Painless chancre / rash palms & soles / gumma
Screen → confirm: RPR/VDRL → FTA-ABS
Early (primary/secondary): Benzathine penicillin G 2.4 MU IM ×1
Neuro / tertiary: IV aqueous penicillin ×10–14 d
Penicillin allergy: doxycycline 100 mg BD ×14 d (early, non-pregnant); desensitize if tertiary/pregnant
Order set
- RPR/VDRL → treponemal test
- HIV test
- LP if neuro signs
- Stage clinically
Criteria
AdmitNeurosyphilis or complications
DischargeStage-appropriate penicillin, follow-up titres, partners treated
Clinical detail — differentials, red flags, pitfalls, disposition
Red flags
- Neurosyphilis
- Ocular/otic
- Congenital risk (pregnancy)
Differentials
- Other genital ulcers (HSV, chancroid)
- Rash causes
- Neuro mimics
Common mistakes
- Missing latent/neuro staging
- Not desensitising when required
Disposition & follow-up
Benzathine penicillin by stage; partner treatment; follow titres.
Discharge package
MedicationsStage-appropriate penicillin
Follow-upRPR titres at 6/12 months (expect 4-fold decline); partner treatment
LifestyleBarrier protection
Warning symptomsRash, neuro/visual symptoms
💊 Treatment detail — doses & preparation
Benzathine penicillin Gpenicillin (syphilis)
Dose2.4 MU IM once (early syphilis); weekly ×3 (late latent)
PreparationReconstitute vial; deep IM gluteal — NEVER IV (fatal)
MonitorJarisch-Herxheimer within 24 h (fever/myalgia — warn); penicillin allergy → doxycycline
Doxycyclinetetracycline
Dose100 mg BD (urethritis ×7 d, atypical CAP, tick-borne)
Preparation100 mg capsules with full glass of water, stay upright 30 min
MonitorPhotosensitivity, oesophagitis; avoid in pregnancy/children <8
📖 CDC / BASHH SyphilisReviewed July 2026