[Diaper dermatitis is not always a harmless condition].

BACKGROUND: Diaper dermatitis in children is common and usually harmless. Often the cause is irritation, a secondary candida infection or eczema, for which treatment is simple and effective. In this paper we show that a therapy resistant diaper dermatitis can be the diagnostic clue to the rare but important diagnosis Langerhans cell histiocytosis (LCH). CASE DESCRIPTION: We saw a 14 months old girl with therapy resistant diaper dermatitis, skin abnormalities on the hairy scalp, fever, otorrhea and extensive lymphadenopathy. After a long period of doctor visits, skin biopsies confirmed the diagnosis of LCH. CONCLUSION: LCH is a rare condition that often manifests in the skin. LCH can manifest in different organs. Although skin involvement is sometimes considered as less relevant, cutaneous manifestations can be an important diagnostic clue. In this paper we show that diaper dermatitis is not always harmless: it can be a symptom of LCH.