AN 8-MONTH-OLD African American male infant was seen for evaluation of a rash that had been present on his right leg since age 3 months (Figure 1 and Figure 2). Since the eruption began, the infant's mother reported that it had spread somewhat but was otherwise completely asymptomatic. The infant was healthy with normal growth and development. No skin lesions were present elsewhere on the body, and findings from the remainder of the physical examination were unremarkable. He had not been given any medications. His family history was significant for atopic dermatitis in several maternal relatives. Results of a skin biopsy specimen are shown in Figure 3.