An 8-year-old boy born out of a non-consanguineous marriage presented with localized area of hair loss since the age of 2 years; the patch being persistent since its appearance. There was no history of any trauma or absent skin at birth at the site of alopecia. He had been treated with topical and intralesional steroids by several dermatologists. Examination showed a 3 cm × 2 cm lancet-shaped area of hair loss on the right temporal scalp [Figure 1a]. There was no scaling or erythema. Dermatoscopy showed non-cicatricial patch with predominantly vellus hair [Figure 1b]. Histopathological examination showed normal number of hair follicles, which were predominantly vellus or indeterminate. Inflammation and scarring was not observed [Figure 1c]. In children with patchy hair loss, a common diagnosis to be considered is alopecia areata, which is characterized by peribulbar lymphocytic infiltrate on histopathology and presence of black dots, broken hair, and exclamation hair on dermatoscopy. Trichotillomania can also be considered, where there would be a history indicative of the same.
Figure 1.
(a) Triangular patch of alopecia on the right temporal scalp measuring 3 cm × 2 cm with the tip of the “lancet” pointing superiorly and posteriorly, and the blunt (or wider) end facing inferiorly and anteriorly. (b) Dermatoscopy shows normal follicular openings with predominantly vellus hair in center and terminal hair at the periphery. (c) Histopathological examination of scalp biopsy shows normal number of hair follicles, all of which are vellus or indeterminate. Inflammation and scarring was not observed (H and E, ×100)
In young children with localized non-progressive non-scarring alopecia patch, one must remember to consider congenital triangular alopecia in order to avoid misdiagnosis and mistreatment with intralesional and topical steroids.
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