Exophytic Nodule on the Scalp—Quiz Case

A 23-year-old, otherwise healthy woman presented to the emergency department with a 2-day history of subjective fevers and a 1-day history of rapid onset of pruritic, pink plaques on her arms, legs, lower back, neck, and face. She denied any other systemic symptoms, new medications, allergies, or a history of cutaneous eruptions. On physical examination, she had a fever of 101.2 F and had erythematous targetoid plaques with violaceous central bullae that were grouped on her extremities, back, face, and neck (Figure 1). There was no evidence of mucosal involvement. Results from laboratory tests, including complete blood cell count, comprehensive metabolic panel, and human immunodeficiency virus, were all normal. A biopsy was performed for histopathologic evaluation (Figure 2 and Figure 3). What is your diagnosis?