It is caused by the bacterium Treponema pallidum (T. pallidum). There are three stages: Primary, secondary, and tertiary.
In 2015, the Centers for Disease Control and Prevention (CDC) noted that 60 percent of cases affect men who have sex with men or with both men and women.
Syphilis is treatable with antibiotics, especially in the early stages. It will not go away without treatment.
Contents of this article:
Here are some key points about syphilis. More detail information is in the main article.
- Syphilis is a sexually transmitted infection (STI) that can escalate severely without treatment.
- It is spread through sexual contact with sores, known as chancres. Shared contact with surfaces like doorknobs or tables will not spread the infection.
- Early treatment with penicillin can cure it.
- Syphilis will not come back after treatment, but it can recur with further exposure to the bacteria. Having syphilis once does not prevent a person from contracting it again.
- Women can pass syphilis to their unborn child during pregnancy, with potentially disfiguring or fatal consequences.
- The infection can lie dormant for up to 30 years before returning as tertiary syphilis.
What is syphilis?
Syphilis is spread by the T. pallidum bacterium.
Syphilis is an infection by the T. pallidum bacteria that is transmitted by direct contact with a syphilitic sore on the skin, and in mucous membranes.
A sore can occur on the vagina, anus, rectum, lips, and mouth.
It is most likely to spread during oral, anal, or vaginal sexual activity. Rarely, it can be passed on through kissing.
The first sign is a painless sore on the genitals, rectum, mouth, or skin surface. Some people do not notice the sore because it doesn't hurt.
These sores resolve on their own, but the bacteria remain in the body if not treated. The bacteria can remain dormant in the body for decades before returning to damage organs, including the brain.
Causes and risk factors
Syphilis is caused when T. pallidum transfers from one person to another during sexual activity.
It can also be passed from mother to a fetus during pregnancy, or to an infant during delivery. This is called congenital syphilis.
It cannot spread through shared contact with objects like doorknobs and toilet seats.
Who is at risk?
Sexually active people are at risk of contracting syphilis.
Those most at risk include:
- those who have unprotected sex
- men who have sex with men
- those with HIV
- people with numerous sexual partners
Syphilitic sores also increase the risk of contracting HIV.
Syphilis is spread through the sores it causes, known as chancres.
Syphilis is categorized by three stages with varied symptoms associated with each stage.
However, in some cases, there can be no symptoms for several years.
Contagious stages include primary, secondary, and, occasionally, the early latent phase.
Tertiary syphilis is not contagious, but it has the most dangerous symptoms.
The symptoms of primary syphilis are one or many painless, firm, and round syphilitic sores called chancres. These appear about 3 weeks after exposure.
Chancres disappear within 3 to 6 weeks, but, without treatment, the disease may progress to the next phase.
Secondary syphilis symptoms include:
- a non-itchy rash that starts on the trunk and spreads to the entire body, including the palms of the hands and soles of the feet. It may be rough, red, or reddish-brown in color
- oral, anal, and genital wart-like sores
- muscle aches
- sore throat
- swollen lymph nodes
- patchy hair loss
- weight loss
These symptoms can resolve a few weeks after they appear, or they can return several times over a longer period.
Untreated, secondary syphilis can progress to the latent and late stages.
The latent phase can last several years. During this time the body will harbor the disease without symptoms.
After this, tertiary syphilis may develop, or the symptoms may never come back. However, the T. pallidum bacteria remain dormant in the body, and there is always a risk of recurrence.
Treatment is still recommended, even if symptoms are not present.
Late or tertiary syphilis
Tertiary syphilis can occur 10 to 30 years after onset of the infection, normally after a period of latency, where there are no symptoms.
- damage to the heart, blood vessels, liver, bones, and joints
- gummas, or soft tissue swellings that occur anywhere on the body
Organ damage means that tertiary syphilis can often be fatal.
Neurosyphilis is a condition where the bacteria has spread to the nervous system. It is often associated with latent and tertiary syphilis, but it can appear at any time after the primary stage.
It may be asymptomatic for a long time, or it can appear gradually.
- dementia or altered mental status
- abnormal gait
- numbness in the extremities
- problems with concentration
- headache or seizures
- vision problems or vision loss
Congenital syphilis is severe and frequently life-threatening. Infection can transfer from a mother to her fetus through the placenta, and also during the birth process.
Data suggests that without screening and treatment, 70 percent of women with syphilis will have an adverse outcome in pregnancy.
Adverse outcomes include early fetal death, preterm or low birth weight, neonatal deaths, and infection in infants.
Symptoms in newborns include:
- saddle nose, in which the bridge of the nose is missing
- difficulty gaining weight
- a rash of the genitals, anus, and mouth
- small blisters on the hands and feet that change to a copper-colored rash and spread to the face, which can be bumpy or flat
- watery nasal fluid
Older infants and young children may experience:
- Hutchinson teeth, or abnormal, peg-shaped teeth
- bone pain
- vision loss
- hearing loss
- joint swelling
- saber shins, a bone problem in the lower legs
- scarring of the skin around the genitals, anus, and mouth
- gray patches around the outer vagina and anus
In 2015, the WHO confirmed Cuba as the first country in the world to have fully eradicated congenital syphilis.
Tests and diagnosis
A doctor will carry out a physical examination and ask about a patient's sexual history before carrying clinical tests to confirm syphilis.
- Blood tests: These can detect a current or past infection, as antibodies to the disease will be present for many years.
- Bodily fluid: Fluid from a chancre during the primary or secondary stages can be evaluated for the disease.
- Cerebrospinal fluid: This may be collected through a spinal tap and examined to test for any impact on the nervous system.
If there is a diagnosis of syphilis, any sexual partners must be notified of and tested for the disease.
Local services are available to notify sexual partners of their potential exposure to syphilis, to enable testing and, if necessary, treatment.
Healthcare providers also recommend HIV testing.
When to get tested
Many people will not know if they have an STI. It is a good idea to talk to a doctor or request a test:
- after having unprotected sex
- if you have a new sex partner
- if you have multiple sex partners
- if a sexual partner is diagnosed with syphilis
- if you are a man who has sex with different men
- if you have symptoms of syphilis
Anyone who is worried that they might have syphilis or another STI should speak to a doctor as soon as possible. Early treatment can cure it.
Syphilis can be treated using penicillin. The dosage will depend on the stage of the disease.
Syphilis can be treated successfully in the early stages.
Early treatment with penicillin is important, as long-term exposure to the disease can lead to life-threatening consequences.
During the primary, secondary, or late stages, patients will typically receive an intramuscular injection of Benzathine penicillin G.
The treatment strategy will depend on the symptoms and when the person was exposed.
Tertiary syphilis will require multiple injections at weekly intervals.
Neurosyphilis requires intravenous penicillin every 4 hours for 2 weeks to remove the bacteremia from the central nervous system (CNS).
Curing the infection will prevent further damage to the body, and safe sexual practices can resume, but it cannot undo any damage that has already occurred.
Those with a penicillin allergy can sometimes use an alternative medication in the early stages. During pregnancy and in the tertiary stages, anyone with an allergy will be desensitized to penicillin to allow for treatment.
Following delivery, newborns who were exposed to syphilis in the womb should undergo antibiotic treatment.
Chills, fever, nausea, achy pain, and a headache may occur on the first day of treatment. This is referred to as a Jarisch-Herxheimer reaction. It does not indicate that the treatment should be stopped.
When is it safe to have sex?
Sexual contact must be avoided until:
- all treatment has been completed
- a blood test confirms that the disease has been cured
It may take several months to see blood tests for syphilis go down to an appropriate level. This would provide confirmation of adequate treatment.
Preventive measures to decrease the risk of syphilis, include:
- abstaining from sex
- long-term mutual monogamy with an uninfected partner
- condom use, although these protect only against genital sores and not those on the body
- use of a dental dam, or plastic square, during oral sex
- not sharing sex toys
- avoiding alcohol and drugs that could potentially lead to unsafe sexual practices
Having syphilis once does not mean a person is protected from it. Once it is cured, it is possible to contract it again.