Syphilis — the great imitator

Syphilis is a bacterial STI caused by Treponema pallidum — historically devastating, now curable with penicillin — yet cases are rising in England, particularly among men who have sex with men and heterosexual young adults.

It progresses through distinct stages if untreated — many symptoms mimic other diseases — earning the nickname “great imitator”.

Stages of syphilis

Primary syphilis (3 to 3 weeks post-exposure)

  • painless ulcer (chancre) — genitals, anus, mouth, or other contact site
  • firm, round, clean base
  • heals in 2 to 6 weeks without treatment — infection continues

Secondary syphilis (weeks to months later)

  • widespread rash — often includes palms and soles — unusual in other rashes
  • flu-like illness, fever
  • generalised lymphadenopathy
  • patchy hair loss
  • condylomata lata — moist warty lesions
  • resolves — enters latent phase

Latent syphilis

  • no symptoms — years to decades
  • detectable on blood test only
  • still infectious in early latent period

Tertiary syphilis (rare in treated era)

  • cardiovascular — aortic aneurysm
  • neurosyphilis — dementia, tabes dorsalis, stroke-like syndome
  • gummas — destructive tissue lesions

Early detection prevents tertiary disease.

Testing

Sexual health clinic:

  • blood test — EIA screen, TPPA/TPHA confirm
  • HIV test — offered concurrently
  • swab from chancre — PCR if ulcer present

Window period: test 12 weeks after exposure if initial negative — or earlier if symptomatic.

Antenatal screening: all pregnant women — routine blood test.

Treatment

First-line: Benzathine penicillin G — intramuscular injection

  • dose schedule depends on early vs late syphilis

Penicillin allergy: desensitisation or doxycycline — specialist protocols — not simple allergy label without assessment.

Follow-up blood tests:

  • RPR/VDRL titres fall after successful treatment
  • failure or reinfection if titres rise

Partner notification — trace and treat contacts.

Neurosyphilis — urgent

Symptoms:

  • vision loss, hearing loss
  • facial weakness
  • meningitis-like illness
  • dementia, personality change
  • stroke in young person

Hospital assessment — lumbar puncture, IV penicillin.

Syphilis and HIV

Co-infection common — syphilis may progress faster with HIV — regular screening if at risk.

Prevention

  • condoms — reduce but not eliminate — chancre may be on uncovered skin
  • regular STI screens — 3-monthly if multiple partners MSM (national guidance)
  • prompt treatment and partner tracing

Syphilis is entirely curable early — the rise in cases reflects testing and behaviour, not untreatability. Painless sore or rash on palms — sexual health clinic, not ignore.

Common questions about syphilis

What are the symptoms of syphilis?
Primary — painless ulcer (chancre) at infection site 3 weeks after contact. Secondary — rash (often palms/soles), swollen glands, fever, hair loss, wart-like growths — weeks later. Then latent (no symptoms) for years. Tertiary — heart, brain, nerve damage if untreated — rare now with testing.
Is syphilis curable?
Yes — penicillin antibiotics cure the infection at all stages. Early treatment prevents progression. Late-stage organ damage already done may not fully reverse — another reason to test early.
How is syphilis tested?
Blood tests — EIA screening then confirmatory tests. Swab from ulcer if present. Repeat test 12 weeks after potential exposure if initial test negative. HIV test offered alongside — co-infection common.
How is syphilis treated on the NHS?
Benzathine penicillin intramuscular injection — dose and duration depend on stage. Azithromycin or doxycycline alternatives if penicillin allergy — specialist guidance. Follow-up blood tests confirm treatment success — titre should fall.
Can syphilis come back after treatment?
Treatment cures current infection — does not prevent reinfection. Retest if new exposure. Rising titre on follow-up blood tests suggests treatment failure or reinfection — needs reassessment.
What is congenital syphilis?
Infection passed to baby in pregnancy — miscarriage, stillbirth, or serious infant disease. Prevented by antenatal screening and treating mother early in pregnancy — UK routine screening programme.

Sources

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