This page is general health information, not medical advice. It cannot tell you whether you have an infection. A clinician can, and the testing options on this site are a good place to start.

Syphilis is a bacterial infection that is treatable and curable. It is also easy to miss, because its early signs can be painless, brief or mistaken for something else. That is why testing, not guesswork, is how people find out where they stand.

This guide is for anyone in Boston who wants a clear, calm explanation. It covers what syphilis is, how the stages unfold, what syphilis symptoms and a syphilis rash can look like in general terms, how the blood tests work, and what syphilis treatment involves. It also covers where Boston testing is free or low cost.

Nothing here can tell you whether you have syphilis. Only a clinician and a test can do that.

What syphilis is, in plain terms

Syphilis is caused by a spiral-shaped bacterium called Treponema pallidum. The CDC describes it as an infection passed mainly through direct contact with a syphilis sore during vaginal, anal or oral sex. It can also pass from a pregnant person to a baby during pregnancy.

Anyone of any gender or orientation can get syphilis. The bacterium does not care about identity. What matters medically is exposure, and the CDC's guidance is built around that.

The sores can sit inside the mouth, vagina or rectum, or on skin that a condom does not cover. Many people never see or feel them. This is one reason the CDC and clinicians talk about testing rather than waiting for something noticeable.

The stages of syphilis

The CDC STI Treatment Guidelines (2021) describe syphilis in stages. The stages are a way for clinicians to decide how to test, treat and follow up. People do not always move through them in a tidy order, and some stages pass with no notice at all.

Primary syphilis

The first stage usually brings a sore called a chancre where the bacterium entered the body. The CDC says it is typically firm, round and painless. Because it does not hurt, and because it can be inside the body, it is easy to overlook.

The CDC notes the sore heals by itself, usually within a few weeks. Healing does not mean the infection is gone. Without treatment from a clinician, the infection can continue.

Secondary syphilis

The second stage is where many people first notice syphilis symptoms. The best known sign is a syphilis rash. The CDC describes it as often showing up on the trunk, and on the palms of the hands and soles of the feet. It can be rough, reddish-brown or faint, and the CDC says it usually does not itch.

Because it can look like many other skin conditions, a rash alone cannot say what is going on. A clinician can look at it and order a blood test.

Other secondary-stage signs the CDC lists include:

Fever and tiredness
Sore throat
Swollen lymph glands
Patchy hair loss
Headaches and muscle aches
Weight loss
Mucous membrane changes in the mouth or genitals

The CDC says these signs also clear up without treatment. That can feel like recovery, but the infection can remain.

Latent syphilis

The CDC describes latent syphilis as a stage with no signs or symptoms, where the infection is found only by a blood test. Clinicians divide it into early latent and late latent, or latent of unknown duration, because that affects the treatment plan.

This stage is a main reason screening exists. A person can feel entirely well and still have a reactive blood test.

Tertiary syphilis

The CDC says that without treatment, a small share of people go on to tertiary syphilis, years or even decades after the first infection. It can affect the heart, blood vessels, brain and other organs. This is uncommon, and it is a main reason clinicians treat syphilis at any stage.

Syphilis that reaches the nervous system, eyes or ears

The CDC guidelines note that syphilis can involve the nervous system (neurosyphilis), the eyes (ocular syphilis) or the ears (otosyphilis) at any stage. Changes in vision, hearing, balance or thinking are reasons to see a clinician promptly. They are not a reason to panic. Tell the clinician about them so they can decide what testing makes sense.

Why the national rise matters

The CDC's national STI surveillance reports show that syphilis has risen across the United States over the past decade. The increase includes congenital syphilis, which is syphilis passed to a baby during pregnancy. The CDC calls congenital syphilis preventable, since screening and treatment during pregnancy can stop it.

Why does a national trend matter in Boston? A rising national number means more circulating infection overall. It also means clinicians and public health agencies are paying closer attention to who gets screened and how often.

It does not mean any one person is likely to have syphilis. It means testing is a reasonable, ordinary part of sexual health care.

The US Preventive Services Task Force (USPSTF) recommends screening for syphilis in people who are at increased risk, including non-pregnant adolescents and adults. It also recommends screening for all pregnant people. A clinician can talk through what "increased risk" means for you without judgment.

What we know about Boston and Massachusetts

The Boston Public Health Commission is the city's health department. The Massachusetts Department of Public Health sets the state's disease reporting rules.

For this guide, no current published syphilis rate for Boston or Massachusetts could be confirmed. That includes primary and secondary syphilis, congenital syphilis and HIV diagnoses. The Boston Public Health Commission (617-534-5395) and the state health department are the places to ask for current local figures.

There is one local number for other bacterial STIs. CDC county data, republished by Boston 25 News in March 2024, put Suffolk County, which contains Boston, at 807.8 chlamydia cases per 100,000 people in 2021 (6,230 cases), the highest in Massachusetts. The same source put gonorrhea at 298.0 per 100,000 (2,298 cases). These are county figures, not city-only ones, and they are not syphilis numbers.

They do show that STI testing is a routine, well-used part of care in this part of the state.

How syphilis is tested

Syphilis is usually found with a blood test. The CDC explains that no single blood test is used alone. Clinicians use two kinds together, because each answers a different question.

Treponemal tests

These look for antibodies made specifically against the syphilis bacterium. The CDC says they usually remain reactive for life, even after successful treatment. A reactive treponemal test therefore does not tell a clinician by itself whether an infection is new, old or already treated.

Non-treponemal tests

These look for substances the body releases in response to the damage the infection causes. Two common versions are the RPR and the VDRL. They give a number called a titer, such as 1:8 or 1:32, which clinicians can follow over time.

The CDC says this number tends to reflect how active an infection is. It is the main tool for judging whether treatment worked.

Putting the two together

The CDC describes two testing orders. In the traditional sequence, a non-treponemal test comes first and a treponemal test confirms it. In the reverse sequence, a treponemal test comes first and a non-treponemal test follows.

Many labs use the reverse sequence. Either way, the goal is the same. Two tests together give a clinician a more reliable picture than one.

Sometimes the results seem to disagree, for example one test reactive and the other not. This is a known situation in the CDC guidelines, and clinicians have a standard way to sort it out, often with a third test. A mixed result is not an answer in itself, and a clinician can explain what it means for you.

Testing and timing

After an exposure, a blood test may not show syphilis right away. The CDC publishes guidance on timing and retesting. A clinician can tell you whether a repeat test makes sense in your situation. If you are unsure, ask at the clinic.

Syphilis sores can also be tested directly by a clinician in some situations. That depends on the clinic and the finding.

Is syphilis curable?

Yes. The CDC says syphilis is curable with the right antibiotic treatment from a clinician. The preferred medicine is penicillin, given by a clinician, and the CDC guidelines describe it as the treatment with the strongest evidence. It is also the recommended choice in pregnancy.

Which form of penicillin is used, and for how long, depends on the stage. That is a decision for a clinician, and this guide does not give amounts or schedules.

Treatment stops the infection from progressing. The CDC notes it cannot undo damage that has already occurred, which is why earlier treatment matters.

If you are allergic to penicillin, tell the clinician. The CDC guidelines describe options and, in some cases, allergy evaluation or desensitization, particularly during pregnancy. Do not stop or switch treatment on your own.

Safety notes on syphilis treatment

Penicillin has a long safety record, and the CDC guidelines describe it as well established. A few points are worth knowing in advance:

Allergy. Penicillin allergy is the main contraindication. Clinicians ask about it before treating.
The Jarisch-Herxheimer reaction. The CDC describes this as a short-lived reaction, with fever, chills, headache or muscle aches, that can appear within the first day after treatment starts. It is not an allergic reaction. Clinicians can tell you what to expect.
Pregnancy. The CDC recommends penicillin for syphilis in pregnancy, and treatment during pregnancy can protect the baby.
Partners. The CDC guidelines advise that recent sex partners be evaluated, and sometimes treated, even before their own results are in. A clinician or the health department can help with that conversation.

While treatment is underway, the CDC advises avoiding sex until the sores have healed and the clinician says it is fine to resume.

Follow-up blood tests after treatment

Treatment is not the last step. The CDC guidelines call for follow-up blood tests to confirm that the infection is responding. This is where the non-treponemal titer earns its keep.

A clinician repeats the test at set intervals and watches the number. The CDC says a sustained drop in the titer is the expected sign that treatment worked. A titer that does not fall as expected is a prompt for the clinician to look further.

Two things surprise people:

The treponemal test usually stays reactive for life, as noted above. That is normal after treatment and is not a sign of ongoing infection.
A low, stable titer can persist in some people for a long time. The CDC calls this a serofast state, and clinicians have ways to interpret it.

Follow-up schedules vary with the stage and with factors such as pregnancy or HIV. A clinician sets the schedule. Keeping those appointments is the most useful thing you can do after treatment.

Research observations worth knowing

Research suggests several things that can help you think about prevention and care. These are observations from the CDC and USPSTF, not promises.

Screening finds infections without symptoms. The USPSTF's recommendation for screening people at increased risk reflects evidence that treating syphilis early prevents later complications.
Syphilis and HIV can overlap. The CDC notes that syphilis sores can make it easier to acquire or pass HIV. It recommends HIV testing for anyone diagnosed with syphilis, and clinicians often offer both tests together.
Doxycycline after sex. In 2024 the CDC issued guidance on doxycycline taken after sex (doxy-PEP) for certain groups. These are gay, bisexual and other men who have sex with men, and transgender women, who have had a bacterial STI in the past year. Research suggests it lowers the chance of syphilis, chlamydia and gonorrhea in these groups. Whether it is right for you is a decision for you and a prescribing clinician. Fenway Health's page lists doxy-PEP among its services.
Condoms and barriers lower risk but do not remove it. The CDC notes that syphilis sores can occur in places a condom does not cover.
Congenital syphilis is preventable. The CDC says screening and treatment during pregnancy can prevent it.

Where to get tested in Boston

Boston has several places that test for syphilis at no cost or on a sliding scale. Here is what each organization's own page or listing says.

Boston STD Clinic (Boston Medical Center). 725 Albany St., 9th Floor, Suite 9C, Boston, MA 02118. The clinic's page says routine testing for HIV, chlamydia, gonorrhea, syphilis and hepatitis C is free, with cost help for people without insurance. Call 617-414-2803 to make an appointment. The page does not say whether walk-ins are accepted. Hours are listed as Monday, Wednesday and Friday, 9 a.m. to 4 p.m., and Tuesday and Thursday, 9 a.m. to 7 p.m., so confirm by phone.
Fenway Health Sexual Health Clinic. Ansin Building, 1340 Boylston Street, 4th floor, Boston, MA 02215. Fenway's page lists walk-in hours: Tuesday 1 to 7 p.m., Wednesday and Thursday 3 to 7 p.m., and Friday 9 a.m. to 12 p.m. Monday is by appointment, 9 a.m. to 4 p.m. Check-in closes 30 minutes before the end time, and results take 3 to 5 business days. The page says the clinic bills insurance if you have it, and that uninsured patients can be seen free through grant funding. Call 617-267-0159. The page is aimed at gay, bisexual and other men who have sex with men, transgender and gender diverse people, and their partners.
X-Clinic at Codman Square Health Center. 637 Washington St., Dorchester, MA 02124. Codman's page lists walk-in express visits for people without symptoms or a known exposure, on a sliding fee scale, regardless of citizenship status. Its two pages show different hours, so call 617-822-8350 to confirm.
TrueCare@MAC (Multicultural AIDS Coalition). 9 Palmer Street, Roxbury, MA 02119. The Multicultural AIDS Coalition lists free testing with or without an appointment, and Saturday hours. Call 617-442-1622 for current times.
Boston Public Health Commission. 774 Albany St., Boston, MA 02118, 617-534-3976. The CDC's GetTested directory lists free syphilis, HIV, hepatitis C, chlamydia and gonorrhea testing. The directory does not list hours or confirm walk-ins, so call first.
Planned Parenthood League of Massachusetts, Greater Boston Health Center. 1055 Commonwealth Ave, Boston, MA 02215, 617-295-7235. The CDC directory lists a sliding scale and says appointments are required.
DotHouse Health. 1353 Dorchester Avenue, Dorchester, MA 02122, 617-288-3230. The CDC directory lists a sliding scale and English, Portuguese and Spanish.

Clinics list different services, so when you call, ask whether syphilis blood testing is part of the visit. You can also find more options at the CDC's GetTested directory. For a fuller side-by-side look at the city's options and what visits cost, see our guide to STD testing in Boston.

The Mayor's Health Line, 617-534-5050, is a free, confidential, multilingual line for health information and referrals.

Quality indicators when choosing where to test

Because there is no product to buy, "sourcing" here means choosing a trustworthy place to get tested. Some practical signs of quality:

The clinic is a health department, hospital or community health center that you can verify through its own website or the CDC directory.
A licensed clinician reviews results and explains them, rather than only sending a result.
The clinic can treat on site or refer you quickly if a test is reactive.
It can pair syphilis testing with HIV and other STI tests, and explain follow-up.
It is clear about cost before the visit, and about what happens with insurance billing.

Privacy and your rights in Massachusetts

Under M.G.L. c. 111, s. 111, venereal disease cases are reported to local boards of health under state department rules. Under s. 119, those reports and records are not public. They can be shared only on a judicial order or with officials whose duties entitle them.

For younger people, M.G.L. c. 112, s. 12F lets a minor who reasonably believes they are at risk of exposure from sexual activity consent to care to diagnose or treat the disease without a parent's consent. The City of Boston tells people 13 or older that they can get a confidential STI test without parental permission. Records are kept confidential between the minor and the provider, except where the minor's life or limb is seriously endangered.

Questions people often ask

Can syphilis symptoms go away on their own?

The CDC says the sores and rash of the early stages can fade without treatment. The infection can stay in the body even so. Only a clinician and a test can say what is happening.

Does a syphilis rash always look the same?

No. The CDC notes it can be faint or varied, and it may resemble other skin conditions. That is why a clinician's exam and a blood test matter more than appearance.

Is syphilis curable if it has been there a long time?

Antibiotic treatment from a clinician can cure the infection at any stage, according to the CDC. Earlier treatment prevents more damage. Damage that already happened may not be reversible.

Can I get syphilis again after treatment?

The CDC notes that treatment does not protect against future infection. Testing is again an option if there is a new exposure, and a clinician can help you decide when.

What should I tell the clinician?

Share whatever feels relevant: any new sores, rashes or other changes, pregnancy, medicine allergies and the timing of any possible exposure. Clinics see this every day, and none of it is judged.

The takeaway

Syphilis is a well-understood infection with a reliable cure when a clinician treats it. It can be quiet, so a blood test is how people learn more. Two kinds of blood tests work together, and follow-up tests show whether treatment worked.

Boston has free and low-cost options. If you would like to talk through whether testing makes sense for you, a clinic call is a good first step.

Syphilis in Boston: Symptoms, Testing and Treatment