Syphilis

Unfortunately, rates of syphilis are increasing in high income countries across the globe. In 2023, there were 6,451 cases of Syphilis < 2 years of duration in Australia, compared to 5,915 cases in 2019. This 9% increase is of concern, as a baby can contract congenital syphilis through transplacental transmission from its mother. The transmission rate is highest (60% to 90%) during untreated primary and secondary syphilis. There were 20 cases of congenital syphilis in Australia in 2023, compared to 4 in 2019, representing a concerning 400% increase.

Symptoms
- Approximately 50% of individuals with syphilis have no symptoms.
- Often called the “Great Imitator,” syphilis can mimic many other conditions.
- Consider syphilis testing in all patients with unexplained symptoms.
Primary syphilis – on average 3 weeks post infection
- The presence of one or multiple genital, anal or oral ulcers that occur at the site of entry.
Secondary syphilis – more than 6 weeks post infection
- May include fever, malaise, headache and lymphadenopathy.
- Look for a generalised rash involving the trunk however, it may just affect the palms and soles. A skin rash occurs in over 90% of cases.
Image shows secondary stage syphilis "palmar" lesions on the palms of the hand.
Treatment
- For early syphilis, the recommended treatment is Benzathine penicillin 2.4 MU (1.8 g) administered as 2 intramuscular injections, each containing 1.2 MU (0.9 g).
- For late syphilis or syphilis of unknown duration, the treatment remains the same but is administered weekly for 3 weeks.
Test of Cure
- Repeat testing at 3 months, 6 months and 12 months (if necessary) post-treatment.
- Pregnancy: Offer routine syphilis testing at the first antenatal visit. Recommend follow-up testing at 28–32 weeks, dependent on local guidelines.
How to Order Syphilis Testing
Who to Test:
- Syphilis should be excluded in all sexually active patients presenting with a rash.
Request Form Instructions:
- Complete the Clinical Labs general pathology request form, listing syphilis and any other required STIs.
- If all recommended STIs for asymptomatic screening are required (gonorrhoea, chlamydia, syphilis, HIV, Hepatitis B and Hepatitis C), write “STI Screen” in the Clinical Notes.
Specimen Details:
- If the patient presents with a genital lesion, a swab for syphilis PCR as well as serology is recommended.
- If there is a clinical suspicion of primary syphilis but serology is negative, ensure a PCR swab has been completed and repeat serology after 2 weeks following presumptive treatment.
Test Cost:
- Bulk-billed, subject to Medicare eligibility criteria.
Additional Resources:
- STI Doctor Brochure
- STI Patient Brochure