REPORT OF A CASE
A 9-month-old male infant was referred because of asymptomatic pigmented papules in the left axilla (Fig 1). The lesions were first noted at age three months with an increase in number during the next three months. Although the lesions were usually tan, they occasionally seemed red. The child was otherwise in good health and there was no family history of medical or dermatologic disease.Examination revealed several round and oval tan papules in the left axillary area. The remaining skin and mucosal surfaces were free of lesions. Diagnostic procedures consisted of stroking one papule with the edge of a tongue blade (Fig 2) and performing a 3-mm punch biopsy on one of the other papules for specific histologic stains (Figs 3 and 4).What is your diagnosis?
Urticaria pigmentosa (UP) (mastocytosis).
The clue to the correct diagnosis in
O'Connell BM, Nickoloff BJ, Jacobs AH. Pigmented Papules in the Axilla. Arch Dermatol. 1988;124(9):1425-1426. doi:10.1001/archderm.1988.01670090081021