Isotretinoin In Preventing Recurrences In Chronic Recurrent Dermatophytosis
Isotretinoin In Preventing Recurrences In Chronic Recurrent Dermatophytosis
This study is a prospective, double blinded, randomized, pilot study to assess the
 effectiveness of oral low dose isotretinoin in combination with oral terbinafine and
 itraconazole in preventing recurrences in chronic recurrent dermatophytosis. The recruited
 patients will be randomized into four treatment arms; oral terbinafine alone and oral
 itraconazole alone versus oral isotretinoin in combination with each of these two antifungal
 agents. Randomization will be done using computer generated random number table. The patients
 in first treatment arm will receive 250 mg of oral terbinafine for 4 weeks, the patients in
 second treatment arm will receive oral itraconazole 200 mg twice a day for the same duration,
 while the patients in the third arm will receive oral terbinafine 250 mg once a day for 4
 weeks with oral isotretinoin 20 mg once daily and patients in the fourth arm will receive
 oral itraconazole 200 mg twice a day for 4 weeks with oral isotretinoin 20 mg once daily. In
 the third and fourth arms, oral terbinafine and oral itraconazole respectively will be
 stopped after 4 weeks while oral isotretinoin will be continued for 6 months with monthly
 monitoring of liver function tests and fasting lipid profile.The patients will be followed at
 monthly intervals for recurrence and treated appropriately.

 The primary objective is to evaluate the effectiveness of low dose isotretinoin (20 mg/day)
 in preventing recurrences in chronic recurrent dermatophytosis by comparing the frequencies
 of recurrence in patients who are on low dose isotretinoin during the follow up versus those
 who are not comparing the disease free interval between the four randomized groups at monthly
 follow up for a total duration of 6 months.
Over the last couple of years, the major concern in dermatophytic infections has been the
 occurrence of recurrent infections. This, in spite of the patients being treated with gold
 standard drugs, namely, terbinafine, griseofulvin, and even azoles like itraconazole, in
 adequate doses. The world is experiencing a menace of recurrent and chronic dermatophyte
 infections in a magnitude that is unprecedented. Such cases are making up a large proportion
 of cases seen every day in the outpatient department. To make matters worse, there is as yet,
 no standard definition of the terms 'çhronic', 'recurrent', or 'resistant' tinea infections,
 although arbitrary definitions exist, like 'chronic dermatophytosis' being described in lay
 terms as "patients who have suffered from the disease for more than 6 months to 1 year
 duration, with or without recurrence, in spite of being treated", and recurrent
 dermatophytosis being defined as the reoccurrence of the dermatophyte infection within few
 weeks, after completion of treatment.

 Alteration of immune pattern in dermatophytosis The development of antibodies (IgM, IgG, IgA
 and IgE) to dermatophyte infection seems not to substantially contribute to the elimination
 of fungal infections because highest antibody levels can be found in patients with chronic
 fungal infections. Studies by Jones in human volunteers suggested that cell-mediated immunity
 is the major immunologic defence mechanism in dermatophyte infection.Healthy volunteers
 infected with T. Mentagrophytes developed cell-mediated immunity resulting in mycologic cure.
 This was associated with intense inflammation due to T-cell mediated DTH, judging from the
 trichophytin skin test. A protective immunologic memory was indicated by elimination of T.
 mentagrophytes on re-inoculation and a continued positive trichophytin test. Impaired
 cell-mediated immunity in atopic persons is also believed to be the underlying mechanism for
 an increased susceptibility to T rubrum infections. Patients with allergic bronchial asthma
 or allergic rhinitis often develop chronic or recurrent fungal infections associated with
 high immediate-type hypersensitivity (high IgE levels) and low or waning DTH to trichophytin.

 Green et al. showed that athymic rats that lack T-cell-mediated immunity could not clear T.
 mentagrophytes infection in contrast to their genetically matched euthymic control rats.

 Chronic dermatophytosis is associated with a depression in cell-mediated immunity to
 dermatophytes. A selective antigen-specific immunodeficiency may be the underlying factor in
 such patients, and the continued presence of infecting dermatophytes or residual fungal
 elements may induce a tolerant state by flooding the host with antigenic material, resulting
 in a selective loss of cell-mediated immunity. Alternatively, fungal elements may interact
 with host skin to alter the cytokine milieu such that effective type I immune responses for
 eliminating organisms are suppressed. In a study done to evaluate immune response in T rubrum
 onychomycosis and to determine whether immune reactivity or nonreactivity can be a predictor
 of therapeutic outcome, a double-blind comparison was done of the effects of terbinafine with
 placebo tablets. Skin tests were performed using trichophytin antigen injected intradermally
 in the upper left arm. It was found that skin reactivity to trichophytin antigen decreases
 with increasing disease chronicity. Patients with longstanding disease demonstrated absent or
 significantly blunted skin reaction to trichophytin antigen compared with patients who had
 disease for less than 5 years. Patients who were reactive at baseline were the first to
 become mycologically negative in response to terbinafine treatment, and increases in skin
 reactivity were related to conversion to negative mycology. Subjects anergic at baseline who
 converted with treatment had a more favorable outcome overall than persistent nonconverters.
 It is already known that terbinafine and azoles eliminate the fungal elements and restore
 cellular immunity resulting in eradication of the oragnisms and cure of the infection. In our
 study, we plan to analyse if low dose oral isotretinoin has any role to play in the
 maintenance of the cure achieved by itraconazole by decreasing the number of relapses and
 whether it leads to an alteration of skin reactivity to trichophytin. If indeed we observe
 that isotretinoin does, in fact, reduce the number of relapses, it would be interesting to
 know if there is an immunological basis for this, given that isotretinoin is known to be an
 immunomodulator.

 Probable antifungal Resistance Mechanisms in Dermatophytes In vivo, anti fungal resistance is
 also correlated with antifungal misuse because patients often fail to finish the full course
 of treatment. Thus, the inadequate use or dosage of drugs contributes to the failure in
 eliminating the disease agent completely, encouraging growth of the most resistant strains,
 which may lead to hard-to-treat fungal infections.

 Only few reports have addressed the drug resistance mechanism in dermatophytes, and most of
 them have been described in T. rubrum. It is noteworthy that resistance to a particular drug
 can be achieved by more than one mechanism and probably, under certain circumstances, they
 are activated simultaneously.

 Although dermatophytes have powerful metabolic machinery for survival, they have to overcome
 many pitfalls imposed by the host. Thus, dermatophytes have developed mechanisms that allow
 them to avoid the host defences such as the immunosuppressive action of fungal mannans that
 causes reduction of inflammation and phagocytosis. The chemical composition of the cell wall
 of dermatophytes plays an important role in pathogenicity because of the existing correlation
 between alteration in the chemical composition of the cell wall, cell dimorphism and
 virulence.

 Probable role of Isotretinoin against dermatophytes Following adherence, successful
 installation of dermatophytes requires rapid germination of arthroconidia and penetration of
 hyphae into the stratum corneum. Failure to do so results in elimination by the continuous
 desquamation of the epithelium. Retinoids act as modulators of epidermal growth and
 differentiation. Although they normalize proliferation in hyperproliferative epithelia as in
 psoriasis; in normal epidermis, they promote cell proliferation. Therefore, increased cell
 turnover in the epidermis may halt the spread of ongoing infection by eliminating the growing
 dermatophyte. Retinoids are also known to alter terminal differentiation towards a
 non-keratinizing, metaplastic and mucosa-like epithelium.

 Another aspect is the altered glycosylation pattern of normal skin treated with retinoic acid
 that resembles that of mucosal epithelium with a reduction of tonofilaments, decreased
 corneocyte cohesiveness, impaired function of the permeability barrier and increased
 transepidermal water loss. This could thus explain the keratolytic effect of retinoids in
 hyperkeratotic disorder and could be extrapolated to any probable role of isotretinoin that
 we see in chronic and recurrent dermatophyte infections.

 Once established, the dermatophytes must scavenge for nutrients for growth, a process
 dependent on the induction of structural proteins, permeases and enzymes of the cell wall, in
 addition to the secretion of a variety of proteins and hydrolytic enzymes such as nucleases,
 lipases, non-specific proteases and keratinases that occur in response to a shortage in the
 supply of essential nutrients in the host. Dermatophytes de-repress non-specific proteolytic
 enzymes and keratinases which have optimum activity at acidic pH and are important virulence
 factors. Thus, their growth is dependent on the pH of the skin which being acidic gives an
 ideal ambient environment for the fungus. High transepidermal water loss values and impaired
 barrier function of the skin are correlated with high skin pH. Retinoid therapy is known to
 raise the skin pH, thereby possibly inhibiting dermatophyte growth.

 Retinoids are generally thought to stimulate humoral and cellular immunity. They can enhance
 antibody production and stimulate peripheral blood T helper cells. Cell surface antigens of T
 cells and natural killer cells have been reported to increase after retinoid exposure in
 vitro. On the other hand, dermatophytes have mechanisms that allow them to evade the host
 response such as the immunosuppressive action of fungal mannans that causes reduction of
 inflammation and phagocytosis. Retinoids may counteract some of these immunosuppressive
 effects of the dermatophyte.

 Finally, although more often associated with bacteria, pure fungal biofilms are a recognized
 entity, especially in yeasts like candida. Unlike candidal infections where the concept of
 fungal biofims has received considerable attention and is established, the same is not true
 for dermatophyte infections. Though it was introduced by Burkhart et al. to explain
 dermatophytomas, a form of onychomycosis refractory to standard antifungal therapies, it is a
 relatively virgin territory with hardly any published literature. The anecdotal efficacy of
 minocycline and isotretinoin in noninflammatory comedonal acne is more easily explained by
 their effects on altering the P acnes biofilm and lowering production of biological glue
 present in the biofilm. If the investigators can extrapolate the role of isotretinoin in P
 acnes biofilm to that of dermatophytes, it could potentially lead to tremendous insights into
 using an old but extremely efficacious drug for a novel indication.

 Study design:

 This will be a randomized open label single centre study. It will involve recruitment of
 patients with recurrent cutaneous dermatophytosis based on inclusion and exclusion criteria.
 The participants will be randomized (by block randomization) into four arms - Arm A will be
 treated with tablet terbinafine 250 mg once a day for 4 weeks, arm B will receive tablet
 terbinafine 250 mg once a day with low dose isotretinoin 20 mg/day, arm C will receive
 capsule itraconazole 200 mg/ day for 4 weeks, and arm D will be treated with capsule
 itraconazole 200 mg/ day for 4 weeks along with low dose isotretinoin (20 mg/day). Allocation
 concealment will be done by the sequentially numbered, opaque, sealed envelopes (SNOSE)
 method. After 4 weeks of treatment, arms B and D will continue to receive isotretinoin during
 subsequent 5 months of follow up.

 Methodology All adults attending General OPD, Department of Dermatology, Venereology and
 Leprology, PGIMER, Chandigarh and satisfying the inclusion and exclusion criteria shall be
 eligible for recruitment in the present study after patients sign the written informed
 consent form. Complete physical examination including cutaneous, general and systemic
 examination will be done and recorded in case record proforma (annexure 1). Baseline clinical
 photographs will be taken for all patients.
Inclusion Criteria:

 • All patients with chronic recurrent dermatophytosis of more than 6 months duration who
 have been adequately treated for every episode still developing recurrences within one
 month of stopping oral antifungal drugs.

 Exclusion Criteria:

 -  Patients with contraindications to receiving oral terbinafine, itraconazole or
 isotretinoin like those suffering from congestive cardiac failure, cardiac
 arrhythmias, liver or kidney function impairment or are on drugs whose plasma
 concentrations are likely to be increased by the concurrent administration of oral
 itraconazole.

 -  Pregnancy and lactation.

 -  Patients on immunosuppressive drugs.

 -  Immunocompromised patients (HIV positive/renal transplant etc).