Syphilis is one of the most common sexually transmitted diseases (STDs). It is a bacterial infection that spreads through vaginal, oral, or anal sexual contact with someone who has the infection. It can also pass from a pregnant person to their baby.
Syphilis usually develops in stages. Each stage has different signs and symptoms that can last for weeks, months, or even years. In the beginning, the signs and symptoms may be mild. You may not notice them. So, you could have syphilis and not know it. You could pass the infection to someone else.
Syphilis is easiest to cure in the early stages of infection. If it’s not treated and develops to a late stage, it can cause permanent damage to your health. Treatment can still help, but it will not reverse the damage. In rare cases, untreated syphilis can even cause death.
Syphilis tests can help diagnose the infection in the early stages, when it’s easiest to cure. Finding and treating the infection early can also prevent the spread of syphilis to others.
Other names: rapid plasma regain (RPR), Venereal Disease Research Laboratory (VDRL), fluorescent treponemal antibody absorption (FTA-ABS) test, agglutination assay (TP-PA), darkfield microscopy
What are they used for?
Syphilis tests screen for and diagnose syphilis by looking for certain antibodies in your blood. Antibodies are proteins that your immune system makes when it finds harmful substances in your body.
Syphilis testing usually involves two steps. In most cases, the first step is a screening test to check for antibodies that are linked to having a syphilis infection. But other things may trigger your immune system to make these antibodies, such as autoimmune diseases, other infections, and vaccinations.
Screening tests for syphilis usually include:
- Rapid plasma reagin (RPR), which is a blood test.
- Venereal Disease Research Laboratory (VDRL) test, which can be done on blood or spinal fluid
If the result of your screening test shows you have antibodies linked to syphilis infections, you’ll need a second test to confirm whether or not you have syphilis.
Usually, the second test looks for antibodies that your immune system makes only to fight off syphilis. If you have these antibodies, it means you have a syphilis infection now, or you had a syphilis infection that was treated in the past. Common tests to check for syphilis antibodies include:
- Treponema pallidum particle agglutination assay (TP-PA)
- Fluorescent treponemal antibody absorption (FTA-ABS) test
- Micro hemagglutination assay for antibodies to T. pallidum (MHA-TP)
- T. pallidum hemagglutination assay (TPHA)
- T. pallidum enzyme immunoassay (TP-EIA)
- Chemiluminescence immunoassays (CLIA)
Check if you have syphilis
The symptoms of syphilis are often mild and hard to notice. They tend to change over time and may come and go.
Symptoms of syphilis include:
- small sores (ulcers) on your penis, vagina, or around your bottom (anus) – these are usually painless and you may only have one of them
- sores in other areas, including in your mouth or on your lips, hands or bottom
- white or grey warty growths most commonly on your penis, vagina or around your anus
- a rash on the palms of your hands and soles of your feet that can sometimes spread all over your body – this is not usually itchy
- white patches in your mouth
- flu-like symptoms, such as a high temperature, headaches and tiredness
- swollen glands
- patchy hair loss on the head, beard and eyebrows
It can take 3 weeks or more for the symptoms of syphilis to appear after you’re infected.
Sometimes the symptoms can improve or go away completely, but if you have not been treated the infection is still in your body.
Other ways to get a syphilis test
You can also have a syphilis test:
- during a pregnancy (antenatal) appointment, if you’re pregnant
- using a self-test kit – you may be able to order a kit online from your local STI testing and treatment service or buy one from a pharmacy
You use a self-test kit at home and send it to a lab to be tested.
Why do I need a syphilis test?
You should get tested for syphilis if you have symptoms of syphilis or if your sexual partner was recently diagnosed with syphilis. Symptoms usually appear about two to three weeks after infection and include:
- Small, painless sore (chancre) on the genitals, or in the mouth, anus, or rectum
- Rough, red rash, usually on the palms of the hands or the bottom of the feet
- Headache or muscle aches
- Sore throat
- Swollen glands
- Weight loss
- Hair loss in patches
Even if you don’t have symptoms, you should get tested regularly if you have a high risk for getting syphilis. You’re more likely to get syphilis if you have:
- Multiple sex partners
- A partner with multiple sex partners
- Unprotected sex (sex without using a condom)
- An HIV infection and are sexually active
- Another sexually transmitted disease, such as gonorrhea
- Sex with men who have sex with men (MSM)
Ask your provider you how often you should get tested.
You will also need a syphilis test if you are pregnant. If you pass it to your baby, it could cause serious, and sometimes deadly, health problems in the baby.
The Centers for Disease Control and Prevention recommends that all pregnant people have a syphilis test at their first prenatal visit. Pregnant people who are more likely to become infected with syphilis should be tested again at 28 weeks of pregnancy and at delivery.
What happens during a syphilis test
If you have symptoms of syphilis, a doctor or nurse will check your penis, vagina and bottom (anus) for syphilis sores (ulcers). They may use a swab (like a cotton bud) to collect a fluid sample from any sores.
They’ll also check the rest of your body for other signs of syphilis like a rash, sores or wart-like growths. They may also take a blood sample.
You may also have tests for other sexually transmitted infections (STIs) at the same time.
Complications of syphilis
If it’s not treated, syphilis can cause serious and potentially life-threatening problems including:
- heart problems like angina, aortic aneurysm and heart failure
- brain problems like fits (seizures), memory problems, personality changes and dementia
- nerve problems like shooting pains, pins and needles, joint pain and gradual damage the joints
- problems with the skin, bones, testicles, liver and any other organ
Some of these problems may not appear for many years after being infected with syphilis.
Syphilis during pregnancy
If you’re pregnant and have syphilis, you can pass it on to your baby before they’re born. This is known as congenital syphilis.
Having syphilis during pregnancy can also increase your risk of miscarriage, premature birth and stillbirth.
You’ll be offered screening for syphilis if you’re pregnant so it can be found and treated before it causes any serious problems.
Will I need to do anything to prepare for the test?
You don’t need any special preparations for a syphilis blood test. For a lumbar puncture, you may be asked to empty your bladder and bowels before the test.
Are there any risks to the test?
There is very little risk to having a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.
If you had a lumbar puncture, you may have pain or tenderness in your back where the needle was inserted. You may also get a headache after the procedure. The headache may last from a few hours to more than a week.
What do the results mean?
If your screening test results are negative (normal), it means you probably don’t have a syphilis infection. But after getting infected, antibodies can take a couple of weeks to develop. So you may need another screening test if you think you were exposed to syphilis. Your provider can tell you whether you need another test.
If your screening test results are positive, it means you have antibodies that may be from a syphilis infection. You’ll need another test to confirm whether or not you have syphilis.
If your follow-up test confirms you have syphilis, you will probably be treated with penicillin, a type of antibiotic. Antibiotic treatment completely cures most early-stage syphilis infections. Later-stage syphilis is also treated with antibiotics, but this treatment can’t undo any damage that the syphilis caused.
When diagnosed and treated in its early stages, syphilis is easy to cure. The preferred treatment at all stages is penicillin, an antibiotic medication that can kill the organism that causes syphilis. If you’re allergic to penicillin, your doctor may suggest another antibiotic or recommend penicillin desensitization.
The recommended treatment for primary, secondary or early-stage latent syphilis — which refers to an infection within the last year — is a single injection of penicillin. If you’ve had syphilis for longer than a year, you may need additional doses.
Penicillin is the only recommended treatment for pregnant women with syphilis. Women who are allergic to penicillin can undergo a desensitization process that may allow them to take penicillin.
Even if you’re treated for syphilis during your pregnancy, your newborn child should be tested for congenital syphilis and if infected, receive antibiotic treatment.
The first day you receive treatment, you may experience what’s known as the Jarisch-Herxheimer reaction. Signs and symptoms include a fever, chills, nausea, achy pain and a headache. This reaction usually doesn’t last more than one day.
After you’re treated for syphilis, your doctor will ask you to:
- Have periodic blood tests and exams to make sure you’re responding to the usual dosage of penicillin. Your specific follow-up will depend on the stage of syphilis you’re diagnosed with.
- Avoid sexual contact with new partners until the treatment is completed and blood tests indicate the infection has been cured.
- Notify your sex partners so that they can be tested and get treatment if necessary.
- Be tested for HIV infection.
Is there anything else I need to know about syphilis tests?
If you are diagnosed with syphilis, you need to tell anyone you’ve had sexual contact with so that they can get tested and treated if necessary. You will likely need repeat syphilis screening tests to see how well your treatment is working. Avoid sexual contact with others until testing shows you are cured.