Syphilis: Symptoms, Stages & Treatment Options

Syphilis is a bacterial sexually transmitted infection (STI) caused by Treponema pallidum. It spreads primarily through sexual contact and progresses through distinct stages if left untreated. The most common way to become infected is through unprotected vaginal, anal, or oral sex. Syphilis is completely curable with antibiotic treatment, particularly when detected early. During the first year after infection (early syphilis), the disease can be transmitted sexually. In later stages, while sexual transmission becomes less likely, the bacteria can still spread through blood, including from mother to child during pregnancy.

What Are the Symptoms of Syphilis?

Syphilis symptoms vary depending on the stage of infection. The first sign is typically a painless sore (chancre) at the site where the bacteria entered the body, appearing about three weeks after exposure. If untreated, the infection progresses to cause skin rashes, fever, and eventually can damage internal organs. Some people have no noticeable symptoms, which is why testing is essential.

Syphilis is sometimes called "the great imitator" because its symptoms can mimic many other conditions, making diagnosis challenging without proper testing. The symptoms appear in distinct stages, and the disease can remain dormant (latent) between active phases. Understanding these stages helps individuals recognize when to seek testing and treatment.

It's important to note that some people experience no symptoms at all, particularly in the early stages. This "silent" presentation means that many individuals unknowingly carry and transmit the infection to sexual partners. This is one of the main reasons why regular STI testing is recommended for sexually active individuals, especially those with new or multiple partners.

Primary Syphilis (First Stage)

The hallmark of primary syphilis is the appearance of a chancre - a small, round, painless sore that develops at the site where the bacteria entered the body. This sore typically appears 10 days to 3 months after exposure, with most people noticing it around three weeks after infection. The chancre is usually between 1-2 centimeters in size and can easily go unnoticed, especially if located inside the vagina, rectum, or mouth.

Common locations for the primary sore include the genitals (penis, vulva, vagina), the area around the anus, and the mouth or lips. The lymph nodes in the groin area often become swollen if the sore is located on the genitals. Crucially, the chancre heals on its own within 6-8 weeks without any treatment - but this does not mean the infection is gone. Without antibiotic treatment, the bacteria remain in the body and the disease progresses to the next stage.

Secondary Syphilis (Second Stage)

If primary syphilis is not treated, the infection spreads through the bloodstream within 4-10 weeks after the initial sore appears, causing secondary syphilis. This stage is characterized by systemic symptoms affecting multiple parts of the body. The most distinctive feature is a skin rash that can appear anywhere on the body but characteristically affects the palms of the hands and soles of the feet with reddish-brown spots.

The rash may look different in various individuals - it can be rough, bumpy, smooth, or scaly - and may resemble other skin conditions. Some people develop wart-like growths in warm, moist areas like the genitals or armpits. Mucous membrane lesions (small sores) may appear in the mouth, vagina, or rectum. These symptoms may come and go over the first 1-2 years of infection if left untreated.

Other common symptoms during secondary syphilis include:

• Fever: Usually low-grade, but can be persistent
• Fatigue: General feeling of tiredness and malaise
• Headache: Can be mild to moderate in intensity
• Swollen lymph nodes: Throughout the body, not just in the groin
• Hair loss: Patchy hair loss on the scalp, eyebrows, or beard
• Weight loss: Unexplained weight reduction
• Muscle aches: General body discomfort

Latent and Late (Tertiary) Syphilis

After the secondary stage symptoms resolve, the infection enters a latent phase where there are no visible symptoms, but the bacteria remain in the body. This latent period can last for years or even decades. During early latent syphilis (first year), the infection can still be transmitted to sexual partners. Late latent syphilis is generally not sexually contagious, but the bacteria can still be passed through blood.

Without treatment, approximately 15-30% of people with syphilis will eventually develop tertiary (late) syphilis, which can occur 10-30 years after the initial infection. This stage causes severe damage to internal organs and can be life-threatening. Complications of late syphilis include damage to the heart and blood vessels (cardiovascular syphilis), brain and nervous system damage (neurosyphilis), and formation of large sores called gummas in skin, bones, or organs.

How Is Syphilis Transmitted?

Syphilis spreads primarily through direct contact with syphilis sores during vaginal, anal, or oral sex. The bacteria can enter the body through mucous membranes or tiny breaks in the skin. It can also pass from a pregnant person to their baby (congenital syphilis) and rarely through blood transfusions or shared needles. Syphilis cannot spread through casual contact like touching, sharing utensils, or using public toilets.

The bacterium Treponema pallidum that causes syphilis is highly adapted to human infection and requires direct contact with infected tissue to spread. The primary mode of transmission is sexual contact, but understanding all potential routes helps individuals protect themselves and their partners effectively.

During sexual activity, the bacteria most easily enter the body when mucous membranes (such as those lining the genitals, mouth, and rectum) come into contact with syphilis sores. The sores that appear during primary and secondary syphilis are highly infectious, containing millions of bacteria. Even when these sores are not visible - such as when located inside the vagina, rectum, or throat - they can transmit the infection during sexual contact.

Sexual Transmission Routes

Unprotected vaginal, anal, and oral sex all carry significant risk for syphilis transmission. Anal sex carries particularly high risk because the rectal lining is thin and can easily develop small tears during intercourse, providing entry points for the bacteria. Oral sex, while often perceived as "safer," can definitely transmit syphilis, especially if there are sores in or around the mouth.

Kissing can also transmit syphilis in rare cases when one partner has oral sores, though this is much less common than transmission through genital contact. The bacteria cannot survive long outside the body, which is why transmission requires direct contact rather than indirect exposure through objects or surfaces.

Mother-to-Child Transmission

Syphilis can cross the placenta at any point during pregnancy, with risk increasing as the pregnancy progresses. Congenital syphilis occurs when an infected pregnant person passes the bacteria to their developing baby. This can lead to miscarriage, stillbirth, premature birth, low birth weight, or serious health problems in newborns including developmental delays, seizures, and organ damage.

The good news is that congenital syphilis is entirely preventable through prenatal screening and treatment. All pregnant individuals should be tested for syphilis during their first prenatal visit, with repeat testing recommended for those at higher risk. Treatment with penicillin during pregnancy can cure both the parent and the developing baby.

Other Transmission Routes

While rare, syphilis can also spread through blood transfusions and sharing contaminated needles. In countries with routine blood screening programs, transfusion-related transmission has become extremely uncommon. However, people who inject drugs and share needles remain at increased risk, both for syphilis and other bloodborne infections like HIV and hepatitis.

How Can You Prevent Syphilis?

The most effective prevention against syphilis involves consistent condom use during vaginal, anal, and oral sex. Regular STI testing, especially when entering new sexual relationships, helps detect infection early. Mutual monogamy with a partner who has tested negative also provides protection. For pregnant individuals, prenatal testing and treatment prevents transmission to the baby.

Prevention strategies for syphilis overlap significantly with those for other sexually transmitted infections. While no prevention method is 100% effective except abstaining from sexual contact, a combination of strategies can dramatically reduce your risk of acquiring or transmitting syphilis.

Barrier methods like condoms and dental dams provide substantial protection when used correctly and consistently. However, it's important to understand that syphilis sores can sometimes occur in areas not covered by a condom, so while condoms reduce risk, they don't eliminate it entirely. Despite this limitation, correct condom use remains one of the most effective prevention tools available.

Practical Prevention Strategies

• Use condoms correctly: Use a new condom for every act of vaginal, anal, or oral sex. Ensure the condom is used throughout the entire sexual encounter, not just at the end
• Use dental dams: For oral-vaginal or oral-anal contact, dental dams provide a barrier against infection
• Get tested regularly: If you're sexually active with new or multiple partners, get tested for STIs including syphilis at least annually, or more frequently based on risk factors
• Know your partner's status: Before having sex with a new partner, consider both getting tested together
• Communicate openly: Discuss sexual health openly with partners, including any symptoms or past infections
• Limit sexual partners: Reducing the number of sexual partners decreases exposure risk
• Avoid sex during outbreaks: If you or your partner have visible sores, avoid sexual contact until tested and treated

For individuals at higher risk of syphilis - including men who have sex with men, people with HIV, and those with multiple sexual partners - more frequent testing (every 3-6 months) is recommended. Healthcare providers can offer guidance on appropriate testing frequency based on individual circumstances.

How Is Syphilis Diagnosed?

Syphilis is diagnosed primarily through blood tests that detect antibodies to the bacteria. If you have a visible sore, the doctor may also take a sample directly from the sore for microscopic examination. Blood tests can detect syphilis within 3-6 weeks after infection, though testing may need to be repeated if initial exposure was recent. Testing is confidential, and in many places, free or low-cost.

Getting tested for syphilis is straightforward, confidential, and widely available. If you suspect exposure to syphilis, visiting a healthcare provider, sexual health clinic, or public health department for testing is the essential first step. Many locations offer confidential or anonymous testing services, ensuring your privacy while protecting your health.

There are several types of tests used to diagnose syphilis, each with different strengths and purposes. Understanding these tests can help you know what to expect during the diagnostic process and interpret your results appropriately.

Types of Syphilis Tests

Blood tests (serological tests) are the standard method for diagnosing syphilis. These tests detect antibodies that your immune system produces in response to the infection. There are two main categories:

• Non-treponemal tests (RPR, VDRL): These screening tests detect antibodies produced in response to tissue damage from the bacteria. They're often used for initial screening and to monitor treatment response. However, they can occasionally give false-positive results.
• Treponemal tests (FTA-ABS, TP-PA, EIA): These confirmatory tests detect antibodies specific to Treponema pallidum. Once positive, these tests usually remain positive for life, even after successful treatment.

Modern testing algorithms typically use both types of tests - either screening with a non-treponemal test followed by treponemal confirmation, or increasingly, the reverse sequence. Some rapid point-of-care tests can provide results within 20 minutes, though laboratory-based tests generally take 1-2 weeks for results.

Direct Detection Methods

If you have a visible sore (chancre), the healthcare provider may take a direct sample from the lesion for immediate examination. Using darkfield microscopy, the spirochete bacteria can be directly visualized, providing a definitive diagnosis. This method is particularly useful in primary syphilis when blood tests may not yet be positive. The sample is collected by gently touching the sore with a swab - the procedure is painless.

When to Get Tested

Consider getting tested for syphilis if you:

• Have symptoms of syphilis (painless sore, unexplained rash)
• Have had unprotected sex with a new partner
• Have been notified that a sexual partner has syphilis
• Have other STIs (syphilis often co-occurs with HIV and other infections)
• Are pregnant (all pregnant individuals should be tested early in pregnancy)
• Are a man who has sex with men (annual or more frequent testing recommended)
• Have multiple sexual partners

If your initial test is negative but you had recent potential exposure, repeat testing in 3 months is recommended, as it can take several weeks for antibodies to develop to detectable levels. Testing for other STIs, including HIV, is often recommended at the same time since these infections frequently occur together.

How Is Syphilis Treated?

Syphilis is treated with antibiotics, most commonly penicillin G benzathine given as an intramuscular injection. Early syphilis (primary, secondary, or early latent) typically requires a single injection, while late or unknown-duration syphilis requires three weekly injections. Treatment is highly effective, with cure rates exceeding 95%. After treatment, follow-up blood tests confirm the infection has cleared.

The excellent news about syphilis is that it remains highly curable with appropriate antibiotic treatment, regardless of the stage at which it's diagnosed. Benzathine penicillin G has been the gold standard treatment since the 1940s and remains remarkably effective today. The bacteria have not developed significant resistance to penicillin, making treatment outcomes consistently excellent.

The treatment approach depends on the stage of infection and whether the central nervous system is involved. Early detection and treatment prevent progression to later stages and eliminate the risk of serious complications. Additionally, prompt treatment stops ongoing transmission to sexual partners.

Treatment by Stage

The injection is given in the buttock muscle and, while it can cause temporary discomfort at the injection site, is generally well-tolerated. For those with documented penicillin allergy, alternative antibiotics such as doxycycline can be used, though these require a longer treatment course and may be less effective in certain situations. Pregnant individuals with penicillin allergy may need desensitization to allow penicillin treatment, as alternatives may not adequately protect the developing baby.

Follow-Up After Treatment

After completing treatment for early syphilis, you'll need follow-up blood tests at regular intervals - typically at 3, 6, and 12 months - to confirm the infection has been successfully treated. The non-treponemal test results (RPR or VDRL) should decline over time, indicating treatment success. If titers don't decrease appropriately, retreatment or additional evaluation may be necessary.

During treatment, it's crucial to:

• Abstain from sexual contact until treatment is complete and tests confirm you're no longer infectious (typically at least 1-2 weeks after treatment)
• Notify all recent sexual partners so they can be tested and treated
• Complete all prescribed treatment even if symptoms improve quickly
• Attend all follow-up appointments for repeat testing
• Get tested for HIV if not done recently

What Are the Risks of Syphilis During Pregnancy?

Syphilis during pregnancy poses serious risks to the developing baby, including miscarriage, stillbirth, premature birth, low birth weight, and congenital syphilis - a condition that can cause severe birth defects and developmental problems. However, prenatal screening and treatment with penicillin can cure both the pregnant person and baby, making these outcomes completely preventable.

Congenital syphilis remains a significant global health concern, despite being entirely preventable through routine prenatal screening and treatment. The Treponema pallidum bacteria can cross the placenta at any stage of pregnancy, though the risk of transmission increases as pregnancy progresses. Without treatment, the likelihood of adverse outcomes is very high.

Early prenatal care that includes syphilis screening is critical. In most countries, syphilis testing is a standard part of initial prenatal bloodwork. For pregnant individuals with risk factors (such as lack of prenatal care, multiple partners, previous STIs, or living in areas with high syphilis rates), repeat testing during the third trimester and at delivery may be recommended.

Outcomes of Untreated Syphilis in Pregnancy

When syphilis is not detected and treated during pregnancy, the consequences can be devastating:

• Miscarriage: Loss of pregnancy, particularly in earlier stages
• Stillbirth: Death of the baby after 20 weeks of pregnancy
• Premature birth: Delivery before 37 weeks, with associated complications
• Low birth weight: Babies born smaller than expected
• Congenital syphilis: Babies born with active infection

Babies born with congenital syphilis may appear healthy at birth but develop symptoms within the first few weeks of life. Early signs include skin rashes, fever, enlarged liver and spleen, jaundice, and anemia. Without treatment, late manifestations can include bone abnormalities, dental problems, vision and hearing loss, and neurological damage.

Treatment During Pregnancy

Penicillin is the only antibiotic proven to treat both the pregnant person and prevent congenital syphilis. It effectively crosses the placenta to treat the developing baby. Treatment should begin as soon as syphilis is diagnosed during pregnancy. For those with documented penicillin allergy, desensitization followed by penicillin treatment is recommended, as alternative antibiotics do not adequately protect the fetus.

With appropriate treatment, the outcomes are excellent. Babies whose mothers receive adequate treatment during pregnancy rarely develop congenital syphilis. This makes prenatal screening one of the most cost-effective public health interventions available.

What Happens If Syphilis Goes Untreated?

Untreated syphilis can progress to serious complications affecting the heart, brain, nerves, eyes, and other organs. Late (tertiary) syphilis develops in 15-30% of untreated cases, typically 10-30 years after initial infection. Complications include cardiovascular damage (aortic aneurysm, heart valve problems), neurosyphilis (dementia, paralysis, stroke), and gummatous syphilis (destructive lesions in any organ). These complications can be fatal.

While early syphilis is easily treated with excellent outcomes, the consequences of prolonged untreated infection can be severe and sometimes irreversible. Understanding these potential complications underscores the importance of testing and early treatment. Even when complications have developed, treatment can prevent further progression, though it cannot reverse damage that has already occurred.

Neurosyphilis

Syphilis can invade the central nervous system at any stage of infection, but symptomatic neurosyphilis typically occurs in late syphilis. The bacteria can cause inflammation of the brain and spinal cord membranes (meningitis), stroke due to blood vessel inflammation, progressive dementia, and general paresis - a syndrome of personality changes, dementia, and physical symptoms. Tabes dorsalis, a late form of neurosyphilis, causes progressive sensory loss, shooting pains, and difficulty walking.

Ocular syphilis (affecting the eyes) and otosyphilis (affecting the ears) can occur at any stage and may cause vision changes, blindness, hearing loss, and tinnitus. These complications require prompt treatment to prevent permanent damage.

Cardiovascular Syphilis

Syphilis can damage the large blood vessels, particularly the aorta - the body's main artery. This can lead to aortic aneurysm (a dangerous bulging of the vessel wall that can rupture), aortic valve problems, and narrowing of the coronary arteries. Cardiovascular syphilis typically develops 10-25 years after initial infection and can be life-threatening.

Gummatous Syphilis

Gummas are soft, tumor-like balls of inflammation that can develop in the skin, bones, liver, or any organ. While not typically life-threatening, they can cause significant destruction of affected tissues. With treatment, gummas usually heal, but scarring may persist.

Increased HIV Risk

Having syphilis significantly increases the risk of acquiring and transmitting HIV. Syphilis sores provide an entry point for HIV, and the inflammation caused by syphilis activates immune cells that HIV targets. Studies suggest that having syphilis increases HIV transmission risk 2-5 fold. This is why testing for both infections is recommended, and why treating syphilis is an important component of HIV prevention strategies.

Why Is Partner Notification Important?

Partner notification is essential for controlling syphilis spread and protecting the health of sexual contacts. All recent sexual partners of someone diagnosed with syphilis need to be informed so they can be tested and treated if necessary. This prevents reinfection of the treated person, stops ongoing transmission chains, and identifies infections that might otherwise go undetected. Many clinics offer confidential partner notification services.

When someone is diagnosed with syphilis, identifying and notifying their sexual partners is a critical public health measure. This process, sometimes called "contact tracing," helps break the chain of transmission and ensures that others who may be infected receive timely testing and treatment. Partner notification is a cornerstone of STI control programs worldwide.

In many countries, syphilis is a reportable disease, meaning healthcare providers must notify public health authorities of diagnoses. These authorities can assist with partner notification while maintaining the privacy of the person who was initially diagnosed. Partners are informed of potential exposure without being told who named them.

How Partner Notification Works

You have options for how partners are notified:

• Self-notification: You contact partners yourself to inform them of potential exposure
• Provider referral: Healthcare providers or public health staff contact partners on your behalf, without revealing your identity
• Combination approach: You notify some partners, and health services help with others

Partners should be tested regardless of whether they have symptoms, as syphilis can be asymptomatic. The "look-back" period - how far back partners need to be notified - depends on the stage of syphilis at diagnosis. For primary syphilis, partners from the previous 3 months should be notified; for secondary syphilis, 6 months; and for early latent syphilis, up to 1 year.