Treponema pallidum, subspecies pallidum.

Clinical presentation

Clinically the disease has 3 stages however about 50% of people will have no symptoms and will only be diagnosed by serological testing. (See latent syphilis below).

Primary syphilis:
  • Patients may present with a genital ulcer or chancre(s) that is usually painless
  • The ulcer tends to be non-tender and usually has a well-defined margin with an indurated base
  • May be unnoticed especially if on anal skin or on the cervix or in the mouth
  • Incubation period 10-90 days (average 3 weeks).
  • In about 30% of cases there may be multiple chancres
  • Inguinal lymph nodes are usually enlarged, rubbery and non-tender
  • Even if untreated the chancre usually spontaneously heals within a few weeks.
Secondary syphilis:
  • The patient may present with constitutional symptoms such as fever, malaise, headache and lymphadenopathy
  • The skin is involved in over 90% of cases
  • The rash is usually generalised involving the trunk but may just affect the palms and soles
  • The rash can be easily confused with drug eruptions, pityriasis rosea or guttate psoriasis
  • There may be alopecia and condylomata lata (warty growths in the ano-genital area).
  • There may also neurological signs of cranial nerve palsies, ophthalmic signs and meningitis
  • Incubation period 2-24 weeks (average 6 weeks)
  • If untreated symptoms slowly resolve over a period of weeks, but may recur.
Early Latent (<2 years) syphilis:
  • Early latent implies recent infection and therefore is treated as infectious syphilis
  • This means positive syphilis serology with no clinical symptoms or signs
  • Some people never develop symptoms and will only be diagnosed by serological tests
  • If untreated, people become asymptomatic over a period of 12-24 months after initial infection.
  • If any doubt about length of infection, treat as late latent disease.

Late latent (>2 years) syphilis:

  • After 24 months people are considered no longer infectious to sexual partners but women may still pass the infection on to the unborn foetus.
Tertiary syphilis:
  • Late symptoms/complications may develop months or years later in about one third of cases if not treated
  • Complications include skin lesions (gummas), cardiovascular or neurological disease.

See STI Atlas for images.


  • Diagnosis is by a combination of serology, history and clinical assessment.
  • If serology is negative, repeat testing after 2 weeks if clinical suspicion of syphilis.


Blood specimens are usually screened with an EIA, (although some labs still screen with TPPA or TPHA). If reactive, RPR and TPHA (or TPPA) performed as confirmatory testing.

Swab of ulcer

Diagnosis may be confirmed by direct identification of T. pallidum from an ulcer.

NAAT testing may be positive prior to seroconversion in very early cases.

EIA – Enzyme immunoassay
TPPA – Treponema pallidum Particle Agglutination Assay
TPHA – Treponema pallidum Hemaglutination Assay
RPR – Rapid plasma reagin
NAAT – Nucleic Acid Amplification Test

  • In patients with prior treated syphilis, since the EIA and TPPA tests are usually positive for life, only an RPR test is required to detect reinfection or treatment success.
  • Seek specialist advice for assistance in interpreting serology results if unsure.


Testing recommendations:

  • For men who have sex with men (MSM): at least annually, up to 4 times a year.
  • For HIV positive MSM, up to 4 times per year or at least on each occasion of CD4/viral load monitoring
  • Routine antenatal testing (repeat in late pregnancy if at risk of infection or reinfection e.g. Aboriginal women in context of current outbreak).
  • Routine immigration testing
  • A sexual contact of a person with syphilis
  • Routine sexual health check
  • Presence of any signs and symptoms of infectious syphilis.

Clinical indicators for testing

  • Genital ulcers
  • MSM with any genital symptoms or rash
  • Any rash affecting the palms of the hands or soles of the feet, or that is persistent or unexplained
  • Pyrexia of unknown origin, unexplained persistent lymphadenopathy, unexplained liver function disturbance, alopecia.

Special considerations


  • Early referral or discussion with a sexual health specialist or service is strongly recommended
  • Patients being treated for primary and secondary syphilis should have rapid plasma regain (RPR) repeated on the day treatment is commenced to provide an accurate baseline for monitoring treatment.
Principal Treatment Options
Infectious syphilis (primary, secondary, early latent) Benzathine penicillin 1.8g IMI, stat Procaine penicillin 1.5g IMI, for 10 days
Non-infectious syphilis (late latent) Benzathine penicillin 1.8g IMI, weekly for 3 weeks Procaine penicillin 1.5g IMI, for 15 days

Treatment advice

Intramuscular penicillin formulation used should be long acting, as short acting formulations (e.g. benzyl penicillin) are ineffective.

Special considerations

  • Jarisch-Herxheimer reaction is a common reaction to treatment in patients with primary and secondary syphilis. It occurs 6-12 hours after commencing treatment, and is an unpleasant reaction of varying severity with fever, headache, malaise, rigors and joint pains, and lasts for several hours. Symptoms are controlled with analgesics and rest. Patients should be alerted to the possibility of this reaction and reassured accordingly.
  • Procaine reaction is a rare reaction to procaine penicillin. It is characterised by a sensation of impending doom with hallucinations. The reaction is self-limiting and lasts about 30 minutes. The patient needs to be reassured and given general supportive measures.

Other immediate management

  • Advise no sexual contact for 7 days after treatment is administered
  • Advise no sex with partners from the last 3 months (primary syphilis) and 6 months (secondary syphilis) until the partners have been tested and treated if necessary.
  • Contact tracing
  • Provide patient with factsheet
  • Notify the state/territory health department.

Special treatment situations

Special considerations

  • Early referral or discussion with a sexual health specialist or service is strongly recommended.
Complicated  Refer those with acute neurological, ophthalmic or suspected tertiary disease to local sexual health or infectious diseases clinic
Pregnant women

Seek specialist advice. Treat as for non-pregnant according to stage. Only penicillin has been shown to be effective, so those allergic should be desensitised and treated with penicillin.
Allergy to principal treatment choice

Non-penicillin regimens have less evidence than penicillin but have shown to be effective.

Infectious Syphilis: Doxycycline 100mg PO, BD for 14 days

Non-infectious Syphilis: Doxycycline 100mg PO, BD for 28 days

HIV co-infection Discuss with sexual health specialist

Contact tracing

According to sexual history and clinical stage of infection:

  • Primary syphilis: 3 months plus duration of symptoms
  • Secondary syphilis: 6 months plus duration of symptoms
  • Late latent syphilis: long term partners only
  • Presumptively treat all sexual contacts of patients with primary or secondary syphilis regardless of serology with benzathine penicillin 1.8g IMI, stat.

See Australasian Contract Tracing Manual - Syphilis for more information.

Follow up

If confirmed STI, follow up provides an opportunity to:

  • Confirm patient adherence with treatment
  • Repeat serology to assess response to treatment - seek specialist advice
  • Confirm contact tracing has been undertaken or offer more contact tracing support.
  • Provide further sexual health education and prevention counselling.

Test of Cure (TOC)

Review all patients clinically and with repeat reactive plasma regain (RPR) testing at 3 months, then at 6 months and (if necessary) at 12 months after completing treatment.

Consider testing for HIV and other STIs at 3 month visit, if not undertaken at first presentation, or retesting post the window period.

Auditable outcomes

100% have had follow up serology tests by 6 months.

Last Updated: Thursday, 29 March 2018