Langerhans cell histiocytosis and dermatophytosis.

Langerhans cell histiocytosis (LCH) is regarded as a disorder of histiocytic cell proliferation of the Langerhans type, probably resulting from altered immunoregulation. Cutaneous involvement is frequent and often appears as a scaling papular eruption that resembles seborrheic dermatitis; when limited to the scalp, scaling and erythema may also be confused with tinea capitis. We describe four patients who had LCH and documented dermatophyte infection versus colonization of the scalp. Fungal cultures should be considered in patients who have LCH with scalp involvement who do not respond to standard treatment; similarly, it may be appropriate to obtain a skin biopsy specimen from patients with recalcitrant tinea capitis to rule out the presence of underlying LCH.