Syphilis, Antibiotic Prescribing

Comments from Expert Advisory Committee

  1. Syphilis is caused by the spirochete Treponema pallidum (T. pallidum)
  2. Acquired syphilis is commonly transmitted through sexual contact, but can also be transmitted by direct vascular inoculation (IVDU, rarely transfusions) or direct cutaneous contact with infectious lesions. Vertical transmission can occur in utero or in the peripartum period leading to congenital syphilis
  3. Acquired syphilis can be divided into two phases: early and late
  4. Early syphilis is more infectious than late syphilis and is further divided into primary syphilis (chancre); secondary syphilis (systemic phase commonly presenting with a rash) and early latent (asymptomatic within 2 years of acquisition)
  5. Late syphilis can present as late latent infection (asymptomatic greater than 2 years since acquisition); gummatous syphilis; cardiovascular syphilis or neurosyphilis. Symptomatic late syphilis can present 20 to 30 years after acquisition
  6. In Ireland since the 2000’s the majority of early infectious cases of syphilis have been in men who have sex with men (MSM). Syphilis testing is indicated in all sexually active MSM presenting with an anogenital ulcer or generalised rash and should be offered to all MSM requesting STI testing or considered to be at risk of STIs.
  7. Congenital syphilis is uncommon in Ireland and preventable with antenatal screening and appropriate maternal and neonatal management. All women should be offered syphilis testing at antenatal booking
  8. The screening test for syphilis is T. pallidum EIA (enzyme immunoassay) which checks for antibodies to T. pallidum. In individuals with syphilis, this test remains positive regardless of treatment or risk of reinfection
  9. Parenteral penicillin is first line treatment. Patients with newly diagnosed syphilis should be referred to an STI clinic for further management and treatment
  10. Individuals diagnosed with syphilis should be offered testing for other STIs including HIV, Hepatitis B, chlamydia and gonorrhoea. Hepatitis C testing is recommended in MSM.
  11. Hepatitis C testing should be considered part of routine sexual health screening in the following circumstances: People who are HIV positive; Commercial sex workers; PWID; If indicated by the clinical history e.g. unexplained jaundice; When other risk factors for HCV are present, for example MSM. The full set of recommendations around HCV testing are available in the national HCV screening guidelines
  12. Syphilis is a notifiable disease. The complete list of notifiable diseases and information on the notification process is available from the HSPC

Treatment options

  • Parenteral penicillin – the dose, duration and route (IV versus IM) is determined by the clinical circumstances
  • Oral doxycycline – the dose and duration is determined by the clinical circumstances
  • Decisions around treatment should be made by a clinician with expertise and experience in managing syphilis

Useful resources

Patient information

Reviewed October 2018