A 9-year-old boy presented with an 8-month history of a rash on his left thigh, leg, and foot. He described these areas as occasionally itchy but denied pain or other symptoms. At initial presentation,
he was treated with topical corticosteroid and adapalene creams, with no improvement. His only medication was biweekly allergy shots for a history of hives and anaphylaxis, and his family history was remarkable for seasonal allergies and asthma.
Physical examination revealed an ill-defined brown-yellow patch on the left hip that contained cayenne pepper–like red macules.
There were also multiple grouped, violaceous, polygonal purpuric plaques with slight scale on the left thigh (Figure 1), popliteal fossa, ankle, and dorsal aspect of the foot.
A punch biopsy specimen was obtained from the left calf (Figure 2 and Figure 3).