Scabies mimicking mastocytosis in two infants.

Scabies is a common parasitic human infection in infants and children. However, diagnostic pitfalls are frequent in infants, in whom the clinical presentation is usually atypical and different from that in adults. In nodular scabies, lesions may be clinically or histologically misdiagnosed as Langerhans cell histiocytosis, insect bite reaction, non-Langerhans cell histiocytosis, lymphoma, or urticaria pigmentosa. We report two misleading cases of young infants (10- and 12-month-old infants) who presented with pruritic brown-red lesions on their trunks and showing a positive Darier's sign, suggestive of urticaria pigmentosa.