K E Y W O R D S : baboon syndrome, case report, cutaneous adverse drug reaction, nefopam, pristinamycin, secnidazole, systemic allergic dermatitis In 1984, Andersen et al 1 introduced the term "baboon syndrome" to describe a systemic contact dermatitis characterized by exanthema with involvement of the buttocks and flexure regions after the systemic absorption of a contact allergen (nickel, mercury, or ampicillin) in a sensitized patient. The rash looked like the red buttocks of a baboon. In 1983, Nakayama et al 2 published a report of 15 patients with symmetrical erythema predominantly on major flexural sites, which occurred 1 or 2 days after the breaking of a mercury thermometer. The non-contact allergic variant of baboon syndrome is also referred to as symmetrical drug-related intertriginous and flexural exanthema (SDRIFE).Since 1984, $100 cases of baboon syndrome or SDRIFE have been reported. We report 3 cases of SDRIFE, 1 each caused by pristinamycin, secnidazole, and nefopam. 3
CASE REPORTSCase 1. A 60-year-old man presented with an erythematosquamous rash of the inguinal and axillary folds and gluteal area ( Figure 1). He had been treated with candesartan for many years. He had recently been diagnosed with a bronchial infection, and was prescribed pristinamycin. The cutaneous rash appeared 2 days later. The results of laboratory tests were within normal limits, except for a mild biological inflammatory syndrome probably attributable to the infection. Histopathological analyses of a skin biopsy showed an orthokeratotic epidermis without keratinocytic necrosis, discrete spongiosis, and a lymphocytic infiltrate of the dermis with some eosinophils ( Figure S1).The clinical and histopathological signs confirmed the diagnosis of SDRIFE caused by pristinamycin, which was discontinued. The skin lesions completely regressed within 7 days. Two months later, the patient was patch tested with pristinamycin 30% pet. and 30% aq. on the back and in an inguinal fold. The results were negative on day (D) 2 and D3. The patient refused an oral provocation test. Case 2. A 44-year-old woman was treated with secnidazole for vaginitis caused by Trichomonas vaginalis. After 2 days, she developed a pruritic eczema-like eruption in the axillary, inguinal and submammary folds, with no other signs (Figure S2). She denied taking any other medication, and had a history of maculopapular exanthema caused by metronidazole and acetylsalicylic acid. Secnidazole was stopped, and topical betamethasone treatment was initiated. The lesions resolved within 4 days. SDRIFE caused by secnidazole was diagnosed, and patch tests were performed with secnidazole 30% pet. and 30% aq. These gave negative results on D2 on the back and in 1 affected area (breast), but a positive reaction on D4 on the breast (+), although the result remained negative on the back. Metronidazole and secnidazole may potentially cross-react, because both are sulfonamides.Case 3. A 68-year-old woman was referred with an erythematous Vrash of the buttocks, perineum, and axillary f...
