A woman with recurrent erythema and vesicles on her legs

A woman in her 20s presented with a two year history of recurrent (20 episodes) erythema and painful vesicles on her legs and recurrent (24 episodes) small clusters of pruritic blisters on her right lower buttock. The blisters coincided with fatigue and menstruation. On six occasions over the past year and a half she had experienced erosions on her tongue and buccal mucosa. Within the past month red papules, with unclear ring-shaped borders and mild scaling, had appeared on her left buttock. Occasionally, she had scattered erythema with blisters on her arms and trunk. Oral steroids were initially tried for suspected Behcet’s disease and Sweet syndrome. The lesions on the limbs, trunk, tongue, and buccal mucosa improved but recurred when the patient stopped treatment. Thalidomide and tetracycline were also tried for Behcet’s disease and Sweet syndrome, but response was poor. The patient had used ibuprofen for pain relief when the leg vesicles ruptured and became erosions. On examination, lesions were observed on the right lower buttock, and tender erythematous lesions had developed on the legs and thighs three days earlier. Grouped vesicles on an erythematous base …