After an incubation period that generally lasts about 3 weeks, symptoms of primary syphilis develop.

Initially, one or more chancres (small, fluid-filled lesions) erupt on the genitalia; others may erupt on the anus, fingers, lips, tongue, nipples, tonsils, or eyelids. These chancres, which are usually painless, start as papules and then erode; they have indurated, raised edges and clear bases.

Chancres typically disappear after 3 to 6 weeks, even when untreated. They are usually associated with regional lymphadenopathy (unilateral or bilateral). In women, chancres are frequently overlooked because they often develop on internal structures—the cervix or the vaginal wall.

The development of symmetrical mucocutaneous lesions and general lymphadenopathy signals the onset of secondary syphilis, which may develop within a few days or up to 8 weeks after the onset of initial chancres.

The rash of secondary syphilis can be macular, papular, pustular, or nodular. Lesions are of uniform size, well defined, and generalized. Macules often erupt between rolls of fat on the trunk and on the arms, palms, soles, face, and scalp. In warm, moist areas (perineum, scrotum, vulva, between rolls of fat), the lesions enlarge and erode, producing highly contagious, pink or grayish white lesions (condylomata lata). Even without treatment, rashes clear up on their own.

Mild constitutional symptoms of syphilis appear in the second stage and may include headache, malaise, anorexia, weight loss, nausea, vomiting, sore throat and, possibly, slight fever. Alopecia may occur, with or without treatment, and is usually temporary. Nails become brittle and pitted.

Although no clinical symptoms occur in latent syphilis, it produces a reactive serologic test for syphilis. Because infectious mucocutaneous lesions may reappear when infection is of less than
4 years’ duration, early latent syphilis is considered contagious.