Stage I syphilis is mainly manifested as a hard chancre, which is a nodule or ulcer on the external genitalia with no obvious symptoms that appears 2-4 weeks after the adult is infected with syphilis. Stage II syphilis is mainly manifested by skin and mucous membrane damage. After 5-8 weeks, superficial, transient red rashes, papules or macules may appear on the skin and mucous membranes of the body. Stage III syphilis can occur in any part of the body, and the skin and mucous membranes can show nodular syphilis rash, skin dendrites, mucosal destruction, bone damage, cardiovascular syphilis, neurosyphilis, etc.