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Syphilis is a sexually transmitted disease which is characterised by:

  • minor early illness
  • more serious late manifestations after a variable latent period

The infective agent is a spirochaete, treponema pallidum.

Syphilis burden in the UK

  • syphilis is a sexually transmitted bacterial infection caused by Treponema pallidum subspecies pallidum which can be successfully treated with antibiotics
  • the burden of syphilis in the UK has remained low since penicillin became widely available
    • however, over the past two decades the number of new diagnoses has increased and the number of cases in women more than doubled between 1999 and 2007 [1,2]

Syphilis prevalence in pregnant women remains low. A study of syphilis screening in pregnancy in England found that one-in-2800 pregnant women required treatment for syphilis in the period 2010-2011 [3].

Syphilis disease stages:

There are four stages of syphilis infection: primary, secondary, latent and tertiary (late).

  • the first two stages are symptomatic with sores, referred to as chancres, developing on the genital or mouth region in primary syphilis which lasts 4-12 weeks, and rash or more general symptoms such as fever and sore throat developing in the secondary stage which lasts 3-4 months. In some cases, these symptoms can be mild and overlooked or go unnoticed
  • latent syphilis is typically asymptomatic, although there can be a relapse of symptoms in the early latent stage, which lasts up to 2 years
    • the late latent stage, which can last a lifetime, is generally non-symptomatic
  • in one-third of cases, latent syphilis develops into the tertiary stage around 10-13 years after the initial infection. This final stage can result in severe multi-organ damage, neurosyphilis and death [4]

A single intramuscular dose of long-acting benzathine penicillin is recommended for people who have had syphilis for less than 1 year and longer courses for people with late latent syphilis [5]:

  • treatment depends on the disease stage [6]:
    • seek expert advice
      • primary, secondary, or early latent syphilis is treated with a single dose of intramuscular (IM) benzathine penicillin G 2.4 million units.
      • neurosyphilis is treated with IV penicillin G aqueous 18-24 million units daily for 14 days. An alternative regimen would be procaine penicillin G 2.4 million units IM once daily AND Probenecid 500 mg orally 4 times/day for 10-14 days
      • tertiary and latent syphilis and HIV-infected patients should be treated with weekly benzathine penicillin G 2.4 million units IM for three weeks
    • alternative therapies include doxycycline 100 mg orally (PO) twice daily for 14 days or ceftriaxone 1 to 2 gm IM or intravenously (IV) daily for 10 to 14 days or tetracycline 100 mg PO 4 times for 14 days. Azithromycin is no longer recommended due to reports of resistance.


  • Health Protection Agency. Syphilis and Lymphogranuloma venereum (LGV): resurgent sexually transmitted infections in the UK. GOV.UK. (accessed 13 Feb 2019).
  • Public Health England. Annual review of infections in UK blood, tissue and organ donors: 2016. Health Protection Report Volume 11 Number 33. 2017.
  • Townsend CL, Francis K, Peckham CS, et al. Syphilis screening in pregnancy in the United Kingdom, 2010-2011: a national surveillance study. BJOG Int J Obstet Gynaecol 2017;124:79–86. doi:10.1111/1471-0528.14053
  • Garnett GP, Aral SO, Hoyle DV, et al. The natural history of syphilis: its implications for the transmission dynamics and control of infection. Sex Transm Dis 1997;24:185-200.
  • Peeling RW et al. Syphilis. Lancet 2023; 402 (10398):336-346.
  • Tudor ME, Al Aboud AM, Leslie SW, et al. Syphilis. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from:

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