Syphilis facts

What is syphilis

Syphilis is a sexually transmitted infection (STI) caused by a type of bacteria called Treponema pallidum. It can spread from person to person by physical contact during vaginal, anal, or oral sex. Usually, symptoms show up 2-12 weeks after being exposed to syphilis.

Symptoms of syphilis

Possible early symptoms: (2-12 weeks after becoming infected). This is called primary syphilis.

• A sore called a chancre. There may be more than one. They are usually not painful. They may be on the penis, scrotum, vaginal lips, anus, or mouth. You may not notice these sores if you cannot see them or feel them because they can be inside the vagina, mouth or anus. Even without treatment these sores will go away after several weeks, but you will still be infected and can infect sex partners.
• Lymph glands near the sore may be swollen but not painful.

Possible later symptoms: (4-12 weeks after becoming infected). This is called secondary syphilis.

• Flu-like illness with sore throat, headache, and fever.
• Skin rash all over the body and sometimes on the palms of the hands and soles of the feet (not itchy).
• Any rash on the genitals.
• Warty-like growths may appear on the genitals or around the anus.
• Grayish/whitish patches may appear on the tongue or throat along with sore throat.
• Patchy hair loss may be noticed.
• Nervous system symptoms: neck stiffness, nausea, vomiting, seizures, hearing loss and a red, painful eye. Even without treatment these symptoms will go away after several weeks, but you are still infected and can infect sex partners.

How to check if you have syphilis

• If you have a sore on your genitals, your anus or have a skin rash, have an STI check. There are special tests available at City Clinic to diagnose syphilis on the day of your visit.
• Oftentimes, syphilis can go unnoticed but a blood test would confirm it.

How dangerous is syphilis

• Syphilis may infect the brain, eye and ear resulting in severe headache, stiff neck, seizures, a painful, red eye with decreased vision or hearing loss.
• Pregnant women with syphilis can pass the infection to the baby which can cause many health problems for the baby.
• Syphilis and HIV are commonly found together. The sores of primary syphilis can make it easier for HIV to be passed to or from a partner.
• If you have syphilis and are HIV negative, you will be offered an HIV test at the same time your syphilis is diagnosed. If your test is negative, please talk to your provider about pre-exposure prophylaxis (PrEP).
• If you are HIV positive and not on HIV medication, syphilis could worsen your HIV disease.

How to treat syphilis

• Penicillin cures syphilis. Another medicine can be used if you are truly allergic to penicillin.
• We sometimes diagnose syphilis in persons who are no longer sexually active. They could have been infected many years ago. We recommend treatment for them because some people with long term, untreated syphilis can develop brain, heart, and nervous system damage. At this late stage of syphilis, a person is not contagious to sex partners.

What to do if you have syphilis

• Your sex partner(s) should be examined and treated. If not treated, they can give the infection back to you, or infect others.
• Your syphilis blood test may stay positive (not normal) even after treatment. You are no longer contagious once treatment is completed. Please let any health care providers that test you for syphilis from now on know you have been treated in the past.
• You will need to be evaluated three months after treatment, and then regularly during the first year of your diagnosis and treatment. This would include an exam and blood tests.

What to expect if you are diagnosed with syphilis

A Department of Public Health Disease Control Investigator will contact you. They will help you better understand your infection and provide you with information needed to protect your future health and help get your partners treated.

How to avoid getting syphilis

• Condoms are effective in reducing the risk of infection.
• Ask your health care provider about doxy-PEP.
• Do not have sex if you or a sexual partner has symptoms of an STI, including discharge, burning with urination, rash, or genital sores.

This information is provided by San Francisco City Clinic.

Visit our homepage at sf.gov/cityclinic.

Information last revised January 2024