Lymphogranuloma venereum and chancroid

01OverviewDefinition, clinical context and the essential points that orientate the chapter.

Lymphogranuloma venereum is caused by invasive C. trachomatis genovars L1, L2 and L3. The initial inoculation papule or shallow ulcer is often small, painless and already healed when the patient presents. Secondary disease produces painful inguinal or femoral lymphadenopathy, sometimes with a groove above and below the inguinal ligament, or anorectal proctocolitis. Rectal LGV can resemble inflammatory bowel disease with pain, bleeding, tenesmus, discharge, constipation, fever and systemic upset.

Chancroid is caused by Haemophilus ducreyi and remains rare in Europe. It classically causes a painful soft ulcer with a purulent base, ragged undermined edge and tender unilateral or bilateral nodes that may suppurate into buboes. Clinical distinction from herpes, syphilis, mpox, donovanosis and traumatic or malignant ulceration is unreliable. Travel and outbreak context affect probability but should guide microbiological investigation rather than serve as a diagnosis by themselves.

LGV testing begins with C. trachomatis NAAT from the affected anatomical site. A positive rectal, ulcer or node aspirate is then genotyped for LGV-associated strains through a reference pathway. Chlamydia serology is neither sufficiently specific nor sensitive for routine diagnosis. For chancroid, specialised H. ducreyi NAAT is preferred where available; culture is technically demanding and sensitivity falls with transport. Every suspected chancroid ulcer should also be tested for T. pallidum and herpes simplex virus, with HIV and broader STI screening.

Doxycycline 100 mg twice daily for 21 days is the recommended symptomatic LGV regimen because invasive tissue and lymphatic infection needs longer treatment than uncomplicated chlamydia. A fluctuant bubo can be aspirated through healthy skin for pain relief and diagnosis; incision can promote chronic sinus formation. Pregnancy requires specialist selection of a prolonged macrolide alternative and properly timed test of cure. Severe proctocolitis, obstruction, fistula or stricture warrants colorectal input.

Confirmed chancroid can be treated with ceftriaxone 250 mg intramuscularly once or azithromycin 1 g orally once. Ciprofloxacin 500 mg twice daily for three days and erythromycin 500 mg four times daily for seven days are second-line options, but ciprofloxacin is contraindicated in pregnancy and lactation and subject to current safety restrictions. HIV can slow healing and may favour a multidose course. Review at three to seven days: pain should lessen, although large ulcers and nodes heal more slowly.

Partner rules differ substantially. LGV contacts from the four weeks before symptoms, or three months before asymptomatic detection, should be examined, tested for chlamydia and given presumptive 21-day treatment. Chancroid contacts exposed during the ten days before symptom onset should be examined and treated whether or not symptoms are present. Patients should avoid sexual contact until they and partners complete therapy. Routine LGV TOC is unnecessary after recommended doxycycline, while chancroid uses clinical healing rather than routine microbiological cure testing.

Key points

LGV is invasive infection with C. trachomatis L1–L3: transient ulcer may be missed, followed by painful nodes or proctocolitis with rectal pain, bleeding, discharge and tenesmus.
Chancroid causes one or more painful soft genital ulcers with ragged undermined edges and tender regional lymphadenitis; it is rare in the UK and usually linked to travel or an outbreak.
Test LGV with chlamydia NAAT from the symptomatic rectal, ulcer or node site followed by LGV genotyping; a routine negative genital sample does not exclude rectal disease.
Diagnose chancroid with H. ducreyi NAAT or specialist culture when available, while always testing the ulcer for syphilis and herpes because clinical appearances overlap.
Treat symptomatic LGV with doxycycline 100 mg orally twice daily for 21 days; pregnancy requires a specialist alternative rather than an unqualified doxycycline course.
Treat confirmed chancroid with ceftriaxone 250 mg intramuscularly once or azithromycin 1 g orally once; use local susceptibility and specialist advice because UK disease is uncommon.
Routine LGV test of cure is unnecessary after the recommended doxycycline regimen; if required, perform it two weeks after completion. Chancroid follow-up is clinical and routine TOC is not needed.
For LGV notify contacts from four weeks before symptoms, or three months for asymptomatic infection, and give presumptive 21-day therapy; for chancroid examine and treat contacts from ten days before symptom onset.

02AetiologyUnderlying causes, associations and risk factors, with why each one matters.

Invasive chlamydia genovars

C. trachomatis L1 to L3 penetrate mucosa and spread through draining lymphatics, producing proctocolitis or nodal LGV disease.

Haemophilus ducreyi

H. ducreyi is a fastidious Gram-negative coccobacillus transmitted through sexual contact that produces necrotic painful ulcers and lymphadenitis.

Epidemiological context

LGV circulates within UK sexual networks, whereas chancroid is rare and more often linked to travel, clusters or endemic settings.

03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.

1
LGV mucosal invasion
L-genovar organisms cross the epithelial barrier, enter macrophages and travel to regional nodes rather than remaining at a superficial mucosal site.
2
Lymphatic inflammation
Granulomatous nodal inflammation causes painful enlargement, necrosis and fluctuant buboes that may rupture into chronic sinus tracts.
3
Rectal tissue injury
Invasive chlamydial inflammation causes oedema, ulceration and fibrosis, explaining pain, bleeding, tenesmus, stricture and fistula formation.
4
Chancroid ulceration
H. ducreyi induces intense neutrophilic inflammation and tissue necrosis at inoculation sites, producing soft purulent painful ulcers.

04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.

LGV proctocolitis

Rectal pain, bleeding, discharge, tenesmus, altered bowel habit and systemic symptoms after exposure is the common invasive LGV presentation.

LGV nodal syndrome

Tender unilateral inguinal or femoral nodes can enlarge into fluctuant buboes after a transient genital ulcer has disappeared.

Chancroid ulcer

A painful soft purulent ulcer with ragged undermined edges and tender suppurative nodes supports chancroid but is not diagnostic.

Complicated invasive diseaseRed flag

Severe bleeding, abdominal distension, obstruction, fistula, peritonism or sepsis requires urgent specialist and surgical assessment.

Red flags requiring action

Severe anorectal pain, bleeding, tenesmus, fever or abdominal tenderness requires urgent assessment for LGV proctocolitis and inflammatory or surgical mimics.
A fluctuant inguinal bubo can rupture and form a sinus; arrange aspiration or specialist drainage while continuing effective antibiotics.
Neurological, ocular or cardiovascular features require syphilis assessment and cannot be attributed to a local ulcer syndrome.
Pregnancy changes prolonged tetracycline and fluoroquinolone choices and requires specialist infection and maternity advice.
Persistent ulceration after therapy raises herpes, syphilis, mpox, malignancy, resistant H. ducreyi or an incorrect diagnosis.

05InvestigationsWhat to request, why it matters and how to interpret it.

Investigation order

Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.

01
Site-specific chlamydia NAAT with LGV genotypingFirst step
Why
Detect C. trachomatis at the affected rectal, ulcer or nodal site and identify invasive L genovars.
Interpretation and limitations
A positive site NAAT supports immediate therapy; reference genotyping confirms LGV, while a negative unrelated genital sample does not exclude it.
02
H. ducreyi NAAT or specialist culture
Why
Confirm chancroid from vigorously sampled ulcer-base exudate when an appropriate reference assay is available.
Interpretation and limitations
Routine laboratories may not offer testing and culture is insensitive; discuss the case early with microbiology and sexual-health specialists.
03
Syphilis and herpes ulcer tests
Why
Exclude common clinically overlapping causes of anogenital ulceration and detect coinfection.
Interpretation and limitations
Use lesion T. pallidum PCR or dark-ground microscopy where available plus serology, and HSV PCR from a fresh lesion.
04
HIV and full STI screen
Why
Identify co-infection that affects healing, transmission counselling and prevention options.
Interpretation and limitations
Interpret serology against exposure windows and repeat when an early negative result cannot exclude recent infection.
05
Proctoscopy, imaging or endoscopy
Why
Define severe proctitis, nodes, abscess, obstruction, fistula or another bowel diagnosis.
Interpretation and limitations
Choose the investigation with specialists; mucosal findings can mimic inflammatory bowel disease and histology alone may be non-specific.

06Differential diagnosisRealistic alternatives and the features that help distinguish them.

Primary syphilis

An indurated usually painless chancre and syphilis serology or lesion PCR distinguish T. pallidum from painful chancroid.

Genital herpes

Grouped vesicles and multiple painful shallow ulcers support HSV, but atypical disease requires lesion PCR rather than visual diagnosis.

Inflammatory bowel disease

Rectal LGV can closely mimic Crohn disease with bleeding, ulceration and granulomatous histology, making sexual history and rectal NAAT essential.

Ulcerated malignancy

A persistent indurated, irregular or bleeding lesion despite effective antimicrobial therapy requires biopsy and specialist cancer assessment.

Additional chapter-specific clues

Alternative ulcer infection

Painful vesicles suggest herpes, a painless indurated ulcer suggests syphilis, while persistent atypical lesions require biopsy consideration.

07ManagementImmediate care, first-line treatment, alternatives and escalation.

01DISTINGUISHInvestigate ulcer or proctitis by siteFirst stepA patient has painful genital ulceration, inguinal nodes, proctitis or an epidemiological link to LGV or chancroid.

1Record exposure sites, timing, travel, outbreak contact, pain, rectal bleeding, bowel change, systemic symptoms, pregnancy and prior antibiotics.
2Examine skin, oral and genital sites, rectum when appropriate, and inguinal nodes, looking for fluctuance, obstruction and another acute abdomen.
3Take lesion and rectal samples for chlamydia or H. ducreyi reference testing and always add syphilis, HSV, HIV and exposure-based STI tests.
4Begin specialist-directed treatment before final genotyping when the LGV syndrome is strong or disease is severe.

02LGVTreat invasive chlamydial diseaseConfirmatoryRectal or lesion chlamydia with compatible proctitis, nodes or confirmatory LGV genotype supports LGV.

1Give doxycycline 100 mg orally twice daily for 21 days and explain why the uncomplicated seven-day chlamydia course is insufficient.
2AlternativeUse a specialist macrolide alternative in pregnancy or when doxycycline cannot be used, with test of cure planned for the selected regimen.
3Aspirate fluctuant buboes through healthy skin if needed; involve colorectal specialists for severe proctitis, obstruction, fistula or stricture.
4Notify and presumptively treat partners from the correct four-week or three-month interval with a full 21-day regimen.

03CHANCROIDTreat ulcer and contactsReference testing or a specialist epidemiological assessment supports H. ducreyi infection.

1AlternativeGive ceftriaxone 250 mg intramuscularly once or azithromycin 1 g orally once, selecting a longer alternative when clinical context requires it.
2Empty fluctuant buboes by repeated aspiration when needed and avoid unnecessary incision that may promote chronic sinus formation.
3Examine and treat contacts from the ten days before symptom onset and advise abstinence until patient and partners complete therapy.
4AlternativeReview after three to seven days for pain and healing, reconsidering resistance, HIV, reinfection and alternative ulcer disease if response is poor.

Key medicines and prescribing safety4 treatments · regimens, roles and cautions

Provides prolonged intracellular and tissue therapy for invasive L-genovar chlamydial infection.

Doxycycline for LGV

Take 100 mg orally twice daily for twenty-one days for symptomatic lymphogranuloma venereum.

Review pregnancy, oesophagitis, photosensitivity and interacting cations; seek specialist advice for alternatives and ensure contacts receive equal duration.

Offers an effective single-dose regimen against H. ducreyi and can be considered during pregnancy.

Ceftriaxone for chancroid

Give 250 mg by intramuscular injection as a single dose for confirmed uncomplicated chancroid.

Check severe beta-lactam allergy, confirm the diagnosis where possible, and review healing because large ulcers or HIV-associated disease may respond slowly.

Provides an effective oral single-dose alternative with practical advantages for adherence.

Azithromycin for chancroid

Give 1 g orally as a single dose for confirmed uncomplicated chancroid.

Review QT interval, interactions, vomiting and local susceptibility; persistent disease requires specialist reassessment rather than automatic repetition.

Provides a multidose option for susceptible H. ducreyi when first-line choices are unsuitable.

Ciprofloxacin for chancroid

Give 500 mg orally twice daily for three days only when a specialist selects this second-line regimen.

Contraindicated in pregnancy and lactation; apply current fluoroquinolone restrictions and assess tendon, neurological, psychiatric and vascular risks.

08ComplicationsImportant consequences, why they occur and why they matter clinically.

Rectal stricture and fistula

Untreated LGV proctocolitis can heal with fibrosis, narrowing and abnormal tracts that require colorectal evaluation and sometimes surgery.

Chronic lymphatic damage

Nodal destruction and scarring may obstruct drainage, producing persistent genital oedema, disfigurement and recurrent local soft-tissue infection.

Bubo rupture

Suppurative nodes can perforate skin and form painful draining sinuses when aspiration and effective antimicrobial treatment are delayed.

Ongoing transmission

Unrecognised asymptomatic contacts sustain both infections, while genital ulcers increase biological susceptibility to HIV acquisition and transmission.

09Monitoring and follow-upTreatment response, safety checks and longer-term review.

Review LGV pain, rectal bleeding, bowel function and nodal size, arranging colorectal assessment for obstruction, fistula or persistent proctitis.
Routine LGV test of cure is unnecessary after completed recommended doxycycline; if required, test two weeks after therapy ends.
Review chancroid within three to seven days for symptomatic improvement and continue until ulcers and nodes have healed clinically.
Document the distinct LGV and chancroid partner lookbacks, treatments and outcomes rather than applying one generic genital-ulcer rule.
Repeat syphilis and HIV testing after the appropriate window when baseline tests were negative and exposure was recent.

10Special situationsVariants, exceptions and circumstances that change the usual approach.

LGV may lose its ulcer

The inoculation lesion is often transient, so later painful nodes or proctocolitis can occur without visible genital ulceration.

Anatomical sampling is decisive

Rectal LGV is missed by a negative urine or genital test when the symptomatic rectum was never sampled.

Buboes favour aspiration

Needle aspiration through healthy skin can relieve pain and obtain material while reducing the sinus risk associated with incision.

Chancroid is uncommon locally

Travel and outbreak information change probability, but laboratory and specialist evaluation remain necessary because ulcers overlap clinically.

Partner intervals are different

LGV uses four weeks before symptoms or three months when asymptomatic, while chancroid uses ten days before symptom onset.

11Common pitfallsFrequent interpretation and management errors.

01
Giving seven days of doxycycline for symptomatic LGV instead of the required 21-day invasive-infection course.
02
Testing urine alone in a patient whose dominant syndrome is rectal pain, bleeding and tenesmus.
03
Diagnosing chancroid from a painful ulcer without testing for syphilis and herpes.
04
Using ciprofloxacin for chancroid during pregnancy or without current fluoroquinolone safety review.
05
Applying the same partner lookback and presumptive treatment rule to both infections.
06
Calling persistent ulceration treatment failure before reconsidering HIV, reinfection, malignancy and a different pathogen.

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