Histiocytosis: Skin manifiestation

Cutaneous abnormalities are present in almost 80% of patients, frequently as the first sign. Skin lesions may be the only evidence of the disease or may be part of systemic involvement. The eruption may be extensive, involving the scalp, face, trunk, buttocks, and intertriginous areas. Lesions consist of closely set petechiae and yellow-brown papules topped with scale and crust. The papules may coalesce to form an erythematous, weeping or crusted eruption mimicking seborrheic dermatitis.