Nail involvement in histiocytosis X. A 12-year retrospective study.

A retrospective study of nail involvement was made in 15 cases of histiocytosis X (HX). These included seven cases of Letterer-Siwe (LS) disease, four cases of Hand-Schüller-Christian disease, and four cases of eosinophilic granuloma seen at Ramathibodi Hospital, Bangkok, Thailand, during the years 1970 to 1981. Nail involvement was found in three patients with LS disease, two of whom showed fingernail and toenail dystrophy with onycholysis and subungual hyperkeratosis. Paronychial erythema and swelling with small pustules underneath some nails were seen in both of the latter patients. The remaining patient showed subungual purpura of all fingernails and toenails with slight thickening of some fingernails. The nail changes in one patient responded well to cytotoxic therapy but recurred when the disease progressed. Nail involvement seems to be one of the unfavorable prognostic signs in HX.