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Paper text:
psoriasis is a chronic t - cell - mediated inflammatory disease affecting the skin and joints .
recent epidemiological studies have shown that psoriasis patients are prone to develop cardiovascular and other metabolic syndromes .
on the other hand , a variety of cutaneous disorders may be associated with psoriasis .
occurrence of autoimmune blistering disease in psoriasis is rare ; here we report a case of coexistence of psoriasis with bullous pemphigoid ( bp ) .
a 57-year - old male presented with history of blisters all over the body of 10 days duration .
the blisters were noticed first on the arm and later spread to other parts of the body .
he had used both modern medicines and alternative medicines for psoriasis for a variable amount of time ; in particular , antipsoriatic treatment was discontinued 26 months before the presentation .
cutaneous examination revealed tense bullae and crusted erosions on upper and lower limbs [ figure 1 ] .
blisters were present both over the scaly plaques as well as on the normal skin [ figure 2 ] .
the skin biopsy from scaly plaque was consistent with the diagnosis of psoriasis and showed hyperkeratosis , parakeratosis , acanthosis , regular elongation of rete ridges .
direct immunofluorescence of the perilesional skin showed a strong linear basement membrane zone ( bmz ) band with c3 and a weak bmz band with igg [ figure 3 ] ; salt split study of skin biopsy ( direct salt split ) showed bmz band on the epidermal side (  roof pattern ) confirming the diagnosis of bp [ figure 4 ] .
indirect immunofluorescence using human skin as substrate showed linear bmz band in serial dilutions of 1:10 and 1:80 .
patient was treated with methotrexate 10 mg / week orally along with topical betamethasone in cream base ( 0.3% ) . at 1-month follow - up ,
psoriatic lesions have improved ; he used to get occasional new blisters . at 3-month follow - up , both conditions have subsided with postinflammatory pigmentation .
hyperpigmented scaly plaques on the thighs ; single bulla on the normal skin on the left thigh .
linear basement membrane zone band with igg seen on the epidermal side of the salt split skin ( dif , x20 ) .
since the initial description of coexistence of bullous disease and psoriasis by bloom in 1929 , several autoimmune bullous diseases associated with psoriasis have been reported in literature .
these include pemphigus vulgaris ( pv ) , pemphigus foliaceus ( pf ) , pemphigus herpetiformis , bullous pemphigoid ( bp ) , linear bullous dermatoses ( lad ) , cicatricial pemphigoid ( cp ) , epidermolysis bullosa acquisita ( psoriasis bullosa acquisita ) and a novel bullous dermatoses targeting 200 kda molecule present in the lower lamina lucida.[69 ] among these , bp is the most frequent condition to be associated with psoriasis ( psoriasis pemphigoides ) ; less than 50 cases of such association have been described in the english literature .
this association is reported to be more common among men than women with an average age of onset at 63 years . in most cases ,
psoriasis preceded the development of bp , with an average time interval of 20 years ( range , 160 years ) between the two conditions .
whether the treatment of psoriasis , pathological events at the basement membrane zone ( bmz ) in psoriasis itself , common immunological or immunogenetic mechanisms , or a coincidence of multiple factors precipitates the autoimmune bullous diseases in these patients remain controversial . since the coexistence was seen in patients who received wide range of treatment for psoriasis as well as in untreated patients , it is difficult to incriminate a single agent as a potentially causative factor in the development of bp . reduced barrier function of the diseased psoriatic epidermis , combined with the irritant effects of therapies administered for psoriasis , such as anthralin , tar , and ultraviolet light , together with a low - grade immunologic bmz insult , may precipitate blister formation . cram and fukuyama demonstrated the triggering role of ultraviolet light b ( uvb ) in the induction of bp .
psoralen and ultraviolet light a ( puva ) therapy is also known to induce blisters mimicking bp .
this molecule , however , has been withdrawn now from the market due to serious neurological side effects .
changes at the bmz in psoriasis itself may be responsible for precipitating the bullous disease .
the presence of chronic inflammation , trafficking of activated lymphocytes and abundance of antigen presenting cells in psoriasis could unmask , expose or alter bmz antigens , giving rise to autoantibody production .
electron microscopy studies have shown a focal discontinuity and reduplication of the basal lamina in psoriasis .
the concept of  epitope spreading  whereby tissue damage from a primary inflammatory process causes the release and exposure of a previously  sequestered antigen , leading to a secondary autoimmune response against the newly released antigen , may provide us with a unifying explanation for the development of subepidermal bullous disorders .
common immunogenetic or immunological mechanisms may also play a crucial role in this disease association .
psoriasis has been associated with other autoimmune diseases such as discoid and systemic lupus erythematosus , myasthenia gravis , crohns disease and ulcerative colitis . it may be suggested that psoriasis provides a particular predisposition of the immune system that , under certain circumstances leads to autoimmune response .
circulating antibodies against components of the malpighian layer and stratum corneum have been detected in the serum of psoriatic patients .
the dysregulation of t - cell activity in psoriasis might result in the induction of specific antibodies to basement membrane antigens .
however , recent studies have established that th17 is the primary pathogenetic subset ; this subset of t cell also plays a key role in autoimmunity .
other drugs that have shown to be beneficial include dapsone , azathioprine , cyclosporine , erythromycin with etretinate .
we have treated our patient with methotrexate ( 10 mg per week ) . at 3-month follow - up
we believe that this is the first case report of psoriasis vulgaris coexistent with bp in indian literature .
psoriasis vulgaris and bullous pemphigoid ( bp ) represent two clinically well - characterized , chronic , inflammatory skin conditions . 
 the concomitant occurrence of these two entities in a patient is rare . 
 here we report a 57-year - old male suffering from psoriasis vulgaris for 15 years on irregular medication who noticed eruption of blisters all over the body . 
 we believe that this is the first case report of psoriasis vulgaris coexistent with bullous pemphigoid in indian literature . 
 please check where you want bullous pemphigoid and where you want psoriasis pemphigoides .