LAUSR

A 60-year-old otherwise healthy man presented with a 1-week history of a mildly stinging erythematous eruption involving the buttocks and the flexural areas, including the axillae and the groins. His past medical history was significant for a recently diagnosed tinea pedis for which he was prescribed terbinafine HCl 125 mg tablets twice a day for 2 weeks about 10 days prior. On the third day of initiating treatment with terbinafine, a flexural rash was noted affecting the axillae. Despite the rash, he continued taking the medication for another few days, but as the rash worsened and progressed to involve the groins and upper inner thighs, he consulted his GP who immediately stopped the patient’s medication and referred him to a dermatologist. Physical examination revealed an erythematous eruption symmetrically involving the axillae, sides of the trunk, midsternal groove, antecubital fossae, groins, and the perianal and gluteal areas. It appeared as large welldemarcated dusky red patches with central confluence (Fig. 1). Superficial peripheral desquamation was also noted particularly around the axillae (Fig. 1). There were no raised or advancing margins at the periphery, and the superficial scrapings from the multiple affected sites showed no fungal elements on microscopy of the potassium hydroxide-treated samples. He was otherwise well, and there was no recent history of any upper respiratory tract infection, pharyngitis, or fever. He had not taken any other medications recently except terbinafine. According to his previous medical record, he had not been prescribed topical and/or oral terbinafine before. There was no personal and/or family history of atopic diatheses or any other drug hypersensitivity. His routine blood and urinalyses were unremarkable. Antistreptolysin titer was also within normal limits. Patch tests, carried out with terbinafine HCl, prepared in petrolatum and water as a vehicle, at different concentrations (5, 10, and 30% according to the guidelines of the International Contact Dermatitis Research Group) remained negative after 48 and 72 hours. Histopathologic examination of the biopsy from the affected sites showed a mixed, predominantly mononuclear perivascular infiltrate in the dermis. After clinicopathologic correlation, a diagnosis of drugrelated baboon syndrome (BS) or symmetrical drugrelated intertriginous and flexural exanthema (SDRIFE) was made. A drug provocation test was refused by the patient. He was treated with saline compresses and mild topical steroids. The eruption appeared to have cleared with desquamation when the patient was seen at the follow-up examination after 1 week.