Symptoms

Syphilis can cause a range of symptoms or none at all, but if left untreated can have very serious effects on the brain and the rest of the nervous system (known as neurosyphilis).

In HIV-negative people, initial infection with syphilis (primary syphilis) may cause a chancre (an ulcer, sore or spot) at the site of infection, usually in the genital region. This does not hurt and heals after a couple of months. The chancre is usually accompanied by swollen glands.

In HIV-positive people chancres can appear as unusual or multiple ulcers, and may be mistaken for an attack of genital herpes. People with HIV are more likely to be diagnosed when syphilis has reached the secondary stage than HIV-negative people.

Secondary syphilis can cause symptoms of rash, swollen glands, warts, various constitutional symptoms and, less frequently, other symptoms such as meningitis. More sores may occur, especially on the hands and feet.

Neurosyphilis can occur at any stage of syphilis. Syphilitic meningitis and meningovascular syphilis occur early, within the first few years of infection. General paresis and tabes dorsalis occur later, typically five to 30 years after infection. In addition to neurosyphilis, late syphilis can cause lesions in almost any organ of the body.

A US review of cases of neurosyphilis in HIV-positive people found that the most commonly reported symptoms were visual disturbances (51%); headache (32%); difficulty walking (4%); and hearing loss (4%).¹

At the time of neurosyphilis diagnosis, 47% had secondary syphilis, 10% had signs of secondary syphilis within a week of neurosyphilis diagnosis, 24% had "early latent" syphilis, and 18% had “late latent” syphilis.

One in four had had a previous history of syphilis, although nine (of twelve) had “adequate” previous penicillin treatment documented, and six had clinical notes suggesting they had an appropriate response to treatment. The investigators estimated the risk of an HIV-positive gay man with early syphilis having symptomatic early neurosyphilis was 1.7% (40 of 2380), or one in 59.

In addition, they estimate the risk for having neurosyphilis with persistent symptoms six months after treatment was 0.5%, or one in 200.

In people with HIV the course of the disease may be different. There seems to be an increased risk of brain involvement, and unusual symptoms may include skin and mouth ulcers and fever. It is also possible that HIV speeds up the course of syphilis: several recent studies have shown that syphilis can lower CD4 cell counts and raise viral loads in HIV-positive men.^{2 3}