Familial occurrence of follicular keratosis of the chin

Abstract

A peculiar cutaneous disorder in children characterized with a presentation of multiple, closely set, hyperkeratotic follicular papules on the chin was first reported in 1972 by Arai 1 as 'a kind of follicular nevus', while, in 1979, Padilha-Goncalves 2 reported a similar condition and proposed the term 'traumatic anserine folliculosis (TAF)'. They described the stressing etiologic factors such as prolonged friction or pressure, the goose skin appearance, and follicular location of the lesions. Since then, this skin disorder has been called keratotic papular lesions on the chin 3 or follicular keratosis of the chin (FKC). [4][5][6][7] The lesions occurred mostly in children and teenagers. Usually, boys are affected, but girls are also affected by FKC.According to a paper 8 on the clinico-epidemiological profile of 26 patients with FKC, 19 were male and 7 were female (the male to female ratio, 2.7:1); the most commonly affected age group was 8-14 years in 22 (84.6%) children; and, history of friction or pressure was recalled by 16 patients while 10 patients did not remember.The most probable etiology of FKC currently accepted is that the patients have a habit to rest their chin on their palms while reading or watching television. Indeed, Kanzaki et al. 5 reported two cases whose FKC were induced by such a habit and slowly resolved after they avoided it. However, FKC was also reported in patients, including siblings, 7 without any evidence of the mechanical trauma over the chin, 7,9 suggesting the etiologies other than the physical trauma for the development of FKC.In the present study, we report two brothers with FKC who did not have any evidence of physical trauma over the chin. | C A S E REP ORTSA 7-year-old Japanese boy and his 9-year-old brother presented with papular lesions on the chin that had appeared 6 months and 3 months previously in the younger and older brother, respectively. Whitish-yellow creamy contents were often squeezed out from the top of papules in the younger brother. The children and their mother denied any habitual physical trauma over the chin. Their medical histories were unremarkable.