Female-patterned alopecia in teenage brothers with unusual histologic features

Patterned hair loss, follicular miniaturization, and increased telogen hair counts characterize androgenic alopecia (AGA). Follicular inflammation in AGA has been associated with treatment resistance and progressive hair loss.

Brothers, 15 and 18 years old, presented with frontal and mid-scalp hair loss with an intact frontal hairline noted over a 1-year period. The elder reported past use of androgenic steroids. Laboratory assessment for metabolic and hormonal abnormalities was unrevealing, and hair pull test was negative. Scalp biopsies revealed decreased terminal hairs, marked diameter variation of anagen hairs, decreased terminal to vellus hair ratios (3.7:1/3.4:1, older/younger), and increased telogen counts (23%/21%). Infrabulbar and peri-isthmic (follicular bulge region) lymphocytic infiltrates were present. Hair loss has progressed, unabated by daily topical 0.5% clobetasol (for 6 months), daily 5% minoxidil (1 year), and latter, daily oral finasteride (2 years - older brother only).

Based on patterned hair loss and miniaturized hairs, these brothers have AGA. The female pattern of hair loss (diffuse hair loss affecting the central scalp with preservation of frontal hair line) coupled with follicular isthmic lymphocytic inflammation represents an unusual presentation, possibly a treatment resistant, inflammatory variant of AGA. The differential diagnosis includes exogenous androgen-mediated hair loss, cicatricial pattern hair loss, or the superimposition of alopecia areata.