Diagnosis & Management:

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Diagnosis and management
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Syphilis
Diagnosis and management

Diagnosis

Management: Early Syphilis

Management: Late Syphilis

Syphilis in Pregnancy

Notification

Diagnosis

Primary

Definitive diagnosis involves demonstration of Treponema pallidum by darkfield microscopy in lesions from the anogenital area.  There is no merit in performing this test on oral lesions because other treponemes, microscopically indistinguishable from T. pallidum, occur in the mouth.

A presumptive diagnosis can be made if a typical ulcer is associated with a consistent history of syphilis in sex partners and/or serologic pattern before or after treatment in the patient.

Primary syphilitic chancre of the vulva.

Secondary

Typical lesions of secondary syphilis (rash, condylomata, alopecia) and a consistent serologic pattern before and/or after treatment; being a rising RPR titre before treatment (fourfold within 6 months) and a corresponding fall after treatment.  In secondary syphilis the RPR titre will usually be 1:8 or greater.

Early latent syphilis

An asymptomatic patient with positive RPR and TPHA and one of the following:

• negative serology within the previous 2 years

• fourfold increase in RPR titre on subsequent testing

• fourfold decline in RPR within 12 months after treatment

Late syphilis

Late symptomatic syphilis is suggested when a positive treponemal test (RPR may be negative) occurs in association with typical neurologic or cardiovascular signs.

Asymptomatic neurosyphilis is suggested by positive serology and a positive CSF-VDRL.  The disease is active if there are 5 or more mononuclear cells/mm³ in the CSF.

CSF examination is indicated in the following

• before treatment of any patient with a non-penicillin regimen

• for patients who do not respond adequately or relapse after therapy

• for patients with positive serology and signs of neurosyphilis

• for all HIV positive patients who have syphilis

Late latent syphilis is characterised by a positive treponemal test (TPHA or FTA-ABS) and a negative or stable low titre RPR test.  This same pattern may be due to adequately treated syphilis or a false positive treponemal test.

Management - early syphilis (less than 2 years duration)

Standard penicillin regimens have been very effective in the treatment of early syphilis.  Recently some cases of apparent treatment failure have been documented and the problem is likely to be more severe in patients with impaired immunity, eg HIV infection.

It is possible that treatment with benzathine penicillin is less effective than treatment with procaine penicillin.  To achieve significant advantages in CSF levels over benzathine penicillin, procaine penicillin dosage should exceed 2 million units daily and probenecid should be administered concurrently.

While such large dose regimens of procaine penicillin may offer small theoretical advantages over benzathine penicillin, these regimens have low acceptance among patients and medical practitioners.  For these reasons, when a procaine penicillin regimen is employed it should be preceded by an effective dose of benzathine penicillin as a safeguard against premature termination of a course of procaine penicillin.

Treatment

Preferred treatment for all patients particularly

• patients with HIV infection

• patients at high risk of acquiring HIV infection

• patients with recurrent syphilis

benzathine penicillin G 1.8 g (2.4 million units) im as  one dose followed by procaine penicillin 3 g (3 million units) im daily plus probenecid 500 mg orally 6 hourly for 10 days

For situations where compliance with the above regimen is unlikely

benzathine penicillin G 1.8 g (2.4 million units) im as one dose

For patients who are allergic to penicillin

             doxycycline 200 mg orally daily for 20 days

or 

tetracycline HCl 500 mg orally  6 hourly for 20 days

Patient education 

Warn the patient about the possibility of a Herxheimer reaction and its management.

Stress the importance of examining all contacts immediately.  The patient should not have sex until treatment is completed and sex partners have been examined (if possible).

It is undesirable for the patient (or a sex partner - as appropriate) to become pregnant until a good response to therapy has been demonstrated.

Contact tracing

All patients are to be referred for contact tracing.

Follow-up

4 weeks - clinical assessment and sex partner review.

3, 6, 12 months - clinical assessment and repeat serology.

Management - late syphilis

Treatment

Late latent syphilis standard therapy

benzathine penicillin G 1.8 g (2.4 million units) im as one dose followed by procaine penicillin 3 g (3 million units) im daily plus probenecid 500 mg orally 6 hourly  for 20 days

or

benzathine penicillin G 1.8 g (2.4 million units) im weekly for three weeks

For patients allergic to penicillin

doxycycline 200 mg orally daily for 30 days

or

tetracycline HCl 500 mg orally 6 hourly for 30 days

Symptomatic late syphilis requires hospitalisation and treatment under consultant supervision.

 Patient education 

The degree of certainty of the diagnosis, and uncertainty (but generally be optimistic) of the prognosis should be discussed with the patient.

Contact tracing

Late syphilis is essentially non-communicable and contact tracing is not indicated.

Follow-up

Repeat serology 3, 6, 12, 24 months after treatment.  If CSF has been examined repeat at 3 monthly intervals until the cell count returns to normal.

Syphilis in pregnancy

If congenital syphilis is suspected a specialist should be consulted.

All women should have an RPR in the first trimester; women at high-risk, eg Aboriginal women, should have a further test in the third trimester.

Women with a positive test should be evaluated rapidly - history, examination, testing of contacts and if unresolved a further RPR (2 weeks after the first test).

If active syphilis cannot be reasonably excluded by this process the patient should be treated for early syphilis, as a safeguard against foetal infection.

benzathine penicillin G 1.8 g (2.4 million units) im as one dose (ADEC A)

For patients allergic to penicillin

erythromycin 500 mg orally 6 hourly for 15 days  (ADEC A)

If the mother is treated with penicillin more than 4 weeks before delivery risk to the infant is minimal and follow-up of the infant involves clinical examination at birth, serology at birth and thereafter 3 monthly until the RPR is negative.

If maternal treatment was inadequate, unknown, with drugs other than penicillin, was completed less than 4 weeks before delivery, or if adequate follow-up of the infant cannot be assured, the infant should be treated at birth and have repeat serology 3 monthly until the RPR becomes negative.  The CSF should be examined before treatment if there is a substantial risk of congenital syphilis.

For asymptomatic infants with normal CSF and for whom follow-up cannot be guaranteed

benzathine penicillin G 50,000 units/kg im as onedose

For other infants 

aqueous procaine penicillin G 50,000 units/kg im daily for 10 days

or 

aqueous crystalline penicillin G 50,000 units/kg iv 12 hourly for 10 days.

Notification

Syphilis is a notifiable infection in South Australia.

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