What to Know About the Symptoms and Treatment of Syphilis

Over the past five years, cases of syphilis — a bacterial infection that is primarily spread through sexual contact and can be passed from a pregnant person to a baby during pregnancy — have surged in the U.S., up 80% between 2018 and 2022, according to recent data from the Centers for Disease Control and Prevention (CDC). Congenital syphilis, which occurs when the infection is transmitted from mother to baby, has also become 10 times more common in the past decade.

When left untreated, syphilis can lead to serious health risks. “We’re seeing dramatic rises in syphilis and congenital syphilis, so we have to do something differently,” says Dr. Jason Zucker, an infectious disease physician at NewYork-Presbyterian/Columbia University Irving Medical Center.

Recently the first at-home, over-the-counter blood test for syphilis was approved by the Food and Drug Association (FDA). The new test detects antibodies, which are proteins in the blood that fight viruses and bacteria. A positive test would indicate that the body has responded to syphilis representing either a current or past infection. It’s done with a finger prick, and results are provided in approximately 15 minutes.

“The test does not replace office-based testing for syphilis, so you need to follow up with a provider,” says Dr. Zucker. “But for people who may be nervous or anxious, it’s a great starting point to test in the privacy of your own home.”

Health Matters spoke to Dr. Zucker about syphilis testing and what to do if you have an infection or think you’ve been exposed.

What are the symptoms of syphilis?
About three weeks after infection, the first sign of syphilis (primary syphilis) is a small sore, and it’s painless. It appears where the bacteria contacted your body. Many people don’t notice the sore because it can be hidden, for example, in the vagina, the base of the penis, the rectum, or the throat. The sore heals on its own within about three to six weeks. Then, you can develop a rash (secondary syphilis), which is also painless and goes away after a couple of days. Other common early symptoms include fever, swollen lymph nodes, and weight loss.

Is the at-home test the same one you get in the doctor’s office?
It’s not the same. At the office, we do a series of tests to confirm syphilis, including several different antibody tests. The at-home test is great for people who’ve never been diagnosed with syphilis before, but it’s not definitive. It only checks for your body’s response to syphilis, not the bacteria itself. We screen for quantitative antibodies that can help us determine if it is a current or past syphilis infection. There are also tests available where you can swab a sore and send the fluid to a laboratory to confirm syphilis, but those are not widely used. Sores from syphilis appear early in the infection and then disappear. So the timing has to be right in order to use the swab test.

Are the at-home tests accurate if you use them right after you’ve been exposed?
It’s not like a COVID test where you immediately use it because the incubation period for syphilis is long. You can turn positive for syphilis from seven to 90 days after a sexual encounter. So this test is helpful if you have never been screened or may have been recently exposed.

Do you think the at-home test will help curb the rise in syphilis?
It’s good news that people have another choice, however the at-home test has limitations so it’s incredibly important for people to do regular screenings for syphilis at a doctor’s office or health clinic, especially when you are sexually active. For people who are nervous or hesitant about coming in, the at-home test can help start your testing journey.

Is it possible to have syphilis for years and not know it?
Because the early symptoms of syphilis self-resolve and are painless, it can stay in the body for years before causing other complications. And if you don’t know you have syphilis, you can also transmit it to partners, including partners who may become pregnant and that can lead to congenital syphilis.

How do you treat syphilis?
Penicillin works well to cure it. If the infection has progressed to the late stage, the antibiotic cannot reverse the damage, but it will stop it from getting worse.

What are the long-term health risks associated with syphilis?
It can cause permanent decreases or loss of vision and permanent decreases in loss of hearing. That can happen both in early syphilis, but it can also happen in something called late syphilis or tertiary syphilis, which is years and years down the line. In the most severe cases, it can cause damage to the heart, brain and nervous system.

What do pregnant people need to know about congenital syphilis?
A pregnant person can pass syphilis to the baby through the placenta. It’s important to get tested for syphilis as early as possible, at the first prenatal visit, because it is treatable with an antibiotic which significantly reduces the risk for babies. You should also be tested later in pregnancy given the long incubation period and because you can acquire syphilis during pregnancy. Left untreated, congenital syphilis can cause organ damage, anemia, and even stillbirth or infant deaths.

Why do you think cases of syphilis and congenital syphilis are increasing?
There are many reasons. I think in some ways people forgot about syphilis for a long time. We were really, really close to eliminating it and then it just surged dramatically. To control the epidemic, we need to make sure we reinvest in our public health infrastructure and sexual health clinics and make sure routine screening is offered and conducted.

How can stay protected from getting syphilis?
I think the most important thing is for providers to discuss with patients what works best for them to prevent sexually transmitted infections — whether that’s condoms, regular testing and treatment, or medications. Choosing a prevention method that is congruent with your lifestyle is the best way to protect yourself.