Synopsis
Assess genital ulceration with consent and confidentiality, test common infectious causes without relying on appearance, recognise inflammatory, drug and malignant mimics, and coordinate treatment, partner care and safeguarding proportionately.
- Genital-ulcer morphology is not sufficiently reliable to rule an STI in or out; HSV and syphilis can be painful, painless, multiple, atypical or coexist.
- Take a private anatomy- and practice-based history, explain confidentiality and its limits, obtain consent for each examination and test and offer a chaperone.
- Swab the base of a fresh vesicle or ulcer for HSV PCR; a dry late crust gives a poorer sample and a negative result does not exclude earlier herpes.
- Request syphilis serology and repeat it when very early infection remains plausible; arrange direct lesion testing only through a service that can perform and interpret it.
- Offer HIV and exposure-site gonorrhoea and chlamydia testing and assess hepatitis vaccination or testing from history rather than ordering a genital-only panel.
- Non-sexually acquired acute genital ulcers can follow a febrile illness, especially in adolescents; the presentation does not itself establish sexual activity or abuse.
- Aphthosis, Behçet disease, Crohn disease, fixed-drug eruption, lichen sclerosus, lichen planus, pyoderma gangrenosum, trauma and malignancy are important noninfectious causes.
- First-episode genital herpes is treated promptly on clinical suspicion, commonly with oral aciclovir 400 mg three times daily for five days, extended if new lesions or healing continue.
- A persistent indurated, keratotic, bleeding or unexplained test-negative ulcer needs urgent specialist examination and biopsy rather than repeated empirical antimicrobials.
- Partner notification, abstinence until the advised point, condom limitations, vaccination, pregnancy implications and a named results route are part of treatment, not administrative extras.
Key red flags
Pregnancy near delivery, neonatal or immune vulnerability, retention, inability to drink, severe pain out of proportion, necrosis, fever or neurological signs, ocular symptoms, widespread mucosal blistering, a persistent indurated or bleeding ulcer, groin nodes, or recurrent oral and genital ulcers with eye or neurological disease requires urgent escalation.
A persistent indurated, rolled, keratotic, bleeding or enlarging ulcer and firm node requires urgent biopsy even when an initial infection test is positive.
Investigation priorities
Confirm HSV-1 or HSV-2 from an active genital lesion.
Management branches
A new genital vesicle, erosion or ulcer has no immediate surgical or skin-failure emergency.
- With consent, sample a fresh lesion base for HSV PCR and obtain syphilis serology, recording onset and whether an early repeat sample will be required.
- Offer HIV plus gonorrhoea and chlamydia testing from each exposed anatomical site and assess hepatitis, pregnancy and vaccination needs.
- Give analgesia, gentle saline or water cleansing, urination advice and a specific results, abstinence and return-symptom plan while tests are pending.