Primary Stage:
A skin lesion, called a chancre, is the first sign of a syphilis infection. Chancres appear at the location where T. pallidum entered the body anytime from 10-90 days after infection, with an average onset of 21 days post-infection. In approximately 40% of cases, only a single, firm, round, and painless chancre of approximately 0.3-3 cm occurs.
In others, multiple chancres appear that may be painful and tender. Chancres generally occur on the cervix for women (44% of cases), penis for heterosexual men (99%), and anally and rectally for men who have sex with men (34%). In 80% of cases, lymph node swelling in the area of the infection also occurs. Chancres last for three to six weeks and heal whether or not treatment is received. If untreated, the infection progresses to the secondary stage.
Secondary Stage:
Skin rashes and/or lesions in the mouth, vagina, or anus occur during the secondary stage of infection. These may appear when the primary chancre is healing or several weeks after it has healed. In addition, many individuals who present with the later secondary symptoms either do not develop a chancre or the chancre is unnoticed. Syphilis rashes vary in appearance, and can include rough red spots on the palms, large, raised, gray or white lesions (condyloma lata) in the mouth, underarm or groin, or rashes that are so faint that they are unnoticed. Additional symptoms in the secondary stage can include fever, sore throat, hair loss, weight loss, swollen lymph glands, headaches, muscle aches, and fatigue. Rare complications include inflammation of the liver, joints, and optic nerve, kidney disease, and interstitial keratitis. Like the primary symptoms, secondary symptoms will also disappear whether or not treatment is received. However, the syphilis infection will progress to the latent stage if adequate treatment does not occur.
Latent Stage:
There are no visible signs or symptoms of syphilis during the latent (hidden) stage. However, syphilis-causing bacteria (T. pallidum) are still present. In the early latent phase (less than two years after original infection), transmission can still occur as up to 25% of individuals can develop a recurrent secondary infection. Individuals are not as infectious in the late latent phase (more than two years after the original infection). The latent stage can last for many years, with 15-40% of untreated individuals developing tertiary syphilis.
Tertiary Stage:
The potentially fatal tertiary stage can occur 10-30 years or more after acquiring a syphilis infection. Multiple different organ systems can be affected including the brain, nerves, eyes, heart, liver, bones, and joints. The associated symptoms vary depending on the affected body parts.
Neurosyphilis and Ocular Syphilis:
At any stage of infection, T. pallidum can invade the nervous system causing neurosyphilis, or the eyes causing ocular syphilis. Neurosyphilis symptoms can include headaches, paralysis, dementia, sensory deficits, and altered behavior. Ocular syphilis can cause vision changes, decreased visual acuity, and blindness.