Syphilis often gives no obvious signs, which is why many people carry it without realizing. When symptoms do appear, they follow a predictable pattern of stages, each looking quite different from the last. The only way to know for certain is a blood test, but understanding what to watch for can help you catch it early, when treatment is simplest.
The First Sign: A Painless Sore
The earliest symptom of syphilis is a sore called a chancre that appears where the bacteria entered your body. These sores show up on or around the genitals, anus, rectum, lips, or inside the mouth. What makes them easy to miss is that they’re typically firm, round, and painless. They don’t burn or itch the way you’d expect an infection to feel.
You might notice a single sore or several. They develop roughly three weeks after exposure, though the timing can range from 10 to 90 days. The sore lasts about 3 to 6 weeks and then heals on its own whether or not you get treated. This is deceptive: the infection hasn’t gone away, it’s just moved deeper into your body. Because the sore is painless and sometimes hidden inside the mouth, vagina, or rectum, many people never notice it at all.
How Syphilis Sores Differ From Herpes
A sore in your genital area can be alarming, and it’s natural to wonder whether it’s syphilis, herpes, or something else. The two look and feel quite different. A syphilis chancre is usually firm, round, and painless. A herpes outbreak typically involves clusters of small red bumps or blisters that are painful or itchy, often with tenderness in the surrounding skin. Herpes sores can also make urination painful, which syphilis sores generally don’t.
That said, visual appearance alone isn’t reliable enough to tell the difference. Sores can look atypical, and it’s possible to have more than one STI at the same time. A blood test or a swab of the sore itself is the only way to get a definitive answer.
The Second Stage: A Rash and Flu-Like Symptoms
If syphilis isn’t treated during the first stage, it progresses to a second stage that looks very different. The hallmark is a rash, often rough and discolored, that can appear anywhere on the body. What’s distinctive is that it frequently shows up on the palms of the hands and the soles of the feet, locations most other rashes don’t affect. The rash usually doesn’t itch, which is another reason people don’t immediately connect it to an infection.
Along with the rash, you may feel run down in ways that mimic the flu: fever, sore throat, swollen lymph nodes, fatigue, muscle aches, headaches, or patchy hair loss. These symptoms can come and go over a period of weeks or months. Because they overlap with so many common illnesses, secondary syphilis is sometimes called “the great imitator.” People may chalk it up to a virus or allergies and never get tested.
The Silent Stage: No Symptoms at All
After the second stage resolves, syphilis enters what’s called the latent stage. During this period, there are zero symptoms. You feel completely fine. The bacteria are still in your body, and you can still pass the infection to others during the early part of this stage, but nothing visible or physical tips you off. This latent period can last years, even decades.
This is the stage where syphilis is most commonly missed. Without screening, there’s simply no way to know you have it. Many people are diagnosed only because they happened to get a routine blood test for another reason.
Late-Stage Damage to Organs and the Nervous System
Without treatment, a portion of people with latent syphilis eventually develop serious complications years or decades later. Late-stage syphilis can damage the heart, blood vessels, brain, and other organs.
When syphilis spreads to the nervous system, it can cause a range of neurological problems: severe headaches, difficulty coordinating movement, numbness, changes in mental status, confusion, or stroke. When it affects the eyes, it can cause blurred vision, eye pain, or sensitivity to light, and may lead to permanent blindness. When it reaches the inner ear, it can cause sudden hearing loss, ringing in the ears, or vertigo. Hearing loss from syphilis can be permanent and may come on rapidly.
These complications are preventable. Syphilis is highly treatable in its early stages. The reason late-stage damage happens is almost always because the infection went undetected for too long.
How Syphilis Testing Works
Syphilis is diagnosed with a simple blood test. The standard approach uses two types of tests together. One detects general antibodies your immune system produces in response to infection. The other looks for antibodies specific to the syphilis bacterium. Both are needed because one test alone can sometimes produce a false positive or fail to distinguish a current infection from one that was treated in the past.
If you have an active sore, a provider can also swab it directly to look for the bacteria. This can confirm a diagnosis even before blood antibodies have built up.
Timing matters. A blood test taken too soon after exposure may come back negative even if you’re infected. Most infections are detectable by one month after exposure. By three months, nearly all cases will show up on a blood test. If you had a specific exposure you’re concerned about, testing at both the one-month and three-month marks gives you the most reliable answer.
At-Home Tests vs. Clinic Tests
At-home syphilis testing kits are available and involve a finger-prick blood sample you mail to a lab. The tests themselves are generally reliable, but accuracy depends heavily on how well you collect the sample. A poorly collected sample can lead to a false negative, meaning the test says you’re fine when you’re not.
Clinic-based testing tends to be more dependable because the sample collection is handled by trained staff, and hospital or public health labs face more oversight and quality control. If you use an at-home kit and get a positive result, you’ll still need to see a provider for a confirmatory test and treatment. If you get a negative result but have symptoms or a known exposure, it’s worth getting retested at a clinic.
Who Should Get Tested
Because syphilis so often produces no symptoms, testing is the only reliable way to catch it. You should consider getting screened if you’re sexually active and any of the following apply: you have a new partner, you’ve had unprotected sex, you or a partner have had other STIs, or you’re a man who has sex with men. Pregnant individuals are routinely screened because syphilis can pass to a baby during pregnancy with devastating consequences.
Syphilis rates have been rising sharply in recent years across the United States, affecting people of all ages and backgrounds. Routine screening is increasingly recommended as part of standard sexual health care, even for people who feel perfectly healthy. A single blood draw can catch an infection that might otherwise silently progress for years.