Syphilis - CDC Fact Sheet (Detailed)
Detailed fact sheets are intended for physicians and individuals with specific questions about sexually transmitted diseases. Detailed fact sheets include specific testing and treatment recommendations as well as citations so the reader can research the topic more in depth.
What is syphilis?
Syphilis is a sexually transmitted disease (STD) caused by the bacterium Treponema pallidum. Syphilis can cause long-term complications if not adequately treated.
How common is syphilis?
During 2013, there were 56,471 reported new cases of syphilis, compared to 47,352 estimated new diagnoses of HIV infection and 333,004 cases of gonorrhea in 2013.1, 2 Of syphilis cases, 17,535 were of primary and secondary (P&S) syphilis, the earliest and most transmissible stages of syphilis. During the 1990s, syphilis primarily occurred among heterosexual men and women of racial and ethnic minority groups; during the 2000s, however, cases increased among men who have sex with men (MSM).3 MSM accounted for 75% of all P&S syphilis cases in 2013.
Congenital syphilis (syphilis passed from pregnant women to their babies) continues to be a concern in the United States. During 2013, 348 cases of congenital syphilis were reported, compared to an estimated 107 cases of perinatal HIV infection during 2013. 1 Congenital syphilis rates were 10.4 times and 3.5 times higher among infants born to black and Hispanic mothers (29.0 and 9.7 cases per 100,000 live births, respectively) compared to white mothers (2.8 cases per 100,000 live births).
How do people get syphilis?
Syphilis is transmitted from person to person by direct contact with a syphilitic sore, known as a chancre. Chancres occur mainly on the external genitals, vagina, anus, or in the rectum. Chancres also can occur on the lips and in the mouth. Transmission of syphilis occurs during vaginal, anal, or oral sex. Pregnant women with the disease can transmit it to their unborn child.
How quickly do symptoms appear after infection?
The average time between infection with syphilis and the start of the first symptom is 21 days, but can range from 10 to 90 days.
What are the signs and symptoms in adults?
Syphilis has been called “The Great Pretender”, as its symptoms can look like many other diseases. However, syphilis typically follows a progression of stages that can last for weeks, months, or even years:
The appearance of a single chancre marks the primary (first) stage of syphilis symptoms, but there may be multiple sores. The chancre is usually firm, round, and painless. It appears at the location where syphilis entered the body. These painless chancres can occur in locations that make them difficult to find (e.g., the vagina or anus). The chancre lasts 3 to 6 weeks and heals regardless of whether a person is treated or not. However, if the infected person does not receive adequate treatment, the infection progresses to the secondary stage.
Skin rashes and/or mucous membrane lesions (sores in the mouth, vagina, or anus) mark the second stage of symptoms. This stage typically starts with the development of a rash on one or more areas of the body. Rashes associated with secondary syphilis can appear when the primary chancre is healing or several weeks after the chancre has healed. The rash usually does not cause itching. The characteristic rash of secondary syphilis may appear as rough, red, or reddish brown spots both on the palms of the hands and the bottoms of the feet. However, rashes with a different appearance may occur on other parts of the body, sometimes resembling rashes caused by other diseases. Sometimes rashes associated with secondary syphilis are so faint that they are not noticed. Large, raised, gray or white lesions, known as condyloma lata, may develop in warm, moist areas such as the mouth, underarm or groin region. In addition to rashes, symptoms of secondary syphilis may include fever, swollen lymph glands, sore throat, patchy hair loss, headaches, weight loss, muscle aches, and fatigue. The symptoms of secondary syphilis will go away with or without treatment, but without treatment, the infection will progress to the latent and possibly late stages of disease.
Latent and Late Stages
The latent (hidden) stage of syphilis begins when primary and secondary symptoms disappear. Without treatment, the infected person will continue to have syphilis infection in their body even though there are no signs or symptoms. Early latent syphilis is latent syphilis where infection occurred within the past 12 months. Late latent syphilis is latent syphilis where infection occurred more than 12 months ago. Latent syphilis can last for years.
The late stages of syphilis can develop in about 15% of people who have not been treated for syphilis, and can appear 10–20 years after infection was first acquired. In the late stages of syphilis, the disease may damage the internal organs, including the brain, nerves, eyes, heart, blood vessels, liver, bones, and joints. Symptoms of the late stage of syphilis include difficulty coordinating muscle movements, paralysis, numbness, gradual blindness, and dementia. This damage may be serious enough to cause death.
Syphilis can invade the nervous system at any stage of infection, and causes a wide range of symptoms varying from no symptoms at all, to headache, altered behavior, and movement problems that look like other neurologic diseases, such as Parkinson’s or Huntington’s disease. 7 This invasion of the nervous system is called “neurosyphilis.”
HIV infection and syphilis symptoms
Individuals who are HIV-positive can develop symptoms very different from the symptoms described above, including hypopigmented skin rashes. 5 HIV can also increase the chances of developing syphilis with neurological involvement. 6
How does syphilis affect a pregnant woman and her baby?
The syphilis bacterium can infect the baby of a woman during her pregnancy. All pregnant women should be tested for syphilis at the first prenatal visit. The syphilis screening test should be repeated during the third trimester (28 to 32 weeks gestation) and at delivery in women who are at high risk for syphilis, live in areas of high syphilis morbidity, are previously untested, or had a positive screening test in the first trimester. 7
Depending on how long a pregnant woman has been infected, she may have a high risk of having a stillbirth (a baby born dead) or of giving birth to a baby who dies shortly after birth; untreated syphilis in pregnant women results in infant death in up to 40 percent of cases. 8 Any woman who delivers a stillborn infant after 20 week’s gestation should also be tested for syphilis.
An infected baby born alive may not have any signs or symptoms of disease. However, if not treated immediately, the baby may develop serious problems within a few weeks. Untreated babies may become developmentally delayed, have seizures, or die. All babies born to mothers who test positive for syphilis during pregnancy should be screened for syphilis and examined thoroughly for evidence of congenital syphilis. 7
For pregnant women only penicillin therapy can be used to treat syphilis and prevent passing the disease to her baby; treatment with penicillin is extremely effective (success rate of 98%) in preventing mother-to-child transmission. 9 Pregnant women who are allergic to penicillin should be referred to a specialist for desensitization to penicillin.
How is syphilis diagnosed?
The definitive method for diagnosing syphilis is visualizing the spirochete via darkfield microscopy. This technique is rarely performed today because it is a technologically difficult method. Diagnoses are thus more commonly made using blood tests. There are two types of blood tests available for syphilis: 1) nontreponemal tests and 2) treponemal tests.
Nontreponemal tests (e.g., VDRL and RPR) are simple, inexpensive, and are often used for screening. However, they are not specific for syphilis, can produce false-positive results, and, by themselves, are insufficient for diagnosis. VDRL and RPR should each have their antibody titer results reported quantitatively. Persons with a reactive nontreponemal test should receive a treponemal test to confirm a syphilis diagnosis. This sequence of testing (nontreponemal, then treponemal test) is considered the “classical” testing algorithm.
Treponemal tests (e.g., FTA-ABS, TP-PA, various EIAs, chemiluminescence immunoassays, immunoblots, and rapid treponemal assays) detect antibodies that are specific for syphilis. Treponemal antibodies appear earlier than nontreponemal antibodies and usually remain detectable for life, even after successful treatment. If a treponemal test is used for screening and the results are positive, a nontreponemal test with titer should be performed to confirm diagnosis and guide patient management decisions. Based on the results, further treponemal testing may be indicated. For further guidance, please refer to the 2015 STD Treatment Guidelines. 7 This sequence of testing (treponemal, then nontreponemal, test) is considered the “reverse” sequence testing algorithm.Reverse sequence testing can be more convenient for laboratories, but its clinical interpretation is problematic, as this testing sequence can identify individuals not previously described (e.g., treponemal test positive, nontreponemal test negative), making optimal management choices difficult. 10
Special note: Because untreated syphilis in a pregnant woman can infect and possibly kill her developing baby, every pregnant woman should have a blood test for syphilis. All women should be screened at their first prenatal visit. For patients who belong to communities and populations with high prevalence of syphilis and for patients at high risk, blood tests should also be performed during the third trimester (at 28–32 weeks) and at delivery. For further information on screening guidelines, please refer to the 2015 STD Treatment Guidelines. 7
All infants born to mothers who have reactive nontreponemal and treponemal test results should be evaluated for congenital syphilis. A quantitative nontreponemal test should be performed on infant serum and, if reactive, the infant should be examined thoroughly for evidence of congenital syphilis. Suspicious lesions, body fluids, or tissues (e.g., umbilical cord, placenta) should be examined by darkfield microscopy, PCR testing, and/or special stains. Other recommended evaluations may include analysis of cerebrospinal fluid by VDRL, cell count and protein, CBC with differential and platelet count, and long-bone radiographs. For further guidance on evaluation of infants for congenital syphilis, please refer to the 2015 STD Treatment Guidelines. 7
What is the link between syphilis and HIV?
Genital sores caused by syphilis make it easier to transmit and acquire HIV infection sexually. There is an estimated 2- to 5-fold increased risk of acquiring HIV if exposed to that infection when syphilis is present. 11
Ulcerative STDs that cause sores, ulcers, or breaks in the skin or mucous membranes, such as syphilis, disrupt barriers that provide protection against infections. The genital ulcers caused by syphilis can bleed easily, and when they come into contact with oral and rectal mucosa during sex, increase the infectiousness of and susceptibility to HIV. Studies have observed that infection with syphilis was associated with subsequent HIV infection among MSM. 12, 13
Having other STDs can also indicate increased risk for becoming HIV infected. 12
What is the treatment for syphilis?
There are no home remedies or over-the-counter drugs that will cure syphilis, but syphilis is easy to cure in its early stages. A single intramuscular injection of long acting Benzathine penicillin G (2.4 million units administered intramuscularly) will cure a person who has primary, secondary or early latent syphilis. Three doses of long acting Benzathine penicillin G (2.4 million units administered intramuscularly) at weekly intervals is recommended for individuals with late latent syphilis or latent syphilis of unknown duration. Treatment will kill the syphilis bacterium and prevent further damage, but it will not repair damage already done.
Selection of the appropriate penicillin preparation is important to properly treat and cure syphilis. Combinations of some penicillin preparations (e.g., Bicillin C-R, a combination of benzathine penicillin and procaine penicillin) are not appropriate treatments for syphilis, as these combinations provide inadequate doses of penicillin. 14
Although data to support the use of alternatives to penicillin is limited, options for non-pregnant patients who are allergic to penicillin may include doxycycline, tetracycline, and for neurosyphilis, potentially ceftriaxone. These therapies should be used only in conjunction with close clinical and laboratory follow-up to ensure appropriate serological response and cure. 7
Persons who receive syphilis treatment must abstain from sexual contact with new partners until the syphilis sores are completely healed. Persons with syphilis must notify their sex partners so that they also can be tested and receive treatment if necessary.
Who should be tested for syphilis?
Any person with signs or symptoms of primary infection, secondary infection, neurologic infection, or tertiary infection should be tested for syphilis.
Providers should routinely test persons who
- are pregnant;
- are members of an at-risk subpopulation (i.e., persons in correctional facilities and MSM);
- have HIV infection;
- are taking PrEP for HIV prevention;
- have partner(s) who have tested positive for syphilis;
- are sexually active and live in areas with high syphilis morbidity.
Will syphilis recur?
Syphilis does not recur. However, having syphilis once does not protect a person from becoming infected again. Even following successful treatment, people can be reinfected. Patients with signs or symptoms that persist or recur or who have a sustained fourfold increase in nontreponemal test titer probably failed treatment or were reinfected. These patients should be retreated.
Because chancres can be hidden in the vagina, rectum, or mouth, it may not be obvious that a sex partner has syphilis. Unless a person knows that their sex partners have been tested and treated, they may be at risk of being reinfected by an untreated partner. For further details on the management of sex partners, refer to the 2015 STD Treatment Guidelines. 7
How can syphilis be prevented?
Correct and consistent use of latex condoms can reduce the risk of syphilis only when the infected area or site of potential exposure is protected. However, a syphilis sore outside of the area covered by a latex condom can still allow transmission, so caution should be exercised even when using a condom.
The surest way to avoid transmission of sexually transmitted diseases, including syphilis, is to abstain from sexual contact or to be in a long-term mutually monogamous relationship with a partner who has been tested and is known to be uninfected.
Partner-based interventions include partner notification – a critical component in preventing the spread of syphilis. Sexual partners of infected patients should be considered at risk and provided treatment per the 2015 STD Treatment Guidelines. 7
Transmission of an STD, including syphilis, cannot be prevented by washing the genitals, urinating, and/or douching after sex. Any unusual discharge, sore, or rash, particularly in the groin area, should be a signal to refrain from having sex and to see a doctor immediately.
Health care providers with STD consultation requests can contact the STD Clinical Consultation Network (STDCCN). This service is provided by the National Network of STD Clinical Prevention Training Centers and operates five days a week. STDCCN is convenient, simple, and free to health care providers and clinicians. More information is available at www.stdccn.org.
1. Centers for Disease Control and Prevention. HIV Surveillance Report, 2013; vol. 25. Published February 2015. Accessed September 23, 2015.
2. Centers for Disease Control and Prevention. Sexually Transmitted Disease Surveillance, 2013. Atlanta, GA: U.S. Department of Health and Human Services, 2014.
7. Centers for Disease Control and Prevention. Sexually Transmitted Diseases Treatment Guidelines, 2015. MMWR, 64(RR-3) (2015).
8. Available from: http://www.cdc.gov/std/stats13/minorities.htm. Last accessed December 16, 2014.
10. Centers for Disease Control and Prevention. Discordant results from reverse sequence syphilis screening--five laboratories, United States, 2006-2010. MMWR Morb Mortal Wkly Rep, 2011. 60(5): p. 133-7.
11. HIV prevention through early detection and treatment of other sexually transmitted diseases--United States. Recommendations of the Advisory Committee for HIV and STD prevention. MMWR Recomm Rep, 1998. 47(RR-12): p. 1-24.
14. Centers for Disease Control and Prevention. Inadvertent use of Bicillin C-R to treat syphilis infection--Los Angeles, California, 1999-2004. MMWR Morb Mortal Wkly Rep, 2005. 54(9): p. 217-9.
- Page last reviewed: September 24, 2015
- Page last updated: September 24, 2015
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