Postherpetic Nevocentric Erythema Multiforme.

A previously healthy 35-year-old Caucasian woman presented with abrupt onset of erythematous, mildly pruritic plaques surrounding the majority of the nevi present on her neck, chest, back, and upper and lower extremities. She denied history of any recent systemic illnesses and was not taking any medications. On further questioning, the patient reported a recent episode of recurrent herpes labialis 2 weeks prior. The patient has a Fitzpatrick type I skin type with more than 100 brown and reddish brown pigmented macules and papules over her entire body. Plaques ranged in size from 0.4 cm to 1.5 cm depending on the size of the corresponding nevus. The patient's skin was examined in its entirety, and there were no lesions suspicious for melanoma. Two biopsies were performed from the patient's back: one from the nevus itself and another from the surrounding erythematous plaque. The nevocentric erythematous plaques were visible for approximately 1 week at which time they gradually disappeared without treatment. As these areas improved, the patient noticed targetoid lesions on the dorsal hands without associated nevi. Two weeks later, the targetoid lesions had spontaneously resolved.