Alopecia Areata in a Patient Undergoing Treatment for Secondary Syphilis: A Diagnostic Challenge.

A 17-year-old male with a recent history of incarceration and a diagnosis of secondary syphilis presented for follow-up three months after receiving appropriate antibiotic treatment. His venereal disease research laboratory (VDRL) titers showed a favorable decline (from 1:16 to 1:4); however, he reported new-onset patchy scalp alopecia. Clinically, the lesions raised suspicion for syphilitic alopecia (SA). Nevertheless, trichoscopy revealed hallmark findings of alopecia areata (AA), including exclamation mark hairs and black dots, while lacking specific signs of SA, such as an erythematous background. HIV screening was negative. The patient showed significant hair regrowth after six weeks of topical clobetasol. This case highlights that AA can clinically mimic SA, even in patients with active or recent syphilis, and underscores the value of trichoscopy in preventing misdiagnosis and avoiding anchoring bias.