Alopecia syphilitica-report of a patient with secondary syphilis presenting as moth-eaten alopecia and a review of its common mimickers.

Alopecia syphilitica is an uncommon manifestation of secondary syphilis, occurring in only 4 percent of these individuals. It is non-inflammatory and non-cicatricial hair loss that can present in a diffuse pattern, a moth-eaten pattern, or a combination of both. A 38-year-old, otherwise asymptomatic, homosexual man is described whose initial presentation of syphilis was patchy, moth-eaten, alopecia. In addition, differentiating features of alopecia syphilitica and other similar appearing non-cicatricial alopecias are reviewed. Conditions that mimic moth-eaten alopecia include other localized and non-cicatricial alopecias, such as alopecia areata, alopecia neoplastica, tinea capitis, and trichotillomania. The distinguishing clinical and laboratory features of alopecia syphilitica include other mucocutaneous changes associated with secondary syphilis, when present, and a positive serology for syphilis. The treatment of choice is a single intramuscular injection 2.4 million units of benzathine penicillin G for patients without immunocompromise; however, our patient was treated with three weekly doses because of concern about possible HIV positivity. The hair loss usually resolves within 3 months of treatment.