The primary lesion starts as a painless small lump that erodes into a painless ulcer with raised borders.
If untreated the lesion heals, but in 2-8 weeks one can see a generalized red rash that is flat, 2-6 mm in size and can be seen all over the body especially the palms and soles. Simultaneously one may see shallow ulcers with a red border in the mouth and genitals.
These lesions fade and one enters a period when there are no external symptoms for years. (Latent phase)
Subsequently, 5-40 years later one can see involvement of the central nervous system, cardiovascular system, or the skeletal system. Central nervous system symptoms include visual changes, hearing loss, gait disturbance, incontinence, dementia or seizures. Cardiovascular system symptoms include formation of aneurysms of the blood vessels, commonly the aorta. Skeletal system symptoms include destruction of bones.
Congenital syphilis in the neonate is manifested by inflammation of the nasal sinuses – “saddle nose”, development of a rash that peels, bowing of the legs, joint pain and liver failure.