Syphilitic alopecia occurs in about 10% of patients with stage II syphilis and can be judged by medical history, symptoms and laboratory tests. 1. Medical history: The patient has a history of stage I syphilis hard chancre. 2. Symptoms: According to the different manifestations of hair loss, it can be classified as syphilitic baldness or diffuse hair loss, both of which can exist at the same time or occur separately. (1) Syphilitic baldness: irregular dotted and patchy hair loss areas with a diameter of 0.3-3cm, mostly on the top of the head, temporal side and occipital area, with unclear boundaries and incomplete hair loss, with uneven and uneven hair lengths, such as insect bites, clinically known as “worm-like alopecia”. “(2) diffuse alopecia: hair loss area is larger, hair thinning, hair loss area skin can have congestive erythema infiltration; (3) other symptoms: can be accompanied by syphilis rash on the extremities, trunk, manifested as dark red rash or maculopapular rash, some patients also with eyebrow, axillary hair, pubic hair loss. 3, laboratory tests: if the syphilis spirochete hemagglutination test (TPHA) and rapid plasma reactin test (RPR) are positive, the diagnosis can be confirmed. Stage II syphilis hair loss local presence of syphilis spirochetes, and the site of syphilis spirochetes and cell infiltration site is basically the same, the hair area by syphilis spirochetes infiltration local microvascular obstruction, poor blood supply, causing hair loss. Syphilis spirochetes do not invade the hair papillae but the upper part of the hair follicles, so incomplete hair loss patches are predominant in syphilis alopecia. However, syphilis alopecia is not permanent hair loss, if treatment is carried out in time, hair can be regenerated within 6-8 weeks, even without treatment.