Syphilis – Causes, Signs and symptoms


Also called: Treponema Pallidum Infection

Reviewed By:
Vikram Tarugu, M.D., AGA, ACG


Syphilis is a bacterial infection, usually considered a sexually transmitted disease. Transmitted through personal contact, it usually first appears in the genitals or on other parts of the body that have had contact with an infected person.

Syphilis can be successfully treated with antibiotics. However, if left untreated, a syphilis infection can eventually infect the heart, brain and central nervous system.

Syphilis occurs in three stages: primary, secondary and tertiary. Primary syphilis is the initial infection. It often appears as a single, non-painful ulcer or sore on the genitals. Secondary syphilis may appear weeks later with a variety of symptoms, including rashes, wart-like areas, swollen lymph nodes and hair loss.

For both primary and secondary syphilis, symptoms can disappear without treatment. It is important to note, however, that people are still infected and can transmit the disease at this time. Not every person at these stages of infection progress to the tertiary stage. After the secondary stage, syphilis enters a latent period, which may last for years or decades. In addition, treatment at the primary or secondary stage of infection prevents the progression of the disease.

Tertiary syphilis, when it appears, includes symptoms that affect many body systems and can lead to dementia (loss of mental functioning) and death. Treatment at this stage can stop the infection, but cannot reverse damage to the organs.

Various physical evaluations, tissue samples and blood tests are used to diagnose syphilis and rule out other conditions. Once the disease is diagnosed and the stage of the disease is determined, syphilis is treated and cured with antibiotics. The risk of contracting syphilis can be reduced by using safe sex practices, such as using latex condoms and avoiding sexual contact with multiple sex partners or high-risk sex partners.

Although it is still a serious health risk, the advent of antibiotics has made syphilis a much less devastating disease than it has been in the past.

About syphilis

Syphilis is an infectious disease, usually spread through sexual contact. Symptoms of the disease appear in readily identifiable stages, but not all people progress through each stage. This is true even if the disease is left untreated. Syphilis can take years to move through these stages, with up to 20 or 30 years passing before the last stage of the disease develops.

Syphilis is divided into three stages – primary, secondary and tertiary – with a lengthy latent period between the last two. Primary and secondary syphilis occur within a year of initial infection.

Syphilis spreads when the bacteria (called Treponema pallidum) in a syphilis sore (chancre) comes into contact with an open cut, lesion or opening in a mucous membrane. This usually occurs in the genital area during sexual contact. Although syphilis bacteria multiply at a relatively slow rate, these bacteria may simultaneously spread throughout the body via the lymphatic system. Because of this, symptoms of syphilis can appear in several places in the body and are often confused with other conditions.  

Syphilis can spread through vaginal, anal and oral sex. Close contact such as kissing may also spread the disease, if sores or cuts are present in the mouth. Injecting intravenous drugs with an infected needle can also transmit syphilis. The syphilis bacteria cannot survive on inanimate objects and so the disease cannot be spread via pools, hot tubs, doorknobs, toilet seats or other such objects.

After infection, the primary stage of syphilis (usually a single sore at the infection site) may not even be noticeable. In its secondary stage, syphilis presents symptoms that are common with various other diseases (e.g., rash, fever, weight loss). In both stages, the symptoms may resolve without treatment. However, even when symptoms appear to be healing, people are still infectious and can spread the disease.

After its secondary stage, syphilis may enter a long latent period, when patients have no symptoms. The final tertiary stage may begin many years later and affect the heart, brain, spinal cord or skin. Many people with syphilis never progress to the secondary or tertiary stages.

The complications of syphilis are associated with the tertiary stage of infection. Many body systems may be affected and, if the syphilis is left untreated, it may eventually cause death. Syphilis at every stage can affect pregnant women, who may pass the disease to their fetus. Syphilis can also cause miscarriage or stillbirth.

People with human immunodeficiency virus (HIV) and the associated acquired immune deficiency syndrome (AIDS) also experience complications with syphilis. HIV-positive patients are more likely to be infected with syphilis. Also, people with syphilis are more likely to become infected with HIV due to the presence of skin lesions, which can allow the virus entry into the body. Additionally, people with HIV or AIDS are more likely to experience the neurological symptoms associated with tertiary syphilis at an earlier stage than people without HIV or AIDS. The Centers for Disease Control and Prevention (CDC) estimates that individuals with syphilis have between two to five times greater risk of acquiring HIV than people without syphilis.

Reports of primary and secondary syphilis cases in the United States decreased by almost 90 percent throughout the 1990s and into 2000, to the lowest number since the CDC began recording the disease in 1941. According to the CDC, more than 34,000 new cases of syphilis were reported in 2003. From 2000 to 2004, syphilis cases increased, but only among men. Some of that increase may be attributed to reported outbreaks of syphilis among men who have sex with men. Syphilis rates for women continued to decline in that time period. Syphilis rates among African-Americans declined as well; however, this population remains the most affected by the disease.

Types and differences of syphilis

Syphilis is identified by its stages. There are three major stages, with a potentially long period of latency between the second and third stage. Some people with syphilis may experience one stage but never progress to subsequent stages of the disease.

The progression of a syphilis infection may include:

  • Primary syphilis. The first phase of syphilis usually appears as one chancre (sore) at the site that was in contact with an infected partner. The chancre can appear between 10 and 90 days after contact, although the usual time is about 21 days. Syphilis chancres usually heal within three to six weeks, even if untreated (although the person remains infected). The disease can be transmitted from any contact with the chancre. This sore or ulcer is characterized as nonpainful, unlike ulcers associated with other types of diseases.
  • Secondary syphilis. Without adequate treatment, primary syphilis progresses to secondary syphilis. Symptoms are reversible with treatment at this stage. Secondary syphilis may occur from six weeks to six months after the primary infection, sometimes while the original chancre is still present. Secondary syphilis includes numerous symptoms, many of which mimic other diseases. Not all patients with primary syphilis progress to the secondary stage. In addition, not all patients with secondary syphilis can recall a primary infection, and they may not have noticed any symptoms. As with primary syphilis, the symptoms in this stage usually resolve without treatment, often within six weeks. However, the infection may be widespread at this point. Physical contact between an infected area and other broken skin or membranes in the body can spread the disease.
  • Latent stage. After the secondary stage, the patient may have brief relapses of symptoms and then syphilis may retreat for years or decades. Some people experience no further symptoms. Unless treated, the patient remains infected and can still transmit the disease in the early part of the latent period, within one year from the time of initial infection. More than two years after the start of the latent phase, patients may have no symptoms and are often not infectious.
  • Tertiary syphilis. Symptoms of tertiary syphilis may develop years or decades after initial infection. At this advanced stage, the syphilis bacteria have spread throughout the body, and frequently involve the skin, cardiovascular system or central nervous system. The infection can still be treated, but damage to organs cannot be reversed. At this stage, syphilis can lead to death. Syphilis cannot be transmitted during the tertiary stage.

Congenital syphilis occurs when babies contract syphilis from their mother either through the placenta or when passing through the vagina at birth. Untreated syphilis during pregnancy results in stillbirth or death of the infant in 40 percent of the cases, according to the Centers for Disease Control and Prevention (CDC). The CDC also reports that women who acquired syphilis and were untreated in the four years preceding pregnancy passed it on to their baby in 70 percent of the cases. Infants of pregnant women adequately treated with penicillin during pregnancy have a minimal risk of developing congenital syphilis. All pregnant women who receive prenatal care in the United States are screened for syphilis.

Treatment of syphilis in pregnant women lowers the risk of the fetus contracting syphilis. Even when the mother is not treated, surviving infants with congenital syphilis can usually be successfully treated after birth. If newborns who have contracted congenital syphilis are not treated, it can lead to complications such as blindness, deafness, neurological problems and abnormalities of the teeth and nose.

Risk factors and causes of syphilis

Risk factors are certain elements that increase the likelihood of a person developing a disease or condition. However, not everyone with risk factors will develop syphilis. Likewise, some people who have no risk factors develop the disease. Some risk factors associated with syphilis include:

  • Age. Syphilis is most common among sexually active young people, with most cases occurring among men ages 35 to 39 and women ages 20 to 24.
  • Sexual activity. People who have unprotected sex, have multiple sex partners or high-risk or infected sex partners are at greater risk.
  • HIV infection. People with HIV are at greater risk of developing syphilis.
  • Location. Approximately 79 percent of counties in the United States reported no cases of primary or secondary syphilis to the Centers for Disease Control and Prevention (CDC) in 2004. According to the CDC, most of the counties in the United States with primary or secondary syphilis were in the South. People who have any risk factors for sexual activity listed above and who live in areas with reported cases of syphilis are at greater risk.

Signs and symptoms of syphilis

The signs and symptoms of syphilis vary depending on the stage of the disease. Symptoms may go unnoticed, especially for primary syphilis, or may be attributed to other causes.

The main symptom of primary syphilis is a painless sore (chancre) at the site that had contact with an infected partner. Common infection sites include the vagina, penis, scrotum, cervix, vulva or anal area. Chancres are flat or slightly raised and do not itch. The chancre may not be noticed or may be in a location the person cannot see. Nevertheless, the disease can still be transmitted. From the chancre, bacteria spread rapidly into the system. Chancres usually heal within a few weeks with no treatment. Enlarged lymph nodes in the groin may also be present.

The secondary stage of the disease has numerous symptoms and can affect many body areas. They may appear as the initial chancre is fading or several weeks later. Symptoms of secondary syphilis include:

  • Rash. Occurs throughout the trunk and extremities. The rash may appear as coin-sized lesions that do not itch, a rash with pustules (pus-filled sores), or an itchy rash. A rash on the palms of the hands and soles of the feet is characteristic of syphilis. In some cases, the rash is very faint or is similar to rashes caused by other infections. As a result, it may not be noticed. Because of the bacteria level in these lesions, any physical contact (sexual or nonsexual) with a broken sore can transmit the disease.
  • Condyloma lata. Gray or white wart-like mucous patches that form in skin folds or moist areas inside or outside the body, such as under the breast, in the groin or in the armpits.
  • Patchy hair loss on the head and other parts of the body.
  • Swollen lymph nodes and sore throat.
  • Fever.
  • Headache and muscle aches.
  • Fatigue.
  • Weight loss.

Other less common symptoms of secondary syphilis include gastrointestinal upset, hepatitis or kidney disease. Many of the symptoms during this stage of syphilis are common to other diseases as well. The symptoms will disappear with or without treatment.

Signs and symptoms of tertiary syphilis depend on the body system involved. This latest stage of syphilis may affect any or all of these areas of the body:

  • Central nervous system (neurosyphilis). Syphilis may affect many parts of the nervous system, including the meninges, brain, spinal cord, eyes or ears. Symptoms may include uncoordinated muscle movement, meningitis, incontinence, numbness, paralysis, blindness, deafness, and personality changes such as paranoia, mood swings and eventually dementia (loss of mental functioning). Sometimes neurosyphilis symptoms can appear as part of secondary syphilis, especially in people with HIV or AIDS. Neurosyphilis is the most common sign of tertiary syphilis and is the most difficult to treat.
  • Skin, bones and liver. Soft ulcers and lesions (gumma) found inside or outside the body. These are more common among patients with HIV infection.
  • Cardiovascular system. Inflammation affects the aorta, the body’s largest artery that transports blood from the heart. There may also be problems with the aortic valve, which opens between the heart and aorta.

Infants born with congenital syphilis may have symptoms at birth, but many develop them between two weeks and three months after birth. Signs and symptoms of congenital syphilis may include:

  • Skin ulcers
  • Rashes
  • Fever
  • Weakened crying
  • Swollen liver or spleen
  • Jaundice (yellowing of the skin, whites of the eyes, nail beds and/or mucous membranes)
  • Anemia (a lack of red blood cells and/or the iron-rich molecule in red blood cells [hemoglobin] that carries oxygen throughout the body and gives blood its red color)
  • Deformity of the bridge of the nose (saddle nose)

Symptoms in infants are usually detected during well-child visits (routine medical examinations). However, when congenital syphilis is left untreated, complications during childhood can occur. These may include abnormally shaped teeth, vision loss, deafness and other complications associated with congenital syphilis.

Diagnosis methods for syphilis

Diagnosis begins with a complete medical history(including sexual history) and a physical examination. Based on those results, physicians use several types of tests to diagnose syphilis. In many cases, physicians must repeat diagnostic tests because the disease is less detectable in its early stages. Some diagnostic methods are more effective than others, depending on the stage of the disease. Physicians frequently use some or all of these methods to diagnose syphilis.

  • Visualization. A physician can usually identify the chancres (sores) of primary syphilis on sight.
  • Dark field imaging. A specialized microscope is used to identify the syphilis bacteria. A sample from a chancre or lesion is used or fluid is taken from a lymph node. This test usually involves swabbing a chancre, infected skin or mucous membrane, or using a needle to obtain fluid from the chancre or an infected lymph node. The liquid or sample is placed on a slide and viewed through a special dark-field microscope. This method is effective for detecting primary and secondary syphilis.
  • Screening tests. Physicians may use a test that screens for a certain antibody not related to syphilis (nontreponemal tests). These include the venereal disease research laboratory (VDRL) or rapid plasma reagin (RPR) tests. Both tests may use blood or spinal fluid, but blood is much more common. Spinal fluid testing is usually only performed in cases of suspected tertiary syphilis. To obtain spinal fluid, the physician performs a spinal tap by inserting a needle into the lower back and collecting the cerebrospinal fluid. These tests are useful for detecting tertiary syphilis, but not primary or secondary syphilis. They may also produce false positives. Many other conditions, including pneumonia, blood transfusions or pregnancy, may produce positive reactions on the VDRL and RPR tests.
  • Treponemal antibody tests. If the screening tests have positive reactions, a physician may recommend a blood test to detect the presence of antibodies to the Treponema pallidum bacteria. These blood tests include:
    • Fluorescent treponemal antibody absorption (FTA–ABS). May also be used with spinal fluid.
    • Microhemagglutination assay for antibodies to Treponema pallidum (MHA–TP). This test is rarely used.
    • Treponema pallidum particle agglutination (TPPA).

These tests are accurate except in the first few weeks after infection. In addition, a patient treated for a previous case of syphilis will continue to test positive because they have antibodies to the disease but can still be re-infected. In these cases, re-infection is determined by a rise in the level of certain antibodies. Syphilis testing may need to be repeated if the initial results are uncertain or there is further exposure through unprotected sexual intercourse.

Treatment options for syphilis

Syphilis is treated with antibiotics. Injections of penicillin, either in a single shot or provided over several weeks, usually cure the disease. Certain other antibiotics are effective against syphilis for patients with penicillin allergies. However, penicillin is the only option for pregnant women. A pregnant woman with syphilis who is allergic to penicillin must go through desensitization procedures (a process that reduces or eliminates a sensitivity to certain drugs) so that treatment with penicillin can begin.

Some patients have a reaction to syphilis treatment, especially those with secondary syphilis. Reactions (such as the Jarisch-Herxheimer reaction) often occur within a day after treatment and may feel like a worsening of syphilis symptoms, including fever, aches, headache and flu-like symptoms. The reaction usually passes within a day. Reactions may be the result of a large number of bacteria in the body dying at the same time.

After treatment, syphilis patients should have follow-up screening tests at regular intervals (six and 12 months) or until the nontreponemal tests – the tests that screen for a certain antibody not related to syphilis – come back negative. Pregnant women treated for syphilis should have blood tests for syphilis each month for the remainder of their pregnancy. Women who tested negative for syphilis early in their pregnancy should be retested nearer to delivery if there has been additional risk of exposure to the disease.

People treated for syphilis should abstain from sexual activity until their sores have healed completely, and they are informed by their physician that they are no longer infectious. This may take two to three months.

Sexual partners should be notified of the diagnosis so they may seek medical testing and treatment. Patients diagnosed with primary syphilis should notify all sexual contacts from the previous three months. Those people diagnosed with secondary syphilis should notify all sexual partners from the past year. Sexual activity with these partners should stop until they have been tested and, if tests are positive, treated for the infection. In the United States, physicians must report all cases of syphilis to local health authorities and the Centers for Disease Control and Prevention (CDC).

Prevention methods for syphilis

Safe sex measures that help prevent the spread of other sexually transmitted diseases (STDs) can reduce the risk of contracting syphilis. These include sexual monogamy, reducing the number of sexual partners and avoiding sex with higher risk partners (those with multiple partners or intravenous drug users). Abstaining from all sexual activity is the only way to completely prevent syphilis.

Latex condoms used consistently and correctly during every sexual act reduce the risk of syphilis transmission. However, condoms only protect the areas they cover. Syphilis lesions (chancres) in areas not covered by a condom (e.g., scrotum, vulva or anal area) can still spread the disease. Dental dams can minimize transmission during oral sex.

The Centers for Disease Control and Prevention recommends that pregnant women be tested for syphilis as part of their first prenatal care visit with a physician. People with risk factors for the disease or with multiple sex partners may want to be tested regularly. Every person should discuss the risks of all STDs with a physician.

Questions for your doctor regarding syphilis

Preparing questions in advance can help patients to have more meaningful discussions with their physician regarding their conditions. Patients may wish to ask their doctor the following questions related to syphilis:

  1. I am having unprotected sex. Should I get tested for syphilis?
  2. What tests are needed to confirm I have syphilis? How will I need to prepare for those tests?
  3. What is the stage of my syphilis?
  4. Are there medications to cure syphilis? What are the side effects associated with these medications?
  5. When will I see improvement in my condition?
  6. Will tests confirm that the syphilis is cured?
  7. How long must I abstain from sexual relations?
  8. Does syphilis affect my ability to get pregnant?
  9. What can I do to avoid another case of syphilis?
  10. Will my sexual partner be affected by my case of syphilis?
  11. I am pregnant. How will my case of syphilis affect my baby? What will be done to prevent infection in my baby?
Scroll to Top