see also:

• safe sex and reducing risk of sexual misadventures
• sexually transmitted infections (STDs/STIs)

• syphilis is a sexually transmitted infections (STDs/STIs) caused by the spirochete bacteria, Treponema pallidum
• it was relatively common until the widespread use on penicillins in the 1950's when it became rare in Western cultures but has been gradually increasing with increased general sexual promiscuity and drug use in the 1980's but massive campaigns against HIV / AIDS and advice of safe sex and reducing risk of sexual misadventures reduced its prevalence in the 1990's. Unfortunately, it is again on the rise in line with massive rises in other sexually transmitted infections (STDs/STIs) as adherence to safe sex practices are no longer widespread.
• cannot be cultivated in vitro and is too small to be seen under the light microscope, but can be detected using dark-field microscopy or direct immunofluorescence staining of fixed smears
• rapidly penetrates intact mucous membranes or microscopic dermal abrasions
• it can also be spread:
  • from mother to baby in utero (“congenital syphilis”)
  • via blood transfusions
  • from breaks in the skin contacting syphilitic open skin lesions
• incubation period from exposure to development of primary lesions 10-90 days with average of 3 weeks
• pathology is characterised by obliterative endarteritis
• repeated infections are possible

• it was rare in Western countries apart from in indigenous populations but is now rising again
• in Victoria, 19 cases of congenital syphilis have been recorded between 2017-2024 emphasising the need for antenatal testing in 1st trimester and again at 26-28wks gestation and at 36 weeks or at delivery (whichever is earlier) with positives being treated with long acting (benzathine) penicillin
  • in addition, any pregnant person presenting with signs and symptoms suggestive of a sexually transmissible infection (STI) or who has been exposed to an STI, should be tested for syphilis.

• high rate of spontaneous abortion and stillbirth
• the first 2 years of life, symptoms are similar to severe adult secondary syphilis with widespread condylomata lata and rash
• Snuffles” describes the mucopurulent rhinitis caused by involvement of the nasal mucosae
• “saddle nose” (due to destruction of the nasal septum)
• “saber shins” (due to inflammation and bowing of the tibia)
• “Clutton’s joints” (due to inflammation of the knee joints)
• “Hutchinson’s teeth” (in which the upper incisors are widely spaced and notched)
• “mulberry molars” (in which the molars have too many cusps)
• Tabes dorsalis and general paresis may develop
• 8th cranial nerve deafness and optic nerve atrophy may occur

• the initial painless primary chancre lesion on the skin at site of initial transmission
• the lesion has a punched-out base and rolled edges and is highly infectious

• develops about 4-10 weeks after the appearance of the primary lesion as the bacteria spread throughout the body and multiply
• clinical features can be diverse but usually include:
  • malaise
  • fever
  • myalgias & arthralgias
  • lymphadenopathy
  • rash:
    • generalised mainly macular rash which may involve the palms, soles, and oral mucosae
    • can be pustular, annular, or scaling
    • wet mucous patches are the most contagious
  • condylomata lata
    • painless, highly infectious gray-white lesions that develop in warm, moist sites such as genitalia/perianal areas
  • patchy alopecia often with a “moth-eaten” appearance
• immune reaction is at its peak

• resolution of features of secondary stage but patient remains seropositive
• may have recurrence of rash
• 1/3rd will develop tertiary syphilis
• remainder will remain asymptomatic
• early latent syphilis
  • 1st 2 yrs
• late latent syphilis
  • After 2yrs, no longer infectious sexually but can still be transmitted to fetus from pregnant women

• rare
• slow inflammatory damage to tissues, especially to cardiovascular system and central nervous system
• 3 categories:
  • gummatous syphilis:
    • gummas are painless rubbery granulomas which may affect any tissue but particularly, liver, bones, testes, and which break down with necrotic centres and may form ulcers
    • Treponema are rarely seen in these lesions
  • cardiovascular syphilis
    • occurs at least 10 years after primary infection
    • ascending aortic aneurysm +/- aortic valve insufficiency
  • neurosyphilis
    • various forms:
      • syphilitic meningitis
        • usually occurring within 6 months of the primary infection
        • cerebrospinal fluid (CSF): high protein, low glucose, high lymphocyte count, and positive syphilis serology
      • meningovascular syphilis
        • results in multiple infarctions and a range of neurologic features depending on areas infarcted
      • parenchymal neurosyphilis
        • Argyll-Robertson pupil:
          • a pupil that does not react to light but does constrict during accommodation
        • tabes dorsalis
          • develops as the posterior columns and dorsal roots of the spinal cord are damaged
          • wide-based gait with impaired vibration and proprioceptive sensation, areflexia
        • general paresis
          • damage to cerebral cortex causing dementia

• non-specific VDRL and RPR serology tests:
  • ~80% sensitive in primary syphilis
    • VDRL turn positive 1-2 weeks after chancre formation
  • 100% sensitive in secondary syphilis
  • 95-98% for detecting tertiary syphilis
  • false positives may be an issue if:
    • collagen vascular disease
    • pregnancy
    • intravenous drug use
    • advanced malignancy
    • tuberculosis (TB)
    • malaria
    • viral
    • rickettsial diseases
  • positive results should be confirmed by using specific treponemal tests such as:
    • T pallidum hemagglutination (TPHA)
    • Treponemal enzyme immunoassay (EIA) for immunoglobulin G (IgG) and immunoglobulin M (IgM) may be performed
    • other specific tests include:
      • T pallidum particle agglutination (TPPA)
  • testing must be performed more than once in patients diagnosed with latent syphilis in order to exclude laboratory error
• dark-field microscopy or direct immunofluorescence staining of fixed smears
  • ~90% sensitive from swabs of moist cutaneous lesions

• notifiable disease
• single dose of long acting IM penicillin - either benzathine or procaine penicillin
  • eg. 2.4 million units IM benzathine penicillin
  • this is usually adequate for infectious syphilis (primary, secondary, early-latent stages)
  • longer courses are needed for late latent and tertiary syphilis
• partner notification and management are extremely important to prevent reinfection and to prevent spread in the community
• should no longer be infectious after the penicillin dose and rash has resolved - this usually occurs quite quickly