Syphilis for health professionals

Syphilis is a bacterial sexually transmissible infection (STI). It can be serious if untreated. It is a nationally notifiable disease. We monitor and report on national case numbers and epidemiological trends. We publish case definitions and national guidelines to support health professionals.

For health professionals For everyone

Disease

  • Syphilis is caused by the bacterium Treponema pallidum, subspecies pallidum.

  • Many people infected with syphilis have no symptoms.

    The clinical features of syphilis vary and can present similarly to many other conditions. The disease can progress through different stages if left untreated.

    At any stage of pregnancy (or during delivery), syphilis can spread to the unborn baby and cause congenital syphilis.

    Primary syphilis

    Symptoms usually start 10 to 90 days after infection. They are localised and typically include:

    • one or more firm ulcers, known as chancres, at the site of infection – these may not be apparent, and people may not notice any lesions. The chancres are usually painless and heal on their own within a few weeks (even if untreated)
    • enlarged lymph nodes (usually painless) in the groin area.[1] 

    Secondary syphilis

    Symptoms can start 4 to 10 weeks after primary syphilis. They can be widespread throughout the body and typically include:

    • diffuse rash, which often involves the
      • palms of the hands
      • soles of the feet
      • chest
      • back
    • white or grey lesions (condylomata lata) in the mouth or anogenital area
    • fever
    • lymphadenopathy
    • alopecia.

    Latent syphilis

    Latent syphilis is asymptomatic and can be divided into 2 categories:

    • early latent syphilis – where infection was acquired less than 2 years ago
    • late latent syphilis – where infection was acquired more than 2 years ago.[2] 

    People who have previously recovered from syphilis are more likely to have latent syphilis if reinfected.[3] [4]

    Latent syphilis can also progress to tertiary syphilis. [5] [6]

    Tertiary syphilis

    Tertiary syphilis usually starts years to decades after untreated infection. Clinical features vary depending on which body system is affected, and can include:

    • cardiovascular syphilis (aortic aneurysms and aortitis)
    • neurosyphilis (headaches, difficulty coordinating muscle movements, paralysis, numbness and dementia)
    • gummatous lesions (soft, tumour-like growths, called gummas, that can appear on the skin, bones or internal organs).[1]

    Untreated tertiary syphilis can also result in death.

    Congenital syphilis

    Congenital syphilis is serious and can result in miscarriage or stillbirth.

    In live-born infants, clinical features usually start in the first 2 to 8 weeks of life, but can also appear later in childhood.[7] They include:

    • prematurity
    • low birthweight
    • enlarged liver (hepatomegaly)
    • enlarged spleen (splenomegaly)
    • jaundice
    • dental abnormalities
    • skeletal abnormalities
    • hearing loss
    • central nervous system disease (neurosyphilis), such as hydrocephalus and cranial nerve palsies. [8] [9] [10]

    Read more about symptoms, diagnosis and treatment of syphilis.

Public health importance

  • Syphilis is a significant public health issue that can cause serious illness and even death. Although it is easily cured when diagnosed and treated early, cases have continued to rise steadily in Australia.

    Early detection is critical. Diagnostic tests are highly effective, and timely antibiotic treatment cures the infection and prevents further transmission.

    If left untreated, syphilis can lead to serious health complications. During pregnancy, untreated syphilis can cause congenital syphilis, which can result in severe health issues or death in babies.

    Each case of congenital syphilis reflects missed opportunities for early testing and treatment, and points to broader systemic barriers in healthcare access.

    The factors that contribute to the ongoing increase in syphilis cases include: 

    • limited access to healthcare, including timely testing and treatment
    • limited access to culturally appropriate sexual health services
    • social stigma
    • lack of awareness of syphilis risk among healthcare professionals and the public.[11] [12] [13] [14]

    Effectively addressing syphilis involves implementing:

    • public health actions at a population level, including supporting prevention, testing, treatment and safe sex
    • targeted and culturally appropriate efforts towards priority population groups
    • equitable access to antenatal care programs for pregnant people, including syphilis screening
    • measures to address social determinants of health contributing to the continued spread of syphilis.

    Because of this, we:

  • Syphilis cases have significantly increased across Australia over the past decade.

    The number of infectious syphilis cases in Australia has increased:

    • almost 3-fold over the past 10 years
    • almost 10-fold over the past 20 years.

    Syphilis is no longer limited to specific groups or regions, with increases seen across urban, regional and remote areas of Australia.

    Aboriginal and Torres Strait Islander people continue to be disproportionately affected, with rates 7 times higher than for non-Indigenous people in 2024.

    Rates among people who can become pregnant have also increased, coinciding with historical high notifications of congenital syphilis in recent years.

    Between 2016 and 2024:

    • 99 cases of congenital syphilis were reported
    • 33 congenital syphilis-related deaths were reported
    • congenital syphilis rates per 100,000 live births among Aboriginal and Torres Strait Islander infants were, on average, more than 16 times higher than among non‑Indigenous infants.

    For the latest information on syphilis incidence, severity, transmission and virology in Australia see:

Spread of infection

  • Person-to-person transmission most commonly occurs by direct contact with skin lesions or mucous membranes during vaginal, anal or oral sex.

    Less commonly, syphilis can be spread by:

    • non-sexual direct contact with infected lesions
    • infected blood (such as via injection drug use)
    • accidental direct inoculation (such as needle stick injury).

    Vertical transmission to babies can occur at any time during pregnancy (congenital syphilis).

  • The clinical features of primary syphilis are usually apparent from 10 to 90 days after exposure (most commonly around 21 days).

  • People are most infectious during primary, secondary and early latent syphilis.

    Generally, people are not considered infectious during late latent and tertiary syphilis.

    Vertical transmission can occur at any stage of syphilis infection.

Priority populations

  • In Australia, efforts to address syphilis are focused on:

    • people who can become pregnant
    • babies of pregnant people who have syphilis
    • Aboriginal and Torres Strait Islander people who live in outbreak regions.

    Syphilis poses a greater risk of severe illness for:

    • people who do not receive appropriate antibiotic treatment, particularly in the early stages of their infection
    • people with concurrent HIV infection
    • babies born to people with untreated syphilis during their pregnancy.

    Read more about measures people can take to protect themselves.

  • People are more likely to be exposed to syphilis in areas with ongoing community transmission.

    Those at greater risk of infection include:

    • people who have unprotected vaginal, anal or oral sex with someone infected with syphilis
    • babies of people who had untreated syphilis during their pregnancy.

    In Australia, there is continued high prevalence of syphilis in:

    • remote Aboriginal and Torres Strait Islander communities
    • non-Indigenous gay or bisexual males and other men who have sex with men in major cities.

    See what measures people can take to protect themselves.

  • Sexually transmitted infections, including syphilis, can spread within sexual networks and in settings with frequent sexual activity between different partners, such as:

    • venues that offer sex on premises
    • parties or other social events where intimate contact occurs.

    The risk is higher in areas where syphilis is circulating in the community.

    Taking steps to prevent syphilis is particularly important in these settings.

Prevention

  • There is no vaccine against syphilis.

  • Healthcare professionals can help prevent syphilis infection by:

    • encouraging regular sexual health checks
    • providing education to support people to practise safe sex
    • educating people on the symptoms of syphilis and what to do if they develop them
    • advising people to avoid sexual activity with anyone with syphilis symptoms until they have sought medical advice and testing
    • advising people who test positive to tell their sexual partners to also get tested and treated for syphilis to avoid reinfection
    • ensuring syphilis screening during pregnancy, within recommended timeframes outlined in the Australian Pregnancy Care Guidelines
    • considering the use of doxycycline post-exposure prophylaxis (Doxy-PEP), in line with the Doxy-PEP Decision Making Tool.

  • Healthcare professionals should proactively recommend screening for priority populations as outlined in the Australian STI management guidelines for use in primary care.

Diagnosis and clinical management

  • Syphilis is primarily diagnosed by:

    • serological testing through a blood test (treponemal specific and non-treponemal tests)
    • nucleic acid amplification test of lesion specimens (such as anogenital lesions or ulcers) if present.

    Other diagnosis methods include tissue diagnosis and analysis of cerebrospinal fluid. 

    Interpretation of syphilis serology is complex – past testing and treatment history, clinical assessment and specialist microbiologist advice are often needed. 

    See the Australian STI management guidelines for use in primary care for guidance on diagnosis.

    A syphilis point-of-care treponemal specific test is available in some parts of Australia. This can help identify and treat cases early, when used in combination with laboratory-based serology and treatment history information.

  • Read more about laboratory testing and access the laboratory case definition.

  • Syphilis is treated with antibiotics. Follow up with repeat testing is important to monitor whether the patient is responding to treatment.

    Pregnant people who test positive for syphilis should be encouraged to seek urgent specialist advice and get treated during pregnancy to minimise the risk of vertical transmission.

    Sexual partners of people infected with syphilis should also be tested and treated if they test positive.

    Successful treatment of previous syphilis infection does not protect against reinfection.[4]

    Read more about the clinical management of syphilis.

Notification and reporting

Public health response

  • The CDNA national guidelines for public health units inform the public health response to syphilis, including how syphilis cases, contacts and outbreaks are managed.

  • Public health units work with treating clinicians to investigate syphilis cases, with a focus on appropriate antibiotic treatment and contact tracing.

    People with syphilis should be provided information about how to prevent spread to others including advice to:

    • not have any sexual contact for 7 days after treatment is completed or until symptoms have resolved (whichever is longer)
    • not have sexual contact with current or previous sexual partners until all partners:
      • have been tested and treated, if necessary (see management of contacts)
      • are no longer infectious (as previous infection and recovery from syphilis does not protect against reinfection)
    • get regular sexual health checks.

    Physical isolation of people infected with syphilis is not required.

    See the CDNA national guidelines for public health units for detailed guidance on how states and territories respond to syphilis cases.

  • Public health units work with primary health and sexual health clinicians to undertake contact tracing to:

    • identify all potential contacts who have been exposed to syphilis, including babies of pregnant people infected with syphilis
    • clinically assess and test contacts for infection
    • provide advice and public health education
    • provide antibiotic treatment, where appropriate.

    Public health messaging focuses on advising contacts to abstain from sexual activity for 7 days after completing antibiotic treatment or until they test negative to syphilis (whichever is earlier).

    See the Australian Contact Tracing Guidelines for detailed guidance on contact tracing.

    Online tools that can assist with contact tracing include:

    See the CDNA national guidelines for public health units for detailed guidance on how states and territories manage contacts for syphilis cases.

  • How public health agencies respond to syphilis cases and outbreaks depends on:

    • state or territory legislation
    • local reporting requirements
    • the nature of the cases or outbreak
    • available resources.

    Syphilis preparedness and response initiatives involve:

    • engaging early and establishing trust with local community and health services, including Aboriginal and Torres Strait Islander community-controlled health organisations
    • consulting with communities to co-design syphilis control strategies and programs.

    Additional control measures used during outbreaks may include:

    • providing tailored public health education and messaging to the community and health staff about syphilis, including its symptoms and how to prevent spread
    • providing access to appropriate testing and treatment services.

    The CDNA national guidelines for public health units provides more information on how to respond to syphilis outbreaks.

  • High-risk settings and certain population groups might require extra infection and control actions to reduce syphilis infection.

    Read more about prevention and outbreak response.

    See the CDNA national guidelines for public health units for more detailed guidance.

Resources

References

  • 1 KG Ghanem, S Ram et al., ‘The modern epidemic of syphilis’, The New England Journal of Medicine, 2020, 382(9):845–854, doi:10.1056/NEJMra1901593.
  • 2 World Health Organization, ‘WHO guidelines for the treatment of Treponema pallidum (syphilis)’, 1 January 2016, accessed 17 June 2025.
  • 3 CM Marra, CL Maxwell et al., ‘Previous syphilis alters the course of subsequent episodes of syphilis’, Clinical Infectious Diseases, 2020, 71(5):1243–1247, doi:10.1093/cid/ciz943.
  • 4 J Marshall, E Kerr et al., ‘Syphilis reinfection in New South Wales, 2014–2021’, International Journal of Infectious Diseases, 2023, 130(2): S35, doi:10.1016/j.ijid.2023.04.081.
  • 5 EW Hook, ‘Syphilis’, The Lancet, 2017, 389(10078):1550–1557, doi:10.1016/S0140-6736(16)32411-4.
  • 6 ME Tudor, AM AI Aboud, SW Leslie, W Gossman, Syphilis, StatPearls Publishing, Florida, 2025.
  • 7 DD Villarreal, KA Lewis et al., ‘Patterns of congenital syphilis in a large public hospital: Maternal risk factors and infant outcomes’, Sexually Transmitted Diseases, 2025, 52(7):395–401, doi:10.1097/OLQ.0000000000002162.
  • 8 J Carrier and V Haughton, ‘A challenging case for NICU clinicians’, Neonatal Network, 2019, 38(3):170–177, doi:10.1891/0730-0832.38.3.170.
  • 9 D Sankaran, E Partridge et al., ‘Congenital syphilis: An illustrative review’, Children (Basel), 2023, 10(8):1310, doi:10.3390/children10081310.
  • 10 AF Braga Rocha, MA Leite Araujo et al., ‘Complications, clinical manifestations of congenital syphilis, and aspects related to its prevention: an integrative review’, Revista Brasileira de Enfermagem, 2021, 74(4):1–8, doi:10.1590/0034-7167-2019-0318.
  • 11 B Hengel, H McManus et al., ‘Notification rates for syphilis in women of reproductive age and congenital syphilis in Australia, 2011–2021: A retrospective cohort analysis of national notification data’, The Medical Journal of Australia, 2024, 221(4):201–208, doi:10.5694/mja2.52388.
  • 12 L East, D Jackson et al., ‘Stigma and stereotypes: Women and sexually transmitted infections’, Collegian, 2012, 19(1):15–21, doi:10.1016/j.colegn.2011.10.001.
  • 13 T Rahman, FYS Kiong et al., ‘Increasing awareness of sexually transmitted infections (STI) testing and addressing stigma may improve STI testing in Aboriginal and Torres Strait Islander youth: Evidence from the Next Generation Youth Wellbeing Study’, Australian and New Zealand Journal of Public Health, 2024, 48(6):100203, doi:10.1016/j.anzjph.2024.100203.
  • 14 S Bond and MY Chen, ‘The resurgence of congenital syphilis in Australia: Novel approaches and sustained, effective public health efforts are required’, The Medical Journal of Australia, 2024, 221(4):195–196, doi:10.5694/mja2.52393.

We are adding new content to this website and expanding these pages, including a suite of disease-related information. In the meantime, information about diseases in Australia is available on the Department of Health, Disability and Ageing’s website. 

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