Syphilis is a sexually transmitted disease caused by infection with the Treponema pallidum bacteria. 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, it can eventually infect the heart, brain and central nervous system.

Syphilis progresses in three stages. Primary syphilis, the first stage of the disease, often appears as a single non-painful ulcer or sore on the genitals. Secondary syphilis may appear weeks later and can present with a variety of symptoms, including rashes, wartlike areas, swollen lymph nodes and hair loss.

For both primary and secondary syphilis, symptoms disappear without treatment. However, it is important to note that people are still infected and can transmit the disease at this time. Every person with these stages of syphilis does not progress to the succeeding tertiary stage. After the secondary stage, syphilis enters a latent period, which may last for years or decades.

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

Syphilis can also be transmitted during pregnancy or childbirth from an infected mother to her unborn infant (congenital syphilis). The disease may cause miscarriages or stillbirths. In surviving infants, complications of congenital syphilis may include blindness, deafness, neurological problems and abnormalities of the teeth and nose.

Once the disease is diagnosed, typically by examination of tissue samples and blood tests, and the stage of the disease is determined, syphilis is treated and cured with antibiotics. The risk of syphilis transmission can be reduced by using safe sex practices, such as using latex condoms and avoiding multiple sex partners or high-risk sex partners.

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 until the late stages of the disease.

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 areas during sexual contact. 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 be spread through pools, hot tubs, doorknobs, toilet seats or other inanimate objects.

After infection, the primary stage of syphilis (usually a single chancre 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 resolve without treatment. However, even when symptoms appear to be healing, people can still 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 tertiary syphilis. They can affect many body systems and if left untreated, eventually cause death. Syphilis in every stage also affects pregnant women, who can pass the disease to their fetus. In addition to complications (e.g., vision and hearing loss) for children born to mothers with syphilis, the disease may also cause miscarriages or stillbirths.

Like other sexually transmitted diseases, infection with syphilis may also facilitate transmission of human immunodeficiency virus (HIV). 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, 33,401 new cases of syphilis were reported in 2004. From 2000 to 2005, the overall increase in primary and secondary syphilis cases was observed mainly among men. Some of that increase may be attributed to reported outbreaks of syphilis among men who have sex with men. However, syphilis rates for women, which were previously declining, increased 12.5 percent in that time period (from 0.8 cases to 0.9 cases for every 100,000 women). 

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 women with syphilis may experience one stage but never progress to the subsequent stages of the disease.

• Primary syphilis. The first phase of syphilis usually appears as one chancre (sore) at the site that was in contact with an infected partner. This sore or ulcer is characterized as non-painful, unlike ulcers associated with other types of diseases. 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. The disease can be transmitted from any contact with the chancre.
• Secondary syphilis. Without adequate treatment, primary syphilis progresses to secondary syphilis. This stage may occur from six weeks to six months after the primary infection, sometimes while the original chancre is still present. Secondary syphilis has 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 the 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 transmit 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 women experience no further symptoms. The patient 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 later. At this advanced stage, the syphilis bacteria have spread throughout the body, and frequently involve the skin, cardiovascular system or central nervous system. At this stage, the infection may lead to death. Syphilis cannot be transmitted at this stage. The infection can still be treated, but damage to organs cannot be reversed.

Pregnant women with syphilis who do not receive appropriate treatment can risk infecting their unborn children (congenital syphilis). Babies can contract syphilis from their mother either through the placenta or when passing through the vagina (birth canal) during 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 not treated 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 the antibiotic 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 treated successfully after birth.

Infants born with 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
• Yellowing of the skin, whites of the eyes, nail beds and/or mucous membranes (jaundice)
• Anemia (low red blood cell count)
• Deformity of the bridge of the nose (saddle nose)

Symptoms in infants are usually detected during well-child visits (routine medical examinations typically with a pediatrician). However, when congenital syphilis is left untreated, serious complications during childhood can occur. These can include blindness, deafness, neurological problems and abnormalities of the teeth and nose.

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 women ages 20 to 24 and men ages 35 to 39.
  
  
• 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. 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.

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.

Primary syphilis. The main symptom of primary syphilis is a painless sore (chancre) at the site that had contact with an infected partner. Common infection sites in women include the vagina, 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 such as the cervix. Nevertheless, the disease can still be transmitted. From the chancre, bacteria spread rapidly in the system. Chancres usually heal within a few weeks with no treatment. Enlarged lymph nodes in the groin may also be present.

Secondary syphilis. This stage of the disease has numerous symptoms. They may appear as the initial chancre is fading or several weeks later. Symptoms include:

• Rash. Occurs throughout the trunk and extremities. The rash may appear as coin-sized lesions that do not itch. 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 wartlike 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.

Tertiary syphilis. Signs and symptoms of this late stage of the disease depend on the body system involved. They may affect any or all of these areas:

• Skin, bones and liver. Soft ulcers and lesions (gumma) found inside or outside the body. These are more common among patients with HIV infection.
  
  
• 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 loss of mental functioning (dementia). Sometimes neurosyphilis symptoms can appear as part of secondary syphilis. Neurosyphilis is the most common form of the tertiary stage and is the most difficult to treat.
  
  
• 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.

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 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, the patient will have a blood test that detects antibodies to the Treponema pallidum bacteria. These include the fluorescent treponemal antibody absorption (FTA-ABS) test, which may also be used with spinal fluid, and the Treponema pallidum particle agglutination (TPPA) test.

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 antibody titer.

Syphilis testing may need to be repeated if the initial results are uncertain or there is further exposure through unprotected sexual intercourse.

Syphilis is treated with antibiotics. Injections of penicillin, either single or given 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 (medical procedure to reduce or eliminate sensitivity to certain drugs necessary for a patient) so she may take penicillin.

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 the syphilis symptoms, including fever, aches, headache and flu-like symptoms. The reaction passes within a day. It may be the result of so many 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 come back negative. Pregnant women treated for syphilis should have blood tests 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 with secondary syphilis should notify all partners from the past year. In the United States, physicians must report all cases of syphilis to local health authorities and the Centers for Disease Control and Prevention (CDC).

Safe sex measures that help prevent the spread of other sexually transmitted diseases (STDs) reduce the risk for syphilis transmission. 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 help reduce the risk of syphilis transmission. However, condoms only protect the areas they cover. Syphilis 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 CDC recommends that pregnant women get tested for syphilis as part of their first prenatal care visit with a physician. People with other risk factors for the disease or with multiple partners may want to be tested regularly. Women should discuss their risks for all STDs with their physician, preferably a gynecologist.

Preparing questions in advance can help patients have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor or healthcare professional the following questions about syphilis:

1. I’m 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’m pregnant. How will my case of syphilis affect my baby? What will be done to prevent infection in my baby?