Alopecia Areata With an FFA-Like Phenotype: Clinicopathologic Features and Treatment Outcomes in a Prospective Cohort

Although alopecia areata (AA) typically presents as focal patches, it may manifest as hairline alopecia. We previously described an unusual AA presentation characterized by frontotemporal hairline recession with isolated single hairs.

Fifty-six patients with frontotemporal hairline recession and isolated single hairs were prospectively enrolled. Clinical, trichoscopic, and histopathologic features were characterized. Treatment outcomes were described by Severity of Alopecia Tool (SALT) score changes at months 3 and 6 and categorical status at last follow-up; 3 month corticosteroid response was compared with matched patchy AA controls.

Patients (62.5% female; mean age 30.4 years) had a mean disease duration of 6.5 years and a mean baseline SALT score of 29.0. More than half had prior patchy AA. Trichoscopy consistently showed a predominance of 1-hair follicular units at the hairline. In biopsied cases, histopathology showed preserved pilosebaceous units, markedly increased telogen follicles, and residual solitary terminal hairs, without perifollicular fibrosis or lichenoid inflammation. Among 30 patients with evaluable outcomes, the median percent change in SALT score was 0% at Month 3 and 18.4% at Month 6. At the last evaluable follow-up, 6 patients (20.0%) achieved significant improvement. In the matched analysis, this phenotype showed a lower 3 month SALT₅₀ response to systemic corticosteroids than patchy AA (5.9% vs. 76.5%; p < 0.001).

This expanded cohort characterizes a frontal fibrosing alopecia (FFA)-like phenotype within the AA spectrum, supported by a non-scarring histopathologic profile in biopsied cases. Follow-up data suggest an insidious, chronic course and limited scalp hair regrowth among treated patients.