Chlamydia and LGV: symptoms, anal infection, testing and treatment

What is chlamydia?

Chlamydia (Chlamydia trachomatis infection) is the most widespread bacterial STI. WHO estimates 128.5 million new infections worldwide in 2020. In France, Santé publique France counted about 61,100 diagnoses in community care in 2024, up 30% since 2022.

In men it affects the urethra, the anus/rectum and sometimes the throat.

What are the symptoms?

Often none. When there are some, WHO describes:

• in the penis: burning when peeing, clear discharge, testicular pain;
• in the anus: pain, discharge, bleeding.

Without symptoms you can carry and pass it on for months: that’s why it is always looked for during testing.

What about LGV?

Lymphogranuloma venereum (LGV) is caused by particular strains of chlamydia. In France it affects almost exclusively men who have sex with men. According to WHO it can cause severe inflammation:

• proctitis: anal pain, pus or blood discharge, urgent and painful need to open your bowels, alternating diarrhoea/constipation;
• genital ulcers, a single painful swollen gland in the groin (Sexosafe);
• fever, abdominal cramps.

It is sometimes mistaken for inflammatory bowel disease. If you have these symptoms, tell your doctor you have anal sex: it points to the right swabs. LGV often comes with other STIs and HIV; traumatic practices (fisting, large toys) and shared toys make transmission easier.

How are they tested?

By PCR on:

• first-catch urine;
• anal swab;
• throat swab.

If chlamydia is found in the anus, the lab can look for an LGV strain. In France, testing is free without prescription at labs for under-26s.

How are they treated?

With antibiotic tablets:

• simple chlamydia: doxycycline (usually one week) or azithromycin, according to WHO;
• LGV: doxycycline for longer (usually three weeks).

Then: no sex for 7 days after treatment and until symptoms have gone (WHO), and tell your partners.

How to prevent them?

WHO notes there is no vaccine and that condoms are the best prevention during penetration. Add:

• testing every 3 months (throat, anus, urine) with several partners;
• individual gloves and lube for fisting (fisting: the risks);
• a new condom on every shared toy (sex toys and hygiene).