Syphilis - including symptoms, treatment and prevention

Syphilis is a sexually transmitted infection caused by the bacterium Treponema pallidum.

Syphilis and congenital syphilis are notifiable conditions1

How syphilis is spread

Almost all cases are passed on through direct contact during oral, vaginal or anal sex with a person who has syphilis. Syphilis can also be passed on to babies during pregnancy, either while the baby is in the uterus or during vaginal delivery (this is called congenital syphilis). Some babies with congenital syphilis are stillborn and others may be born with severe medical issues.

Signs and symptoms of syphilis

Symptoms of syphilis vary based on the stage of infection and there may be no symptoms at all.

Primary stage

A hard, usually painless, sore (ulcer) develops at the site of infection, usually on the genitals, 3-4 weeks after infection. Untreated, the sore usually heals and goes away within 4 weeks. There is often painless swelling of lymph glands during this stage. The sore may be inside the vagina or inside of the mouth or anus, depending on how the infection was acquired. The person may not know they have the infection.

Secondary stage

The secondary stage occurs 2 to 4 months after infection and may last several weeks. The most common feature is a flat, red rash over the whole body. Syphilis is one of the few causes of this sort of rash on the palms and soles of the feet. Many other symptoms commonly occur including fever, swelling of the glands in the groin and armpits, genital rashes, hair loss and general tiredness - almost any part of the body may be involved.

Latent period

After this secondary stage a prolonged latent period frequently occurs. A latent period is a time during which there are no symptoms or obvious signs of disease. During the latent period syphilis can only be detected by a blood test.

Tertiary stage

A tertiary (third) stage may occur in up to 30% of untreated individuals after a latent period, which may be many years. In some cases, the disease may involve the brain and spinal cord (neurosyphilis), or the heart and blood vessels (cardiovascular syphilis), producing severe complications, disability and even death.

Diagnosis of syphilis

Diagnosis of syphilis can be made during the primary and secondary stages by taking a swab test from sores and/or rashes that will detect syphilis DNA (genetic material). In addition, blood tests can be collected to measure antibodies that your body produces in response to a syphilis infection. In early infection the antibody test may be negative as this test can take up to three months to become positive.

Syphilis involving the brain and spinal cord is confirmed by testing of CSF (cerebrospinal fluid: the fluid surrounding the brain and spinal cord).

Incubation period

(time between becoming infected and developing symptoms)

9 to 90 days, with an average of 3 weeks from contact to the development of a sore.

Infectious period

(time during which an infected person can infect others)

During the primary and secondary stages and possibly the first 2 years of the latent period. A person is no longer infectious 5 days after starting appropriate antibiotic treatment or until their symptoms resolve, whichever is longer.

Treatment for syphilis

Effective antibiotic treatment is available. Treatment is usually with penicillin and needs to be supervised carefully. Long-term follow-up is required, particularly for patients with tertiary stage syphilis infection. After taking penicillin to treat syphilis, some people may develop a flu like illness (fever, aches, pains and generally feeling unwell). These symptoms will go away and do not need any specific treatment.

Treatment during pregnancy may be sufficient to prevent fetal infection. Sometimes babies require an additional course of antibiotics after birth.

Prevention of syphilis

  • All sexual partners need to be contacted, tested and treated, if needed. Even if partners have no symptoms they may be able to transmit infection to other sexual partners or reinfect you.
  • People with syphilis should refrain from any sexual contact for at least 1 week after completing treatment or until the lesions of early syphilis (if they were present) are fully healed.
  • Follow-up blood tests must be done to make sure that treatment has cured the infection.
  • Testing for syphilis during pregnancy is done at the first antenatal appointment and is also recommended by the Communicable Disease Control Branch to be done again at 28 and 36 weeks for all pregnancies.
  • Testing to exclude other sexually transmitted infections is advisable.
  • Use condoms and other barrier methods to prevent getting sexually transmitted infections, including syphilis.
  • Get tested for sexually transmitted infections regularly (even if you do not have symptoms), particularly when you have new sexual partners.

Useful links

1 – In South Australia the law requires doctors and laboratories to report some infections or diseases to SA Health. These infections or diseases are commonly referred to as 'notifiable conditions'.

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