Background:Syphilitic alopecia is not common in patients with secondary syphilis. Though the clinical and histopathological findings of syphilitic alopecia have been described, the trichoscopy features are unknown yet.Main observation:A 42-year-old Chinese man was admitted to our clinic with a complaint of hair loss. The patient presented clinically with moth-eaten alopecia over the whole scalp without any previous discomfort or skin rashes. The serology for syphilis was positive. Trichoscopy showed black dots, focal atrichia, hypopigmentation of hair shaft and yellow dots.Conclusions:On the basis of trichoscopy, along with serology testing syphilitic alopecia can be differentiated from other hair loss diseases with similar clinical presentation.