure and heart rate. As a result, pheochromocytomas can lead to severe hypertension and other symptoms.

 * Symptoms: The symptoms of autonomic nervous system tumors can vary depending on their location and whether they are benign or malignant. Common symptoms may include high blood pressure, rapid heart rate, abdominal pain, weight loss, and other signs of sympathetic nervous system dysfunction.

 * Diagnosis: Diagnosis typically involves a combination of imaging studies such as CT scans, MRIs, and specialized nuclear medicine tests. Biopsy or fine-needle aspiration may be required to confirm the type of tumor.

 * Treatment: Treatment options depend on the type, location, and stage of the tumor. Benign tumors may be surgically removed, and individuals often recover well. Malignant tumors may require a combination of surgery, chemotherapy, radiation therapy, and other targeted treatments. Pheochromocytomas, for example, often require medication to control blood pressure before surgery.

 * Prognosis: The prognosis for individuals with autonomic nervous system tumors varies widely. Benign tumors are usually associated with a good prognosis, while malignant tumors can be more challenging to treat and have a less favorable outlook.

It's important to note that while these tumors are rare, early detection and appropriate medical intervention are crucial for the best possible outcome. Medical professionals with expertise in neurology, oncology, and surgery are typically involved in the diagnosis and management of autonomic nervous system tumors.


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RadOnc Resident Wiki/Peripheral Nervous System

Tumors of the peripheral nervous system (PNS) are relatively uncommon but can affect various components of the peripheral nervous system, including nerves, nerve sheaths, and nerve cells. The PNS includes all the nerves outside of the brain and spinal cord. Tumors that originate in or affect the PNS can be benign (non-cancerous) or malignant (cancerous). Here are some key points about peripheral nervous system tumors:

 * Types of Tumors: There are several types of tumors that can affect the peripheral nervous system:
 * Peripheral Nerve Sheath Tumors: These tumors develop from the cells that form the protective covering (sheath) around peripheral nerves. The most common types include schwannomas and neurofibromas.
 * Schwannoma: Schwannomas arise from Schwann cells, which produce the myelin sheath around nerves. These tumors are often benign but can cause symptoms if they compress nearby nerves. Schwannomas can occur anywhere in the body but are frequently found in the head, neck, and extremities.
 * Neurofibroma: Neurofibromas develop from nerve tissue and can be associated with conditions like neurofibromatosis (genetic disorders that cause the growth of tumors along nerves). They can also be benign or, in rare cases, malignant.
 * Malignant Peripheral Nerve Sheath Tumors (MPNSTs): These are rare and aggressive cancerous tumors that arise from cells in the peripheral nerve sheaths. They can develop de novo or from pre-existing neurofibromas in individuals with neurofibromatosis.

 * Symptoms: The symptoms of peripheral nerve sheath tumors can vary depending on the location and size of the tumor. Common symptoms may include pain, weakness, numbness, tingling, and changes in sensation in the affected area. In some cases, these tumors can be asymptomatic and found incidentally during imaging studies.

 * Diagnosis: Diagnosis typically involves a combination of imaging studies such as MRI or CT scans to visualize the tumor's location and characteristics. Biopsy may be necessary to confirm the type of tumor and determine whether it is benign or malignant.

 * Treatment: Treatment options for peripheral nerve sheath tumors depend on factors like tumor size, location, and whether they are benign or malignant:
 * Benign Tumors: Small, asymptomatic benign tumors may be monitored without immediate intervention. If necessary, surgical removal is the primary treatment. Schwannomas, in particular, are often amenable to surgical excision with a good prognosis.
 * Malignant Tumors (MPNSTs): Treatment for malignant peripheral nerve sheath tumors typically involves a combination of surgery, radiation therapy, and chemotherapy. The prognosis for MPNSTs can be less favorable due to their aggressive nature.

 * Prognosis: The prognosis for individuals with peripheral nerve sheath tumors varies depending on several factors, including the tumor type, stage, and treatment. Benign tumors generally have a good prognosis if successfully removed. Malignant tumors, such as MPNSTs, can be more challenging to treat and may have a poorer outlook.

 * Specialized Care: Diagnosis and management of peripheral nerve sheath tumors often require a multidisciplinary approach involving neurosurgeons, orthopedic surgeons, oncologists, and other specialists with expertise in nerve-related conditions.

Early detection and appropriate medical intervention are essential for optimizing the outcome of individuals with peripheral nervous system tumors.


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RadOnc Resident Wiki/Abdomen

Tumors of the abdomen can involve various structures within the abdominal cavity and can be benign or malignant. The abdomen contains many organs, tissues, and structures, including the gastrointestinal tract, liver, pancreas, kidneys, adrenal glands, blood vessels, and connective tissues. Tumors that occur in the abdomen can arise from any of these structures. Here are some common types of abdominal tumors:

 * Gastrointestinal Tumors:
 * Colorectal Cancer: Cancer of the colon or rectum is one of the most common abdominal malignancies. Early detection through screening can significantly improve outcomes.
 * Stomach Cancer (Gastric Cancer): Tumors can develop in the lining of the stomach. Risk factors include Helicobacter pylori infection and dietary factors.
 * Liver Tumors: Hepatocellular carcinoma (HCC) is the most common primary liver cancer, often associated with chronic liver disease, while liver metastases can also occur from cancers in other parts of the body.

 * Pancreatic Tumors:
 * Pancreatic Cancer: Pancreatic adenocarcinoma is a highly aggressive cancer that originates in the pancreas. It is often diagnosed at an advanced stage, making it challenging to treat.

 * Kidney Tumors:
 * Renal Cell Carcinoma (RCC): The most common type of kidney cancer is RCC, which typically originates in the cells of the renal tubules. Early diagnosis and surgical intervention are essential for treatment.

 * Adrenal Tumors:
 * Adenomas and Adrenocortical Carcinomas**: Tumors can develop in the adrenal glands, which are located on top of the kidneys. These can be benign adenomas or rare malignant adrenocortical carcinomas.

 * Soft Tissue and Connective Tissue Tumors:
 * Gastrointestinal Stromal Tumors (GISTs): These are tumors that can develop in the gastrointestinal tract, often in the stomach or small intestine.
 * Desmoid Tumors: These are benign but locally aggressive tumors that can arise in the abdominal wall or mesentery.

 * Blood Vessel Tumors:
 * Hemangiomas and Angiomyolipomas**: These are benign tumors that can affect blood vessels and are occasionally found in the abdominal cavity.

 * Neuroendocrine Tumors:
 * Neuroendocrine Tumors (NETs): These can occur in various parts of the digestive system, including the pancreas, stomach, and intestines. They may be benign or malignant and produce hormones.

 * Lymphomas and Sarcomas: While less common, lymphomas and sarcomas can also occur in the abdomen.

Symptoms and treatment options for abdominal tumors can vary widely depending on the type, location, size, and whether they are benign or malignant. Common symptoms of abdominal tumors may include abdominal pain, bloating, changes in bowel habits, weight loss, and abdominal masses. Diagnosis typically involves imaging studies such as CT scans, MRIs, and biopsies to determine the nature of the tumor.

Treatment options may include surgery, chemotherapy, radiation therapy, targeted therapies, immunotherapy, and sometimes a combination of these approaches. The prognosis for abdominal tumors depends on multiple factors, including the stage of cancer at diagnosis, the type of tumor, and the effectiveness of treatment. Early detection and timely intervention are crucial for improving outcomes in individuals with abdominal tumors. A multidisciplinary team of healthcare professionals, including surgeons, oncologists, radiologists, and pathologists, often collaborates in the diagnosis and treatment of these tumors.

title: RadOnc Resident Wiki/Abdomen


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RadOnc Resident Wiki/Pelvis

Tumors of the pelvis can arise from various tissues and structures within the pelvic region. These tumors can be benign (non-cancerous) or malignant (cancerous). Pelvic tumors may originate in the bones, muscles, connective tissues, blood vessels, nerves, or organs located in the pelvic area. Here are some common types of pelvic tumors:

 * Ovarian Tumors: Ovarian tumors can be benign (e.g., ovarian cysts) or malignant (ovarian cancer). Ovarian cancer is a significant concern, as it can be challenging to detect in its early stages.

 * Uterine Tumors: Tumors of the uterus can be benign (e.g., uterine fibroids) or malignant (uterine cancer). Uterine fibroids are non-cancerous growths that can cause pelvic pain and other symptoms.

 * Cervical Tumors: Cervical cancer is a malignant tumor that forms in the cervix, the lower part of the uterus. Regular Pap smears are essential for early detection.

 * Prostate Tumors: In men, the prostate gland is located in the pelvic area. Prostate cancer is a common malignancy that can originate in this gland.

 * Colorectal Tumors: Tumors can develop in the colon or rectum, both of which are part of the lower digestive tract and are situated in the pelvic region. Colorectal cancer is a common malignancy.

 * Bladder Tumors: Tumors can form in the bladder, which is located in the lower pelvis. Bladder cancer is often characterized by blood in the urine and changes in urinary habits.

 * Bone Tumors: Pelvic bone tumors can be benign or malignant. Primary bone cancers, such as osteosarcoma or chondrosarcoma, can affect the pelvic bones.

 * Soft Tissue Tumors: Soft tissue tumors, including sarcomas, can develop in the muscles, connective tissues, and fat within the pelvic region.

 * Neurogenic Tumors: Tumors of the nerves can occur in the pelvis, such as neurofibromas or schwannomas. These are often benign, but they can cause symptoms if they compress nearby structures.

 * Blood Vessel Tumors: Rarely, tumors can develop in blood vessels within the pelvis. Hemangiomas and angiosarcomas are examples.

The treatment and prognosis for pelvic tumors depend on several factors, including the type of tumor, its size, location, and whether it is benign or malignant. Treatment options may include surgery, radiation therapy, chemotherapy, immunotherapy, targeted therapy, or a combination of these approaches. Early detection through regular medical check-ups and screenings is crucial for improving the chances of successful treatment and outcomes. If you suspect you have a pelvic tumor or have concerning symptoms, it's essential to consult a healthcare professional for a thorough evaluation and diagnosis.

title: RadOnc Resident Wiki/Pelvis


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