Cutaneous mastocytosis exacerbated by pinworms in a young boy.

Cutaneous mastocytosis in children has an indolent course and undergoes spontaneous regression. Many triggering factors may cause mast cell degranulation and clinical manifestations. Knowledge of these factors is important for patients and their families. We report a case of exacerbation of urticaria pigmentosa due to mast cell degranulation caused by Enterobius vermicularis, which has not been reported before as a triggering factor.