Lymphogranuloma Venereum (LGV): Symptoms, Testing, and Treatment in the UK

Lymphogranuloma venereum, commonly known as LGV, is a sexually transmitted infection (STI) caused by three specific invasive strains (L1, L2, and L3) of the bacterium Chlamydia trachomatis. While standard chlamydia typically affects the lining of the urethra or cervix, LGV strains are more aggressive, invading the lymphatic system and deep tissues.

In the UK, LGV was historically rare, but there has been a significant increase in cases over the last two decades, particularly among men who have sex with men (MSM). According to British Association for Sexual Health and HIV (BASHH) and UK Health Security Agency (UKHSA) data, a high proportion of cases involve rectal infections. If left untreated, LGV can lead to chronic inflammation and irreversible scarring.

LGV usually progresses in three distinct stages, although symptoms can overlap or be missed entirely. The symptoms vary significantly depending on whether the infection was contracted vaginally, orally, or rectally.

Stage 1: The Primary Lesion

Between 3 and 30 days after exposure, a small, painless blister or ulcer (lesion) may appear at the site of infection. Because this lesion is often hidden inside the rectum or vagina and heals quickly without treatment, most patients do not notice it.

Stage 2: Lymph Node Swelling or Proctitis

The second stage occurs weeks to months later. If the infection is in the groin area, you may notice buboes—large, painful, swollen lymph nodes in the groin. If the infection is rectal, you may experience proctitis, with symptoms including:

• Severe rectal pain and tenesmus (a constant feeling of needing to empty the bowels).
• Bloody or mucus-like rectal discharge.
• Constipation or altered bowel habits.
• Fever, chills, and muscle aches.

Stage 3: Chronic Inflammation

Without intervention, the infection can cause long-term complications such as genital oedema (severe swelling), rectal strictures (narrowing), and fistulas (abnormal connections between organs).

Diagnosing LGV requires specific laboratory tests. A standard chlamydia test will show a positive result for Chlamydia trachomatis, but it will not specify that the strain is the more dangerous LGV variety. In the UK, if you test positive for rectal chlamydia or show symptoms of LGV, the laboratory will perform a process called NAAT (nucleic acid amplification testing) and further genotyping to confirm the L-strain.

UK clinical guidelines recommend that anyone presenting with symptoms of proctitis or significant inguinal lymphadenopathy (swelling in the groin) should be tested specifically for LGV. Because this requires specialist testing, patients are often referred to a local Integrated Sexual Health Service or can discuss their concerns with an online GP for a preliminary screening and appropriate referral.

Unlike a standard chlamydia infection, which often requires only 1 to 7 days of antibiotics, LGV requires a significantly longer course to ensure the bacteria are eradicated from the lymphatic system. Following NICE and BASHH guidelines, the first-line treatment is typically:

• Doxycycline: 100mg taken twice daily for 21 days.

If doxycycline is unsuitable (for example, during pregnancy), a 21-day course of Erythromycin may be used instead. It is vital to complete the entire three-week course, even if symptoms disappear within the first few days. Failure to finish the course increases the risk of the infection returning and causing permanent tissue damage.

Discussing sexual health can feel sensitive, and many patients prefer the privacy of an online GP consultation. A UK-based online doctor can provide a safe, confidential environment to discuss your symptoms, such as rectal discharge or groin swelling. While LGV requires specialist confirmation, an online GP can help by:

• Assessing whether your symptoms align with LGV or other common STIs.
• Providing private prescriptions for necessary antibiotics if a diagnosis has been confirmed.
• Assisting with a formal referral to local NHS clinics for specialist genotyping.
• Offering advice on partner notification and symptom management while waiting for results.

Using a private online service ensures you can speak to a professional from the comfort of your home, helping you take the first step toward recovery without delay.

LGV is highly transmissible through unprotected anal or vaginal sex and the sharing of sex toys. To prevent reinfection and protect others, you should avoid all sexual contact until you and your partners have completed treatment. In the UK, sexual health clinics offer a 'partner notification' service where they can contact previous partners anonymously to advise them to get tested. This is a critical part of public health in managing LGV clusters in the UK.