Sexual Health

Syphilis

Syphilis is a sexually and vertically transmissible Treponema pallidum infection with primary, secondary, latent and late multisystem manifestations; stage accurately, recognise neurological/ocular/pregnancy complications, treat through a specialist sexual-health pathway and document serological response.

In a nutshell

Syphilis is a staged, multisystem Treponema pallidum infection. Primary disease causes a chancre, secondary disease a disseminated mucocutaneous illness, latent disease is serological, and late disease can damage the cardiovascular, neurological and ocular systems. Stage it in specialist sexual-health care, treat with the appropriate penicillin regimen, notify partners, monitor RPR and protect pregnancy and organ function.

Classic presentation

A painless indurated chancre, or a widespread rash involving palms and soles with generalised lymphadenopathy; neurological, ocular, otological and pregnancy complications can occur at any stage.

Key points

A chancre is classically painless and can be extragenital or atypical; spontaneous healing does not mean cure.
Secondary syphilis is a multisystem disease: palms/soles rash, lymphadenopathy, mucous patches and condylomata lata are high-yield clues.
Early latent syphilis is within 2 years; late latent syphilis is thereafter. Stage affects treatment duration and partner notification.
Use treponemal tests to support diagnosis and a quantitative RPR to assess activity and monitor response; treponemal tests usually remain positive for life.
Benzathine penicillin G 2.4 million units IM once treats early syphilis; late latent disease needs three weekly doses; neurosyphilis needs a CNS-penetrating regimen.
Macrolides are no longer recommended because of resistance and treatment failures; pregnancy and confirmed allergy need specialist pathways.
Neurosyphilis, ocular syphilis and otosyphilis can occur at any stage and require urgent organ-specific specialist input.
The Jarisch–Herxheimer reaction is an expected treatment-related inflammatory reaction, not penicillin allergy.
Follow RPR at 3, 6 and 12 months, then six-monthly if indicated; a fourfold rise suggests reinfection or treatment failure.

First-line investigation

Specialist sexual-health assessment with treponemal serology, a quantitative baseline RPR, lesion testing when available, HIV/other STI screening and targeted neurological, ocular, otological and pregnancy assessment.

Management

Identify organ and pregnancy emergencies

Urgently involve the appropriate specialist team for visual symptoms, hearing loss, neurological deficits, cardiovascular features, pregnancy or possible congenital syphilis; do not delay treatment while waiting for a non-essential test.^1,3

Stage and document baseline serology

Perform specialist clinical assessment, treponemal testing with confirmation, quantitative RPR at treatment baseline, lesion testing when available, HIV/other STI screening and pregnancy assessment.^1,2

Explain transmission and treatment reactions

Provide partner-notification support, safer-sex counselling, clear advice about the Jarisch–Herxheimer reaction and access to specialist follow-up; coordinate a pregnancy birth plan where relevant.^1,3,4

Give stage- and site-appropriate therapy

Use benzathine penicillin for early or late latent disease according to stage; use a CNS-penetrating regimen for neurosyphilis and specialist penicillin/desensitisation pathways in pregnancy or confirmed allergy.^1,3,5

Confirm response and detect reinfection

Review clinically and repeat quantitative RPR at 3, 6 and 12 months, then six-monthly if indicated; a fourfold rise or inadequate fall requires assessment for reinfection, treatment failure and neurological disease.¹

Exam traps

A painful or multiple chancre does not exclude syphilis; the classic lesion is painless but clinical variation is common.
A negative early serology does not exclude a recent chancre; repeat testing after 2 weeks and follow the specialist pathway.
Do not use a positive treponemal test alone to diagnose active untreated disease or monitor cure; interpret it with prior treatment and quantitative RPR.
Ocular or otological disease is not safely ruled out by a negative CSF result; urgent specialist management may be needed without relying on lumbar puncture.
A Jarisch–Herxheimer reaction is not a beta-lactam allergy; do not stop treatment without senior assessment.
Do not use macrolides as a routine alternative, and do not use doxycycline as a substitute for proven fetal penicillin therapy in pregnancy.

Illustrations

Stages of syphilis over timeTimeline showing primary chancre, secondary dissemination, early and late latency, and late gummatous, cardiovascular and neurological disease, with vertical transmission shown separately.PassFinals · original

Primary syphilitic chancre on the tongueClinical photograph of a single, painless, indurated chancre on the tongue; primary chancres can occur at extragenital sites of inoculation.Centers for Disease Control and Prevention (CDC), Wikimedia Commons · Public domain

Secondary syphilis rashClinical photograph of a secondary syphilis rash involving the palms, illustrating the classic but not universal distribution.CDC/Robert Sumpter, Wikimedia Commons · Public domain

Key sources

This page is exam revision material, not medical advice, and must not be used for patient care. Always check drug doses against the BNF and current guidance. Full disclaimer.