[A rare form of rifampicin-induced skin toxicity: bullous pemphigoid]

Introduction: Rifampicin is an antituberculous drug causing minor cutaneous reactions. Rifampicin-induced bullous skin reactions are rare.

Case report: We describe a 48-year-old man who was given rifampicin, streptomycin, isoniazid and pyrazinamide for pulmonary tuberculosis. Seventy-two hours later, he developed generalized pruritus, and an urticarial eruption developed 5 days later. He was admitted to hospital and the drugs were discontinued. He could remember no history of previous administration of antituberculous drugs and no other drugs had been taken recently. General physical examination yielded no relevant findings. On dermatological examination, Nikolsky's sign was negative. There were tiny symmetrical cutaneous vesicles overlying normal skin of all four limbs. These rapidly became confluent, forming large tense bullous lesions containing clear fluid, suggesting bullous pemphigoid. Blood tests showed a neutrophil leukocytosis and mild eosinophilia. Other biological tests were normal. Skin biopsy was refused by the patient. He was given intravenous antihistamine and dry bandages were applied to the forearms and legs. The antituberculous drugs were discontinued for two weeks and the lesions healed spontaneously. The drugs were then progressively reintroduced, streptomycin being excluded initially. A few hours after the first dose of rifampicin, a recurrence was noted and it was substituted by ethambutol. Subsequent introduction of streptomycin was uneventful. No recurrence occurred over 18 months follow up.

Conclusion: The authors describe a rare case of rifampicin-induced skin toxicity and the related diagnostic and therapeutic difficulties.