Another Example of Atypical Congenital Triangular Alopecia
Congenital Triangular Alopecia (CTA) is a type of localized hair loss that typically affects the temples. The condition develops in early childhood but may not be present immediately at birth. The key to the diagnosis is the finding of a patch of hair loss in the temples. The shape of the area of hair loss is usually triangular in nature and the pointy aspect of the triangle points upwards to the crown. Trichoscopy shows vellus hairs with no broken hairs or black dots to suggest alopecia areata. The area does not regrow over time.
In 2020, Starace et al reported a series of 78 patients with CTA. In 13 % of cases (10 of 78 patients), the location of hair loss was not the temples. In 5 patients, the CTA was located in the occipital area and in 4 patients it was the parietal area. The location for CTA was the vertex in 1 patient.
SEE: “Congenital Triangular Alopecia = 13 % of the Time It’s Not the Temples”
Shimrada K et al. 2022
A new report by Shimrada and colleagues describes another atypically located CTA in a patient with Down syndrome.
The patient in the report was a 4-year-old boy with Down syndrome who had a patch of non-scarring alopecia since birth. He was first diagnosed with alopecia areata (AA) although hair loss did not improve with topical application of corticosteroids. A triangular-shaped, non-scarring, and non-inflammatory patch of hair loss with accompanying vellus hairs was noted in the leftparietal scalp. Trichoscopy of the area showed white hairs, vellus hair surrounded by terminal hair, and empty follicles. The diagnosis reached was that of congenital triangular alopecia.
