Merck Manual

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Lymphogranuloma Venereum (LGV)


Sheldon R. Morris

, MD, MPH, University of California San Diego

Last full review/revision Apr 2020| Content last modified Apr 2020
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Lymphogranuloma venereum is a sexually transmitted disease caused by Chlamydia trachomatis. It causes painful, swollen lymph nodes in the groin and sometimes infection of the rectum.

  • Lymphogranuloma venereum starts as a small, often unnoticed blister that quickly heals, then causes the lymph nodes to swell and become tender.

  • Doctors suspect the infection based on symptoms and confirm it with blood tests.

  • Antibiotics, taken for 3 weeks, can cure the infection, but the lymph nodes may remain swollen.

Lymphogranuloma venereum is caused by types of Chlamydia trachomatis that are different from those that usually cause infection of the urethra (urethritis) and cervix (cervicitis).

Lymphogranuloma venereum occurs mostly in tropical and subtropical areas and is rare in the United States. However, outbreaks have been reported among men who have sex with men in Europe, North America, and Australia.

Rectal infections caused by these bacteria have become more common among people who engage in anal sex.


Symptoms of lymphogranuloma venereum begin about 3 days after infection. They occur in three stages.

In the first stage, a small, painless, fluid-filled blister develops, usually on the penis or in the vagina. Typically, the blister becomes a sore that quickly heals and is often unnoticed.

The second stage usually begins after about 2 to 4 weeks. In men, the lymph nodes in the groin on one or both sides may swell and become tender. The enlarged, tender lymph nodes (called buboes) attach to the deeper tissues and the overlying skin, which becomes inflamed. Women often have a backache or pain in the pelvis (the lowest part of the torso), and lymph nodes near the rectum and in the pelvis become swollen and painful. In both men and women, the skin over the affected lymph nodes may break down, forming a passageway (called a sinus tract) that allows pus or blood to drain out and onto the skin. People may have a fever and feel generally unwell.

In the third stage, sores heal with scarring, but sinus tracts can persist or recur. If infection lasts a long time or recurs, lymphatic vessels (which drain fluids from tissues) may be blocked, causing genital tissues to swell and sores to form on the skin.

Rectal infection may cause a bloody, pus-filled discharge from the anus. If the infection lasts a long time, it may cause scarring, which can narrow the rectum. Lymph glands in the pelvis may swell, causing pain.


  • Tests on a sample of blood

  • Tests on a sample from the sore

Lymphogranuloma venereum is suspected in people who have characteristic symptoms and who live in or have visited areas where the disease is common or who have had sexual contact with people from those areas.

The diagnosis of lymphogranuloma venereum can be confirmed by one of the following tests:

  • A blood test that identifies antibodies against Chlamydia trachomatis

  • Tests that increase the amount of the bacteria's unique genetic material so that it can be more easily identified (called nucleic acid amplification tests, or NAATs), which are done on samples from the infected sores in the groin or rectum


The following general measures can help prevent lymphogranuloma venereum (and other sexually transmitted diseases):

  • Avoidance of unsafe sex practices, such as frequently changing sex partners or having sexual intercourse with prostitutes or with partners who have other sex partners

  • Prompt diagnosis and treatment of the infection (to prevent spread to other people)

  • Identification of the sexual contacts of infected people, followed by counseling or treatment of these contacts

Not having sex (anal, vaginal, or oral) is the most reliable way to prevent sexually transmitted diseases but is often unrealistic.


  • An antibiotic

If given early in lymphogranuloma venereum, doxycycline, erythromycin, or tetracycline (which are antibiotics), taken by mouth for 3 weeks, cures the infection, but swelling may persist if lymphatic vessels are irreversibly damaged.

Doctors may use a needle or make an incision to drain buboes (swollen lymph nodes) if they are causing discomfort.

If people have had sexual contact with an infected person during the 60 days before the person's symptoms began, they should be examined and treated with a single dose of azithromycin or with doxycycline taken by mouth for 7 days regardless of whether evidence suggests that they have lymphogranuloma venereum.

After treatment appears successful, people should be checked periodically for 6 months.

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