Chlamydia is a bacterial infection of the genital tract that spreads easily through sexual contact.

What is it?

  • Chlamydia is a bacterial infection of the genital tract that spreads easily through sexual contact. You may not know you have chlamydia because the signs and symptoms of pain and fluid discharge don't show up right away, if they show up at all. Many people experience no signs and symptoms.
  • Chlamydia is one of the most common sexually transmitted diseases.
  • Chlamydia isn't difficult to treat once you know you have it. If it's left untreated, however, chlamydia can lead to more-serious health problems.


Chlamydia may be difficult to detect because early-stage infections often cause few or no signs and symptoms that might alert you to see your doctor. When signs or symptoms do occur, they usually start one to three weeks after you've been exposed to chlamydia. Even when signs and symptoms do occur, they're often mild and passing, making them easy to overlook.

Signs and symptoms of chlamydia infection may include:

  • Painful urination
  • Lower abdominal pain
  • Vaginal discharge in women
  • Discharge from the penis in men
  • Painful sexual intercourse in women
  • Testicular pain in men


The bacterium Chlamydia trachomatis causes chlamydia. The condition most commonly spreads through sexual intercourse and other intimate contact between genitals and the rectal area. It's also possible for a mother to spread chlamydia to her child during delivery, causing pneumonia or a serious eye infection.

To clarify, the bacterium Chlamydia trachomatis that causes the genital infection chlamydia is different from the similarly named airborne bacterium Chlamydophila pneumoniae that causes respiratory infections, including pneumonia.


Chlamydia can be associated with other health problems, such as:

  • Human immunodeficiency virus (HIV). Women infected with chlamydia are at greater risk of acquiring HIV than are women not infected with chlamydia.
  • Other sexually transmitted infections. People who have chlamydia may also be at risk of other sexually transmitted infections, such as gonorrhea, syphilis and hepatitis. Your doctor may recommend testing for other sexually transmitted infections if you have chlamydia.
  • Pelvic inflammatory disease (PID). PID is an infection of the uterus and fallopian tubes. Although it may cause no signs or symptoms, PID can damage the fallopian tubes, ovaries and uterus, including the cervix. Untreated PID can lead to abscesses in the fallopian tubes and ovaries.
  • Chronic pelvic pain. Untreated chlamydia may lead to chronic pelvic pain in women.
  • Infertility. Scarring in the fallopian tubes caused by chlamydia infection may lead to infertility.
  • Epididymitis. A chlamydia infection can inflame the epididymis, a coiled tube located beside each testicle. Epididymitis may result in fever, scrotal pain and swelling.
  • Prostatitis. The chlamydia organism can spread to the prostate gland. Prostatitis may result in pain during or after sex, fever and chills, painful urination, and lower back pain.
  • Rectal inflammation. If you engage in anal sex, the chlamydia organism can cause rectal inflammation. This can result in rectal pain and mucus discharge.
  • Eye infections. Touching your eye with a hand moistened with infectious secretions can cause an eye infection, such as pink eye (conjunctivitis). Left untreated, the eye infection can result in blindness.
  • Infections in newborns. The chlamydia infection can pass from the vaginal canal to your child during delivery, causing pneumonia or an eye infection that can lead to blindness.


Because of the chance of other health problems if you contract chlamydia, ask your doctor how often you should have chlamydia screening tests if you're at risk. The Centers for Disease Control and Prevention recommends chlamydia screening for:

  • Sexually active women age 24 or younger. The rate of chlamydia infection is highest in this group, so a yearly screening test is recommended. Even if you've been tested in the past year, get tested when you have a new sex partner.
  • Pregnant women. You should be tested for chlamydia during your first prenatal exam. If you have a high risk of infection — from changing sex partners or from your regular partner's possible infection — get tested again later during the pregnancy.
  • Women and men at high risk. Consider frequent chlamydia screening if you have multiple sex partners or if you don't always use a condom during sex. Other markers of high risk are current infection with another sexually transmitted disease and possible exposure to any STD through an infected partner.

Screening and diagnosis of chlamydia is relatively simple. Tests include:

  • A swab. For women, your doctor may take a swab of the discharge from your cervix for culture or antigen testing for chlamydia. This can be done at the same time your doctor does a routine Pap test. For men, your doctor may insert a slim swab into the end of your penis to get a sample from the urethra. In some cases, your doctor may swab the anus to test for the presence of chlamydia.
  • A urine test. A sample of your urine analyzed in the laboratory may indicate the presence of this infection.

Treatments and drugs

Doctors treat chlamydia with prescription antibiotics such as azithromycin (Zithromax), doxycycline or erythromycin. Your doctor usually prescribes these antibiotics as pills to be swallowed. You may be asked to take your medication in a one-time dose, or you may receive a prescription medication to be taken daily or multiple times a day for five to 10 days.

In most cases, the infection resolves within one to two weeks. During that time you should abstain from sex.

Your sexual partner or partners also need treatment even though they may not have signs or symptoms. Otherwise, the infection can be passed back and forth. It's possible to be reinfected with chlamydia.


The surest way to prevent a chlamydia infection is to abstain from sexual activities. Short of that, you can:

  • Use condoms. Use a male latex condom or a female polyurethane condom during each sexual contact. Condoms used properly during every sexual encounter reduce but don't eliminate the risk of infection.
  • Limit your number of sex partners. Having multiple sex partners puts you at a high risk of contracting chlamydia and other sexually transmitted diseases.
  • Get regular screenings for sexually transmitted diseases. If you're sexually active, particularly if you have multiple partners, talk with your doctor about how often you should be screened for chlamydia and other sexually transmitted diseases.
  • Avoid douching. Women shouldn't use douche because it decreases the number of good bacteria present in the vagina, which may increase the risk of infection.