[Syphilis].
In Japan, the incidence of syphilis has decreased, and clinicians might be more likely to overlook syphilis than before. We show typical clinical manifestations and treatment of syphilis for clinicians unfamiliar with the disease and emphasize that two types of serologic test, non treponemal tests and specific treponemal tests, are essential for diagnosis of syphilis. Recent automated serologic tests for syphilis are useful to examine patients' progress after they are treated. The early stage of syphilis is gradually spreading among men in Japan, and HIV coinfections are often caused by homosexual contacts. We present a sample figure in the classic medical book, "Atlas of syphilis and the venereal diseases".