A 7-year-old, previously healthy white girl presented with an 8-day history of blistering that had begun on the left arm and subsequently spread to the remainder of her body. The lesions were painful and pruritic. In the week before evaluation, she had been started on a regimen of cephalexin; prednisolone, 15 mg/d with taper; and ibuprofen. The presumptive diagnosis at that time was bullous impetigo. The lesions continued to progress despite the administration of corticosteroids. The patient and her family denied any recent illnesses, including upper respiratory tract infection, or new medications within the past 6 weeks. Her medical history included asthma, for which she had been taking montelukast sodium, albuterol, and fluticasone propionate for 2 years. Her family denied known allergies to medications. Immunizations were up-to-date, and there was no history of vaccination within the past 6 weeks. Findings from physical examination revealed an afebrile child with stable vital signs. Numerous tense vesicles and bullae with serous fluid resting on an erythematous base were evident on the patient's neck, chest, back, abdomen, perineum, and extremities. In several areas the vesicles were arranged in an annular pattern at the periphery of a crusted erosion, assuming a “cluster of jewels” appearance (Figure 1and Figure 2). There was sparing of the ocular and oral mucosa.