Clinical analysis of 10 cases of congenital triangular alopecia / 中华皮肤科杂志

ABSTRACT

Objective:To investigate clinical features of congenital triangular alopecia.Methods:Clinical data were collected from 10 children with congenital triangular alopecia, who were diagnosed and treated in Xiamen Children′s Hospital from August 2020 to June 2021, and their clinical and dermoscopic features were analyzed.Results:All the 10 patients were males, aged from 2 months to 6 years and 4 months. Hair loss occurred at birth or within 1 month after birth in 6 children, and occurred between the age of 4 months and 6 years in 4. The alopecic area was located in the left frontotemporal region in 5 patients, in the right frontotemporal region in 3, and in the vertex region in 2. In all the patients, thin vellus hair could be seen in the alopecic areas, and the hair pull test was negative, while in 1 patient showed some normal terminal hair scattered in the alopecic area. Dermoscopy showed a lot of vellus hair surrounded by normal terminal hair in the alopecic area with a clear boundary, and no yellow or black dots, or 'exclamation mark’ hair was observed. Seven patients had visited department of dermatology due to hair loss, of whom 5 were diagnosed with alopecia areata, and 2 with sebaceous nevus.Conclusions:Congenital triangular alopecia is common in children, and mostly occurs in the left frontotemporal region. It is characterized by the replacement of normal terminal hair by thin vellus hair in the alopecic area. Dermoscopy is helpful in its diagnosis and differential diagnosis.