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 spreads through sexual contact and can also pass from a pregnant person to a baby. It is one of the oldest known infections. It is also one of the few that doctors can still reliably cure.

This guide covers what the bacterium does in the body, how syphilis symptoms change across stages, how blood tests work, and what treatment looks like. It also covers what the numbers say for Los Angeles and where to get tested.

Anyone of any gender or orientation can get syphilis. Testing is a routine health step, not a judgment.

The short version

Syphilis is caused by a bacterium called Treponema pallidum.
It moves through stages. Early signs can be painless and easy to miss, and they can fade without treatment while the infection stays.
Blood tests are the main way clinicians find it. Two kinds are usually used together.
Is syphilis curable? Yes. The CDC says penicillin prescribed by a clinician cures it at every stage. Follow-up blood tests then confirm the treatment worked.
Los Angeles County has several free sexual health clinics that test for it.

What causes syphilis: the organism

In a deep dive on an ingredient, this is where we would talk about composition. For an infection, the equivalent is the organism itself.

Treponema pallidum is a spirochete, a thin, corkscrew-shaped bacterium. The CDC describes it as spreading through direct contact with a syphilis sore, usually during vaginal, anal or oral sex. A pregnant person can also pass it to a baby during pregnancy.

Research suggests this bacterium is unusually hard to study. Laboratories cannot grow it routinely in a dish the way they grow many other bacteria. That is one reason diagnosis relies on blood tests that look for the body's response, rather than on culturing the organism.

Its structure also helps it persist. Research suggests the bacterium has few proteins on its outer surface, which may make it harder for the immune system to spot. That helps explain how an untreated infection can linger for years.

One reassuring finding: the CDC's treatment guidelines note that no penicillin resistance has been documented in T. pallidum. That is a main reason penicillin remains the standard treatment decades after it was first used.

The stages of syphilis

The CDC describes syphilis in stages. The stages can overlap, and a person may not notice any of them. Only a clinician and a test can say whether an infection is present or which stage it might be.

Primary syphilis

The CDC says the first sign is usually a sore called a chancre. It appears where the bacterium entered the body, such as the genitals, anus or mouth. It is typically firm, round and painless.

According to the CDC, the sore usually appears about three weeks after exposure, though the range is roughly 10 to 90 days. It heals by itself in a few weeks. Because it does not hurt and can sit inside the vagina, rectum or mouth, many people never see it.

Secondary syphilis

The CDC says the next stage can bring a skin rash and other signs. This is the stage most people mean when they search for the syphilis rash.

The CDC describes the syphilis rash as often rough, reddish-brown or pink spots. It can appear on the palms of the hands and soles of the feet, or on the trunk and elsewhere. It usually does not itch. It can be faint enough that it goes unnoticed.

Other secondary syphilis symptoms listed by the CDC include:

Fever and tiredness
Sore throat
Swollen lymph glands
Patchy hair loss
Headaches and muscle aches
Weight loss
Wart-like patches in warm, moist areas, and sores in the mouth or genital area

Many conditions cause rashes, including allergies, viral illnesses and skin conditions. A rash alone cannot point to syphilis. A clinician can look at the skin and order a blood test to find out.

Like the first sore, these signs can clear without treatment. The CDC notes that fading signs do not mean the infection has gone.

Latent syphilis

The CDC describes a hidden stage with no signs at all. The infection is still present and can only be found with a blood test. This stage can last for years.

Tertiary syphilis

The CDC says that in a minority of people with untreated infection, serious problems can develop years to decades later. These can affect the heart, blood vessels, brain and nerves. Treatment can stop further damage. It may not reverse damage that has already happened, which is a strong reason to test early.

Infection of the eyes, ears and nervous system

The CDC notes that syphilis can reach the eyes (ocular syphilis), the ears (otosyphilis) or the nervous system (neurosyphilis) at any stage. Vision changes, hearing changes, severe headache or confusion are reasons to seek care promptly. A clinician can decide which tests and treatment are appropriate.

Why the national rise matters

The CDC reports that syphilis cases in the United States have risen for many years, including cases in babies born with the infection. Congenital syphilis is the form passed during pregnancy. It can cause serious harm to a baby, but it is largely preventable when a pregnant person is tested and treated in time.

The rise is a reason for routine screening. It does not mean any one person is at fault. Screening finds infections that have no signs, which is how most onward spread happens.

The U.S. Preventive Services Task Force (USPSTF) recommends syphilis screening for all pregnant people. It also recommends screening for adolescents and adults who are at increased risk. A clinician can talk through what that means for any individual.

Syphilis in Los Angeles and California: the numbers

These figures come from public health agencies. They are provisional in some cases and use different boundaries, so read them as a snapshot.

Measure (2024)	Los Angeles County*	California
Early syphilis (infectious stages)	36 per 100,000 (3,344 cases)	24.4 per 100,000 (9,549 cases)
Congenital syphilis	102 cases; 120 per 100,000 live births	438 cases; 109.2 per 100,000 live births

*The Los Angeles County Department of Public Health 2024 STI Surveillance Snapshot excludes Long Beach and Pasadena, which have their own health departments. The county's early syphilis figure is provisional. State figures are from the California Department of Public Health (CDPH) report, Sexually Transmitted Infections in California 2024.

CDPH also reports 68.2 cases per 100,000 for all acquired syphilis statewide in 2024 (26,732 cases). That total includes later stages as well as early infections.

The county's early syphilis rate sits above the statewide rate. The county's congenital syphilis rate is also above the state's. Both are reasons Los Angeles health agencies emphasize testing during pregnancy.

What California law says about prenatal testing

California Health and Safety Code section 120685, as amended by SB 306 (effective January 1, 2022), requires licensed professionals who provide prenatal care or attend a delivery to screen for syphilis according to CDPH guidelines. CDPH's fact sheet describes three screens:

At confirmation of pregnancy or the first prenatal visit
In the early third trimester, about 28 weeks
At delivery

The same CDPH fact sheet says emergency departments and hospital-affiliated urgent care should screen pregnant people before discharge if no result exists for the current pregnancy.

How syphilis is tested: the two kinds of blood test

The CDC's 2021 STI Treatment Guidelines describe a two-part approach. Most syphilis testing uses blood drawn from a vein. A clinician may also test fluid from a sore under a microscope when one is present.

Non-treponemal tests

These tests, such as the RPR and VDRL, measure antibodies the body makes in response to damage the infection causes. They give a number called a titer, written as a ratio. The CDC says the titer is useful for tracking treatment. A falling titer after treatment suggests the treatment is working.

Treponemal tests

These tests look for antibodies aimed at the bacterium itself. The CDC says they usually stay positive for life after an infection, even after successful treatment. That is why they confirm that someone has been exposed at some point, but cannot show when or whether treatment worked.

Why two tests are used together

Each test type can produce misleading results alone. The CDC guidelines describe two sequences:

The traditional sequence starts with a non-treponemal test and confirms a reactive result with a treponemal test.
The reverse sequence starts with a treponemal test and checks a reactive result with a non-treponemal test.

Which sequence a laboratory uses varies. The results can be hard to read without context, and a clinician puts them together with symptoms, exposure history and any past testing.

Timing and the window period

The CDC does not publish a single fixed window period for syphilis tests. Antibodies can take time to build after exposure. A test taken very soon after exposure may be too early to show an infection.

If a recent exposure is a concern, a clinician can say when testing is most useful and whether to repeat it. The CDC also recommends that anyone diagnosed with syphilis be tested for HIV, since the infections can occur together.

Treatment: is syphilis curable?

Yes. Syphilis is a bacterial infection, and the CDC states it can be cured with the right antibiotic prescribed by a clinician. Penicillin is the preferred syphilis treatment at every stage. The form, the number of doses and the length of treatment depend on the stage and other factors, and a clinician decides them.

Treatment is a prescription matter. This guide does not list doses or schedules, because those depend on the stage of infection, pregnancy, allergies and other conditions.

What treatment does and does not do

The CDC says treatment kills the bacterium and stops the infection from progressing. It may not repair damage already done in later stages. Early treatment gives the best chance of avoiding lasting problems.

Safety profile and contraindications

Penicillin has been used for decades. Research and clinical experience suggest it is well tolerated by most people, but some points deserve a conversation with a clinician:

Penicillin allergy. Some people report a penicillin allergy. Clinicians can often evaluate whether it is real. The CDC says that for pregnant people, penicillin is the only recommended treatment, so a person with a true allergy is generally treated after a process called desensitization under medical care.
Pregnancy. The CDC guidelines recommend penicillin during pregnancy because other antibiotics have not been shown to reliably protect the baby.
Jarisch-Herxheimer reaction. The CDC describes a short-term reaction that can occur within the first day after treatment. It can include fever, chills, headache and muscle aches. It is a response to the bacteria dying, not a sign the treatment failed. A clinician can explain what to expect and when to call.
Other conditions. People with HIV, or with signs affecting the eyes, ears or nervous system, may need different evaluation or treatment. A clinician decides what applies.

Do not use leftover antibiotics or antibiotics from a friend. They may not treat syphilis, and they can hide signs while the infection continues.

Follow-up blood tests

Treatment is not the end of care. The CDC guidelines recommend follow-up blood tests to confirm the infection is responding. For early syphilis, clinical and blood test evaluation is recommended at about 6 and 12 months after treatment. The goal is a meaningful drop in the non-treponemal titer, which the CDC describes as a fourfold decrease within 6 to 12 months for primary and secondary syphilis.

Some people keep a low, stable titer after successful treatment. The CDC calls this a serofast state. A clinician can tell the difference between that and a reinfection or treatment problem.

The CDC also notes that having syphilis once does not protect against getting it again. Retesting after later exposures is part of routine care. Partners may also need testing, and the clinic can explain how that works.

Prevention, including doxy-PEP

Condoms and other barrier methods lower the chance of syphilis when they cover the area with a sore. Sores can sit in areas a condom does not cover, so protection is not complete.

In 2024 the CDC issued guidance on doxycycline post-exposure prophylaxis, often called doxy-PEP. The CDC recommends clinicians discuss it with gay, bisexual and other men who have sex with men, and transgender women, who have had a bacterial STI in the past 12 months. Research reviewed by the CDC suggests it lowers the chance of syphilis, chlamydia and gonorrhea after sex. It is a prescription from a clinician, and the CDC guidance covers who it fits and what to monitor.

Los Angeles County Department of Public Health Sexual Health Clinics list DoxyPEP among their services at no patient charge, along with PrEP and PEP.

Where to get tested in Los Angeles

Several clinics test for syphilis at no cost or low cost. For the full local list with details, see the Los Angeles clinic list. Here is a summary.

Los Angeles County DPH Sexual Health Clinics

All DPH sexual health appointments go through one scheduling line, (213) 449-7009. The county says its clinics charge patients no fees, bill insurance when someone has it, and apply no copay or coinsurance. Appointments are preferred, with limited walk-ins. Telehealth visits are offered by phone booking.

Central Health Center, 241 Figueroa St., Los Angeles, CA 90012. Full-service, including STD and HIV testing, PrEP, PEP, DoxyPEP and treatment. DPH lists it as closed on Mondays.
MLK Jr. Center for Public Health, 11833 S. Wilmington Ave, Los Angeles, CA 90059. Full-service, with the same range of services.
Pacoima Health Center, 13300 Van Nuys Blvd, Pacoima, CA 91331. This site offers screening only. DPH tells people with symptoms or a possible exposure to book at another DPH clinic for evaluation and treatment.

DPH says results come through the LA Health Portal in 2 to 10 business days. It also says its clinics are open to everyone regardless of citizenship, and that it will not report immigration status.

Community clinics

Los Angeles LGBT Center, McDonald/Wright Building, 1625 N. Schrader Blvd., Los Angeles, CA 90028. The county lists it as accepting walk-ins and same-day appointments Monday to Friday, 10am to 7pm, at (323) 993-2997. The Center's page does not state a price for STI testing, so ask the clinic about cost.
AHF Wellness Center, Western, 1811 N. Western Ave., Los Angeles, CA 90027. AHF says on its FAQ page that it tests for gonorrhea, chlamydia, syphilis and HIV, with no appointment needed. The county lists hours Tuesday to Friday 10am to 8pm and Saturday 9:30am to 5:30pm. Phone: 1 (855) 783-2434. AHF suggests calling ahead about wait times.
APLA Health, Gleicher/Chen Health Center Annex, 3741 S. La Brea Ave., Los Angeles, CA 90016. APLA says its Out Here locations offer free or low-cost sexual health services. Its pages direct patients to book an appointment, so call (213) 201-5000.
Watts Health Center, 10300 Compton Ave., Los Angeles, CA 90002. The county lists it for STD screening and treatment, daily 9am to 2pm. Phone: 1 (323) 564-4331. The county listing does not give cost or walk-in details, so check with the clinic.

For teens and young adults

Children's Hospital Los Angeles offers STD services for ages 12 to 24 at 3250 Wilshire Blvd., 3rd Floor, Los Angeles, CA 90010, phone 1 (323) 361-7550. The county lists weekday hours of 9am to 12pm and 1pm to 4pm. Check with the hospital about cost.

Under California Family Code section 6926, a minor 12 or older can consent to STI testing and treatment. The Guttmacher Institute lists no parental notification requirement for California, and the statute says parents are not liable for payment. LA County DPH clinics tell patients 12 and older they can be tested and treated without their parents knowing.

Other ways to find a clinic

The CDC runs a national locator at gettested.cdc.gov. LA County's STD hotline for finding free testing is 800-758-0880. The county's HIV hotline is 800-367-AIDS (2437).

Hours and policies change. Call the clinic or check the health department's Sexual Health Clinics page before going.

How clinics report syphilis

Under California regulations (17 CCR 2500), health care providers report syphilis, gonorrhea and HIV to the local health officer. Laboratories report syphilis results to the local health department under 17 CCR 2505. This reporting feeds the surveillance numbers used in this guide and helps health departments offer partner services. A clinic can explain how this works for any visit.

Quality indicators when choosing where to test

Sourcing matters for care as much as for any product. These signs suggest a testing site is dependable:

It is run by a health department, a hospital or a licensed community health center.
Blood is drawn by trained staff and analyzed by a licensed laboratory.
A clinician reviews results and explains what they mean, including both test types.
Treatment and follow-up are available on site or through a clear referral.
The clinic explains cost, confidentiality and how results are delivered.

Questions people ask

Can syphilis go away on its own?

The CDC says signs of syphilis can disappear without treatment, but the infection stays in the body. Treatment from a clinician is what clears it.

Does syphilis always cause a rash?

No. The CDC says some people never notice any signs, and the secondary rash can be faint. Blood testing is how most infections are found.

Is syphilis treatment safe in pregnancy?

The CDC recommends penicillin during pregnancy. A clinician can talk through allergies and monitoring.

Can I get tested if I do not have a regular doctor?

Yes. The clinics above accept people without a regular provider. DPH clinics are open regardless of citizenship.

How is chlamydia different?

Chlamydia is also a curable bacterial infection, but it is tested with a swab or urine sample rather than blood. Read more in our guide to chlamydia symptoms, testing and treatment in Los Angeles.

Next steps

Syphilis is common enough in Los Angeles that testing is a routine part of sexual health care, and it is curable. If you want to get tested, our guide to STD testing in Los Angeles compares options and explains what to expect at a visit. A clinician can also answer questions about symptoms, timing and treatment.

Syphilis in Los Angeles: Symptoms, Testing and Treatment