Syphilis in the Philippines: symptoms, testing, and treatment

Syphilis has been making a quiet but significant comeback in the Philippines. As a medical technologist, I see the numbers firsthand in the laboratory. More reactive RPR results, more confirmatory TPHA tests ordered, and more patients learning about a diagnosis they never expected. This guide breaks down everything you need to know about syphilis in the Philippines — what it is, how it progresses through stages, how we diagnose it in the lab, how it is treated, and why it matters for HIV prevention.

If you want a broader overview of STI testing, see our complete STI testing guide.

Syphilis is rising in the Philippines

Syphilis is not a disease of the past. Data from the Department of Health (DOH) shows a sustained increase in reported syphilis cases across the Philippines over the past decade. The DOH HIV/AIDS and ART Registry of the Philippines (HARP) consistently flags syphilis as the most commonly reported STI at social hygiene clinics nationwide. Surveillance reports indicate that the majority of new cases are among sexually active adults aged 15 to 34, with higher concentrations in urban centers like Metro Manila, Cebu, and Davao. Men who have sex with men are disproportionately affected, as outlined in our sexual health guide for MSM.

The rise in syphilis mirrors global trends observed by the World Health Organization (WHO), which estimated 7.1 million new syphilis infections worldwide in 2020. In the Philippines, expanded testing at social hygiene clinics has helped identify more cases, but public health experts believe that many infections still go undiagnosed because syphilis symptoms can be subtle or absent entirely.

Understanding syphilis is not just a medical exercise. It is a practical matter of public health, particularly because of the strong connection between syphilis and HIV transmission.

What causes syphilis

Syphilis is caused by Treponema pallidum, a spiral-shaped bacterium known as a spirochete. Under a darkfield microscope, the organism has a distinctive corkscrew appearance and characteristic motility. T. pallidum is a fragile organism that cannot survive long outside the human body, which is why it requires direct contact for transmission. It cannot be spread through casual contact, sharing utensils, toilet seats, or swimming pools.

What makes T. pallidum particularly challenging is its ability to evade the immune system and establish long-term infection. Without treatment, the bacterium can persist in the body for years or even decades, progressing through distinct clinical stages.

How syphilis is transmitted

Sexual contact

Syphilis is primarily transmitted through direct contact with a syphilis sore (chancre) or rash during vaginal, anal, or oral sex. The sores are most commonly found on the genitals, anus, rectum, or lips and mouth. Because primary chancres are painless, many people do not realize they have an infectious sore and unknowingly transmit the infection to their partners.

Mother-to-child transmission

Syphilis can also be passed from a pregnant mother to her unborn child, a condition known as congenital syphilis. This can happen at any stage of pregnancy and can lead to miscarriage, stillbirth, premature birth, or serious health problems in the newborn including bone deformities, anemia, and neurological damage. The DOH recommends syphilis screening for all pregnant women as part of routine prenatal care, and treating infected mothers promptly to prevent transmission.

The four stages of syphilis

One of the most important things to understand about syphilis is that it progresses through distinct stages, each with different symptoms and implications. Without treatment, the infection advances from one stage to the next over months or years.

Primary syphilis

Primary syphilis begins with the appearance of a chancre, a firm, round, painless sore at the site where the bacterium entered the body. This is usually on the genitals, anus, or mouth. The chancre typically appears 10 to 90 days after exposure, with an average of about 21 days. Because the sore is painless and may be located in areas that are difficult to see (such as inside the vagina, on the cervix, or in the rectum), many people never notice it.

The chancre heals on its own within three to six weeks, which leads many people to believe the infection has resolved. It has not. Without treatment, the bacteria have already spread through the bloodstream.

Secondary syphilis

If primary syphilis is not treated, the disease progresses to the secondary stage weeks to months later. Secondary syphilis is characterized by a skin rash that often appears on the palms of the hands and soles of the feet, though it can occur anywhere on the body. The rash is typically not itchy. Other symptoms may include mucous patches in the mouth, hair loss, swollen lymph nodes, fever, fatigue, and muscle aches.

Secondary syphilis symptoms will also resolve on their own without treatment, but again, the infection remains active in the body.

Latent syphilis

After the secondary stage, syphilis enters a latent (hidden) period where there are no visible signs or symptoms. The infection is divided into early latent syphilis (within the first year of infection) and late latent syphilis (more than one year after infection). During the early latent stage, the infection can still be transmitted to sexual partners. During late latent syphilis, transmission is less likely but the bacterium continues to cause internal damage.

Latent syphilis can last for years or even decades. The only way to detect it during this stage is through blood testing.

Tertiary syphilis

If syphilis remains untreated for 10 to 30 years, it can progress to tertiary syphilis, the most destructive stage. Tertiary syphilis can cause gummas (soft, tumor-like growths), cardiovascular syphilis (damage to the heart and blood vessels), and neurosyphilis (damage to the brain and nervous system). Neurosyphilis can also occur at any stage of infection.

Fortunately, tertiary syphilis is rare today because most cases are detected and treated before they reach this point. However, the risk underscores why early testing and treatment are so important.

How syphilis is diagnosed

As a medical technologist, syphilis testing is one of the most common screening procedures I perform in the laboratory. The diagnosis of syphilis relies on blood tests that detect antibodies produced by the body in response to the T. pallidum infection. There are two main categories of syphilis tests, and understanding how they work together is essential.

Non-treponemal tests (screening)

The most common screening tests for syphilis are the RPR (Rapid Plasma Reagin) and VDRL (Venereal Disease Research Laboratory) tests. These tests detect non-specific antibodies called reagin that the body produces in response to tissue damage caused by T. pallidum. In the lab, we mix a sample of the patient's serum with a cardiolipin-lecithin-cholesterol antigen and look for visible clumping (flocculation).

Because these tests detect non-specific antibodies, they can occasionally produce false-positive results. Conditions such as pregnancy, autoimmune diseases like lupus, certain viral infections, and even old age can trigger a reactive RPR or VDRL without an actual syphilis infection. This is why a reactive screening test always requires confirmation.

One important advantage of non-treponemal tests is that they produce a titer (a numerical measurement of antibody levels). The titer is essential for monitoring treatment response. A declining titer after treatment indicates successful therapy, while a rising titer may suggest reinfection or treatment failure.

Treponemal tests (confirmatory)

When a screening test comes back reactive, the next step is a treponemal confirmatory test. The two most commonly used confirmatory tests in the Philippines are the TPHA (Treponema Pallidum Hemagglutination Assay) and the FTA-ABS (Fluorescent Treponemal Antibody Absorption) test. These tests detect antibodies that are specifically directed against T. pallidum proteins, making them highly accurate.

An important thing to know about treponemal tests is that once they become reactive, they typically remain reactive for the rest of a person's life, even after successful treatment. This means a positive TPHA does not necessarily indicate an active infection. It tells us the person has been exposed to syphilis at some point. The RPR or VDRL titer is then used to determine whether the infection is currently active.

Rapid syphilis tests

Rapid syphilis tests are immunochromatographic assays that can provide results in 15 to 20 minutes using a finger-prick blood sample. These point-of-care tests are treponemal tests, meaning they detect T. pallidum-specific antibodies. They are increasingly used in outreach settings, community-based testing events, and social hygiene clinics where fast results enable same-day treatment.

While rapid tests are convenient, a reactive rapid test should still ideally be followed by a quantitative RPR or VDRL to establish a baseline titer for treatment monitoring.

What reactive and non-reactive mean

When you receive your syphilis test results, they will be reported as either reactive or non-reactive. A non-reactive result means no antibodies were detected and you are most likely not infected (keeping in mind the window period of a few weeks after exposure). A reactive result means antibodies were detected, and further testing or evaluation is needed to determine whether you have an active infection, a past treated infection, or a false positive.

The syphilis testing pathway

Treatment for syphilis

The good news about syphilis is that it is completely curable, especially when caught early. Treatment has remained remarkably consistent for decades.

Penicillin: the gold standard

Benzathine penicillin G (also known as Bicillin) is the first-line treatment for syphilis and has been the drug of choice since the 1940s. It is administered as an intramuscular injection, typically in the gluteal muscle. Penicillin works by inhibiting the cell wall synthesis of T. pallidum, effectively killing the bacterium.

Treatment by stage

The treatment regimen depends on the stage of syphilis:

• Primary, secondary, or early latent syphilis — a single intramuscular injection of Benzathine penicillin G (2.4 million units)
• Late latent syphilis or syphilis of unknown duration — three injections of Benzathine penicillin G (2.4 million units each), given once per week for three consecutive weeks
• Neurosyphilis — intravenous aqueous crystalline penicillin G for 10 to 14 days, administered in a hospital setting

After treatment, patients are followed up with repeat RPR or VDRL testing at 3, 6, and 12 months. A fourfold decline in the RPR titer (for example, from 1:32 to 1:8) indicates successful treatment.

Penicillin allergy

For patients with a documented penicillin allergy, alternative treatments include doxycycline (100 mg orally twice daily for 14 days for early syphilis, or 28 days for late latent syphilis). However, penicillin remains so critical for syphilis treatment that allergists often recommend penicillin desensitization for allergic patients, particularly pregnant women, for whom doxycycline is contraindicated.

Syphilis and HIV co-infection

The relationship between syphilis and HIV is bidirectional and clinically significant. Syphilis sores and the mucosal inflammation they cause compromise the body's natural barriers, making it easier for HIV to enter the bloodstream during sexual contact. Conversely, people living with HIV who acquire syphilis may experience faster disease progression, atypical symptoms, and a higher risk of neurosyphilis even in early stages of the infection.

For people living with HIV, syphilis treatment follows the same penicillin regimen, but closer monitoring is recommended. RPR titers may take longer to decline, and some clinicians opt for more frequent follow-up testing at monthly intervals during the first six months.

The DOH and the WHO both recommend concurrent testing for syphilis and HIV as standard practice. At social hygiene clinics in the Philippines, both tests are routinely offered together during STI screening visits. If you are getting tested for one, ask for the other as well.

For more about HIV testing in the Philippines, read our HIV testing guide.

Where to get tested in the Philippines

The most accessible option for free syphilis testing is through the network of Social Hygiene Clinics (SHCs) operated by local government units across the Philippines. Many of these same facilities also offer free HIV testing. There are over 100 SHCs nationwide, and they provide free STI screening including syphilis RPR testing, confirmatory tests, and treatment.

Here is what to expect:

• Cost — testing and treatment at SHCs are free of charge
• Walk-in — most SHCs accept walk-in patients during clinic hours (typically weekday mornings)
• Confidential — your results are kept confidential under the Philippine HIV and AIDS Policy Act (R.A. 11166) and the Responsible Parenthood and Reproductive Health Act (R.A. 10354)
• Results — RPR screening results are usually available within the same day; confirmatory results may take a few days

You can also get tested at private laboratories and hospitals, though these will involve out-of-pocket costs. A basic RPR test at a private lab typically costs between 200 to 500 pesos, while a TPHA confirmatory test may cost 500 to 1,500 pesos.

Use our facility directory to find a social hygiene clinic or HIV testing center near you, or connect with a community-based screener for free, confidential testing.

Prevention

Preventing syphilis involves the same practical strategies used for other sexually transmitted infections:

• Use condoms consistently and correctly — condoms significantly reduce the risk of syphilis transmission, though they do not eliminate it entirely since sores can occur in areas not covered by a condom
• Limit sexual partners — reducing the number of sexual partners lowers your overall exposure risk
• Get tested regularly — if you are sexually active with multiple partners, screen for syphilis (and other STIs) every 6 to 12 months
• Communicate with partners — discuss STI testing and status openly with sexual partners
• Seek treatment promptly — if you or a partner tests reactive, complete the full treatment course and avoid sexual contact until cleared by your healthcare provider
• Prenatal screening — all pregnant women should be tested for syphilis early in pregnancy to prevent congenital syphilis
• Consider doxy-PEP — emerging evidence supports post-exposure prophylaxis with doxycycline (doxy-PEP) for reducing syphilis risk; learn more in our doxy-PEP guide

Frequently asked questions

Can syphilis be cured? Yes. Syphilis is a bacterial infection and is completely curable with appropriate antibiotic treatment, most commonly Benzathine penicillin G injections. Early-stage syphilis can be cured with a single injection.

How soon after exposure should I get tested? Syphilis antibodies typically become detectable within 2 to 4 weeks after exposure, though it can take up to 12 weeks in some cases. If you suspect recent exposure, get tested at 3 to 4 weeks and consider a follow-up test at 12 weeks for certainty.

Can I get syphilis from kissing? Syphilis is transmitted through direct contact with a syphilis sore. If a sore is present on the lips or inside the mouth, transmission through kissing is theoretically possible, but this is uncommon compared to sexual transmission.

Will syphilis go away on its own? No. While the symptoms of primary and secondary syphilis resolve on their own, the infection does not. Without treatment, syphilis will progress through its stages and can eventually cause serious organ damage.

Can I get syphilis more than once? Yes. Having syphilis once does not make you immune. You can be reinfected if exposed again after treatment. This is why regular testing is important for sexually active individuals.

What does a positive TPHA mean if I was already treated? A reactive TPHA after treatment is expected and does not mean you are still infected. Treponemal tests remain reactive for life in most cases. Your doctor will use your RPR titer to determine whether you have an active infection or a successfully treated past infection.

Is syphilis testing confidential in the Philippines? Yes. Under R.A. 11166 (Philippine HIV and AIDS Policy Act) and related health privacy regulations, your STI test results are confidential. Social hygiene clinics follow strict confidentiality protocols.

Do I need to test for HIV if I have syphilis? Strongly recommended. The DOH and WHO recommend concurrent HIV and syphilis testing because having one infection significantly increases the risk of acquiring the other.

Sources and references

1. CDC. "About STIs." https://www.cdc.gov/sti/about/index.html
2. WHO. "Sexually Transmitted Infections (STIs) Fact Sheet." https://www.who.int/news-room/fact-sheets/detail/sexually-transmitted-infections-(stis)
3. CDC. "About HIV." https://www.cdc.gov/hiv/about/index.html
4. Department of Health, Philippines. HIV/AIDS and ART Registry of the Philippines (HARP) reports, 2020-2025. https://doh.gov.ph/
5. World Health Organization. Global health sector strategies on sexually transmitted infections, 2022-2030. Geneva: WHO, 2022.
6. Centers for Disease Control and Prevention. Syphilis: CDC detailed fact sheet. Updated 2024.
7. Workowski KA, Bachmann LH, Chan PA, et al. Sexually Transmitted Infections Treatment Guidelines, 2021. MMWR Recomm Rep 2021;70(No. RR-4):1-187.
8. Philippine HIV and AIDS Policy Act, Republic Act No. 11166 (2018).
9. Ghanem KG. Management of adult syphilis: key questions to inform the 2021 CDC STI treatment guidelines. Clin Infect Dis. 2020;71(Suppl 1):S26-S36.
10. Peeling RW, Mabey D, Kamb ML, Chen XS, Radolf JD, Benzaken AS. Syphilis. Nat Rev Dis Primers. 2017;3:17073.