Chlamydia is a disease caused by the bacteria Chlamydia trachomatis. It is most commonly sexually transmitted.

Chlamydia infection is the most common sexually transmitted disease in the United States. Sexually active individuals and individuals with multiple partners are at highest risk.

As many as 1 in 4 men with chlamydia have no symptoms. In men, chlamydia may produce symptoms similar to gonorrhea. Symptoms may include:

• Burning sensation during urination
• Discharge from the penis or rectum
• Testicular tenderness or pain
• Rectal discharge or pain

Only about 30% of women with chlamydia have symptoms. Symptoms that may occur in women include:

• Burning sensation during urination
• Painful sexual intercourse
• Rectal pain or discharge
• Symptoms of PID, salpingitis, liver inflammation similar to hepatitis
• Vaginal discharge

See also: Chlamydia (female)

The diagnosis of chlamydia infection involves sampling of the urethral discharge in males or cervical secretions in females. If an individual engages in anal sexual contact, samples from the rectum may also be needed. The sample is sent for a fluorescent or monoclonal antibody test, DNA probe test or cell culture. Some of these tests may also be performed on urine samples.

The mainstay of therapy for chlamydia includes appropriate antibiotic treatment -- these include: tetracyclines, azithromycin or erythromycin.

You can get chlamydia with gonorrhea or syphilis, so if you have one sexually transmitted disease you must be screened for other sexually transmitted diseases as well. All sexual contacts should be screened for chlamydia.

Sexual partners must be treated to prevent passing the infection back and forth. There is no significant immunity following the infection and a person may become repeatedly infected.

A follow-up evaluation may be done in 4 weeks to determine if the infection has been cured.

Early antibiotic treatment is extremely successful and may prevent the development of long-term complications. Untreated infection, however, may lead to PID, scarring and ultimately infertility.

Untreated infection may lead to pelvic inflammatory disease (PID), which can cause scarring of the fallopian tubes and result in infertility. Tubal scarring also increases the likelihood of an ectopic pregnancy (tubal pregnancy).

If a women is infected with chlamydia while pregnant, the infection can cause premature labor and delivery. In addition, the infant may develop chlamydial conjunctivitis (eye infection) and chlamydial pneumonia.

Call your health care provider if you have symptoms of chlamydia.

Because many people with chlamydia may not have symptoms, sexually active adults should be screened periodically for the infection.

Safe sexual practices and consistent condom use are important ways to help reduce your chances of becoming infected with chlamydia.

A screening test for chlamydia is recommended each year for:

• Sexually active women age 25 and younger
• Women over age 25 who have new or multiple sex partners

U.S. Preventive Services Task Force. Screening for Chlamydial Infection. Rockville, MD: Agency for Healthcare Research and Quality; Update to published recommendation: Ann Intern Med. 2007;147:128-134.