Synopsis
Assess genital ulcers without relying on stereotyped appearances, start timely herpes care, stage and treat syphilis correctly, and escalate neurological or pregnancy-related risk.
- Describe ulcers by number, pain, depth, edge, base, vesicles, lymph nodes and extragenital findings, but never use appearance alone to exclude herpes, syphilis or another serious cause.
- Swab a fresh lesion for HSV-1 and HSV-2 NAAT; routine HSV antibody testing is not a substitute for lesion diagnosis and is rarely useful in a typical presentation.
- Treat a first genital-herpes episode within five days of onset or while new lesions and systemic symptoms continue, using oral aciclovir or valaciclovir and extending after review if healing is incomplete.
- Syphilis chancres are classically painless and indurated but may be multiple, painful or atypical; secondary syphilis can cause rash involving palms and soles, mucous patches and systemic symptoms.
- Investigate suspected syphilis with treponemal and quantitative non-treponemal serology plus direct lesion testing where available, accounting for an early seronegative window.
- Treat early syphilis with benzathine penicillin G 2.4 million units intramuscularly once; late latent infection requires the same dose weekly for three doses after correct staging.
- Pregnant patients with syphilis require penicillin through specialist care; doxycycline is not an acceptable pregnancy substitute and fetal assessment must not delay maternal treatment.
- Provide partner notification, full STI testing, pregnancy counselling and clear transmission advice without implying that recurrence of herpes identifies when or from whom infection was acquired.
Key red flags
Genital herpes with urinary retention, severe sacral pain, leg weakness, meningism, confusion or disseminated lesions needs urgent hospital assessment.
Visual loss, eye pain, hearing change, vertigo, cranial neuropathy or other neurological symptoms with possible syphilis requires same-day specialist care.
Pregnancy with a first genital-herpes episode, lesions near labour or newly diagnosed syphilis requires urgent obstetric and sexual-health coordination.
Fever, hypotension, rapidly progressive ulceration, necrosis or marked immunosuppression suggests complicated or alternative invasive disease.
A genital ulcer in a child or any disclosure of coercion, exploitation or assault requires immediate safeguarding and trauma-informed referral.
Investigation priorities
Confirm herpes sensitively from a fresh vesicle or ulcer and distinguish HSV-1 from HSV-2.
Management branches
A patient presents with a new genital vesicle, erosion, fissure or ulcer.
- Take a private exposure, pregnancy, systemic, neurological and safeguarding history and inspect genital and extragenital sites with consent.
- Swab a fresh lesion for HSV NAAT, obtain syphilis and HIV serology and add direct syphilis testing or bacterial samples when phenotype supports them.
- Escalate urinary retention, meningism, ocular or auditory symptoms, systemic toxicity, pregnancy risk or possible assault immediately.