A syphilis rash is a topical skin condition caused by the sexually transmitted infection (STI) syphilis. This rash is the key symptom of the infection’s second stage. For this reason, it’s sometimes called a secondary syphilis rash. The rash develops after a painless bump appears at the site where the syphilis bacteria enter the body, usually on the genitals or mouth. Over time, this bump forms an ulcer, known as a chancre.
What Causes a Syphilis Rash?
A syphilis rash is a common symptom of syphilis. This infection is caused by Treponema pallidum bacteria.
You can get syphilis and develop a syphilis rash if you have sexual contact with syphilis ulcers on an infected partner’s genitals, anus, or mouth. Nonsexual contact such as sharing food or eating utensils, wearing an infected person’s clothes, opening common doors, swimming in the same pool, or sitting on the same toilet seat will not spread syphilis.
Expectant mothers with syphilis can also pass the infection on to their babies. Pregnant women with syphilis are more likely to deliver early and have stillborn babies. Babies born to mothers with syphilis may have health problems including seizures, deafness, cataracts, and even premature death. Because syphilis can be so dangerous for new or expectant moms and their babies, pregnant women are strongly encouraged to get tested for syphilis. Early treatment can prevent these serious problems.
How Does a Syphilis Rash Develop?
If you don’t get treatment when a syphilis chancre develops, a syphilis rash will appear two to 12 weeks later. It may develop after the chancre has cleared or while it is still present on the skin.
A syphilis rash usually has a rough finish and raised red- to brown-colored spots; however, it might also be smooth. It typically appears on the bottom of your feet or the palms of your hands, but it can occur anywhere on the body. A syphilis rash might also be made up of large, raised gray to white lesions with a moist finish. These types of syphilis rashes occur on the inner thighs, armpits, groin, or below the breasts. Because syphilis rashes are very pale and not itchy or painful, they can be easy to overlook.
What Other Symptoms Accompany a Syphilis Rash?
A range of other flu-like symptoms usually accompanies a syphilis rash. These symptoms include:
- Patchy hair loss.
- Red and irritated mucous membranes in the mouth, throat, genitals, and anus.
- Fever and chills.
- Swollen lymph nodes.
- Sore throat.
- Lesions in mucous membranes, including the mouth, throat, nostrils, anus, and vagina.
- Achy muscles.
- Weight loss.
How Do You Prevent a Syphilis Rash?
Reducing your risk of contracting syphilis in the first place is the best way to prevent a syphilis rash. You can do this by using condoms and dental dams whenever you have vaginal, anal, or oral sex. A condom or dental dam will provide a barrier that prevents your body from touching syphilis sores. However, they won’t help if your partner has sores these devices don’t cover.
Regular STI testing will also help you learn whether you or your partner has syphilis. This is a good option, as syphilis chancres and rashes can be otherwise difficult to detect.
Seeking medical treatment early will ensure you don’t enter the second stage of syphilis and develop a rash. Get tested regularly, and check your body for chancres between testing.
How Do You Diagnose a Syphilis Rash?
Your healthcare provider might suspect you have a syphilis rash during a physical exam, but you’ll need an STI test to confirm the diagnosis. Medical professionals usually diagnose syphilis by testing blood for antibodies that occur in response to the presence of T. pallidum. You can order a kit to test for syphilis and other STIs easily and confidentially from Nurx™.
How Do You Treat a Syphilis Rash?
Your care provider will usually administer a shot of benzathine penicillin to clear up your syphilis rash and eradicate the bacteria from your system. It should take just one dose to clear syphilis from your system when it’s in the secondary stage.
If you’re allergic to penicillin, your medical team might prescribe other medications, such as doxycycline or tetracycline. As these are not the preferred treatments, your medical team will monitor you closely and conduct follow-up testing to ensure you’re clear of syphilis.
Avoid having sex until your syphilis rash and any sores have healed completely. It’s also a good idea to notify any recent sexual partners of your diagnosis so they can check if they have syphilis, too.
What Happens if a Syphilis Rash Goes Untreated?
A syphilis rash will disappear on its own, without treatment, but the infection that caused it will not. Once a syphilis rash fades without treatment, you will enter the third phase of syphilis, sometimes known as the dormant or latent stage. This stage can last for years. During this time, the bacteria typically lie dormant in the body. The infection does not cause any symptoms in this stage.
Some people have latent syphilis for their entire lives. However, in rare cases untreated syphilis can enter a very serious final stage. This can occur 10 to 30 years after the initial syphilis infection. The symptoms of late-stage syphilis are very severe, so it’s important to seek medical treatment before you get them. They can include:
- Nerve damage.
- Difficulty coordinating thoughts and movements.
- Dulled senses.
- Vision problems, including blindness.
- Heart problems.
- Damage to blood vessels.
- Impaired liver function.
- Damage to joints and bones.
Syphilis treatment is accessible and affordable, though, so there is no need to let the infection progress to this critical final stage.
Syphilis – CDC Fact Sheet (Detailed), Centers for Disease Control and Prevention, January 2017