Derm Dx: Hyperpigmented Axillary Macules

A 9-year-old girl presents for treatment of poison ivy. Upon examination, hyperpigmented macules are observed in the axillae, and her mother reports first noting these several months ago. The macules are asymptomatic. Family history is negative for genodermatoses including neurofibromatosis. The child is of normal development and mentation, and no additional cutaneous abnormalities are observed.