Tinea incognito hidden under apparently treatment-resistant pemphigus foliaceus.

A 68-year-old woman who had had pemphigus foliaceus for 13 years, presented for initiation of more aggressive therapy due to gradual continuous clinical worsening in the last 3 months despite potent topical steroid and long-standing systemic therapy with prednisolone 50 mg/day for one year. At the time of presentation desmoglein-1 antibodies were detectable to a low grade using enzyme-linked immunosorbent assay (ELISA). Clinical examination revealed a bizarre pattern of non-pruritic, brownish circinate plaques, covered with white-greyish greasy scales, which affected excessive areas of the body, with accentuation in the facial, lower torso and buttock areas (Fig. 1). There were no signs of tinea pedis or nail involvement. Histological and immunohistochemical examination revealed no evidence of active pemphigus foliaceus. However, periodic acid-Schiff (PAS) stain, fungal culture and polymerase chain reaction (PCR) analysis showed abundant Trichophyton rubrum, leading to the diagnosis tinea incognito. The patient commenced oral treatment with itraconazole 100 mg/day for 4 weeks, in addition to local therapy with ciclopiroxolamine cream once a day with cessation of all topical steroids. In order to decrease the need for systemic corticosteroids and to maintain complete remission of the bullous autoimmune disease with minimum adverse effects, we began maintenance treatment with azathioprine by concurrently tapering the prednisolone daily dosage under 7.5 mg. A follow-up examination 6 months later showed complete resolution of the fungal infection with no recurrence of pemphigus foliaceus.