We believe Netherton originally described an unusual syndrome, although the atopic manifestations in his patient did not appear for some years after his report. The three cases so far reported had these features in common: trichorrhexis invaginata, congenital ichthyosiform erythroderma, some of the manifestations of atopy, and the fact that they were females. We assume at this time that the ectodermal features may be transmitted as a sex-linked autosomal recessive trait affecting only females and is in association with the atopic diathesis. Microscopic observations on the hairs and hair follicles show a distinct type of invagination of hair shafts within themselves at the zone of beginning keratinization. The process in which the deformity takes place is of relatively short duration, such that it is probable in future cases that it may be encountered only if the defect is searched for in a girl with congenital ichthyosiform erythroderma, who is from approximately one to five years of age. We suggest that, if an eponym is to be assigned to this dermatologic oddity, it be called "Netherton's disease."