Syphilis can occur in the penis, glans, coronal sulcus, foreskin and urethra in men, and in the labia, clitoris and cervix in women, and in the anus, anal canal, lips, tongue and breasts in some patients. Syphilis is mainly characterized by syphilis rash, which can occur in the skin and mucous membrane damage, and even bone and joint and neurological syphilis. 3. In stage III syphilis, skin and mucous membrane damage, nodular syphilis rash occurs on the scalp, scapula and extremities, mainly on the extensor side. 4. Gum-like swelling can occur in the lower legs, and some nodules near the joints can also occur, and some patients can develop cardiovascular and neurological syphilis in the late stage.