A 10-year-old otherwise healthy boy had a 4-day history of a dusky-red plaque on his right thigh, measuring 10×6 cm, with an erythematous periphery. Later, bullae developed on top of the plaque, and other lesions appeared on the trunk, limbs and penis (figure 1). Previously he had manifested an identical plaque in the same area (right thigh), with residual hyperpigmentation, that lasted 3 weeks. Due …