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

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.

Five Cases of Congenital Triangular Alopecia / 대한피부과학회지

Congenital triangular alopecia has been reported as a rare form of focal hair loss, characterized by a triangular patch of permanant alopecia on the frontoparietal area of the scalp, present from birth. However, it shows diverse clinical spectra of onset, shape and location and, furthermore, it may not be as rare as previously thought. Therefore, in order to avoid inappropriate management, it is very important to differentiate it from preclinical nevoid entities such as epidermal nevus, aplasia cutis and, especially, alopecia areata. We herein report five cases of congenital triangular alopecia.

A Case of Congenital Triangular Alopecia in Infancy / 대한피부과학회지

Congenital triangular alopecia is an uncommon nonscarring form of alopecia. It presents with isolated alopecic patch at the frontotemporal area of the scalp. Although previously considered congenital, this condition usually is discovered after 2 years of age and, more recently, is thought to be acquired. We report a case of congenital triangular alopecia in a 12 month old female who had the lesion since birth.

Congenital Triangular Alopecia / 대한피부과학회지

Congenital triangular alopecia is a rarely reported idiopathic congenital circumscribed alopecia. It presents with isolated patches of permanent alopecia involving the frontotemporal suture area of the scalp. It is necessary to differentiate it from other conditions such as alopecia areata in order to avoid prolonged treatment which may cause adverse side effects. We report a case of 7-year-old boy with congenital triangular alopecia.