Chlamydia (chlamydia trachomatis genital infection)

Last Reviewed: November 2006

What is chlamydia?

Chlamydia is a bacterial infection that is spread through sexual contact with an infected person. Chlamydia is one of the most common sexually transmitted diseases (STD); more than 50 million cases occur worldwide and approximately three million cases occur in the United States annually.

Who gets chlamydia?

Any sexually active person can be infected with chlamydia. Most often, chlamydia occurs in adolescents and young adults (ages 15-24) who have new or multiple sex partners and who do not consistently use condoms or other barrier contraception.

How is chlamydia spread?

Chlamydia is spread through sexual contact. This includes penis to vagina or penis to rectum contact. It can also be passed from the mother to her newborn during birth.

What are the symptoms of chlamydia?

Because approximately 75 percent of women and 50 percent of men have no symptoms, most people infected with chlamydia are not aware of their infections and may not seek health care. If males have symptoms, they may include urethritis (itching and/or burning on urination) and discharge from the penis in small or moderate amounts. If females have symptoms, they may include vaginal discharge and painful urination.

When and for how long is a person able to spread chlamydia?

From the time a person is infected with chlamydia, he or she can spread the disease. A person can continue to spread the infection until properly treated.

Does past infection with chlamydia make a person immune?

Past infection with chlamydia does not make a person immune to chlamydia.

What is the treatment for chlamydia?

Chlamydia is treated with antibiotics. The recommended antibiotic treatment is doxycycline taken twice a day for seven days or azrithromycin taken in one single dose. Other alternative medications may be used but are not as effective as azrithromycin and doxycycline. Persons being treated for chlamydia should not have sexual intercourse for seven days after single dose therapy (azrithromycin) or until completion of all seven days of antibiotics (doxycycline). Patients can be re-infected if their sex partners are not treated.

What happens if chlamydia goes untreated?

If a person is not treated for chlamydia, complications may occur. Women frequently develop pelvic inflammatory disease (PID). PID can cause infertility (not being able to get pregnant), chronic pelvic pain, tubal pregnancies, and the continued spread of the disease. In men, untreated chlamydia can cause urethral infection and complications such as swollen and tender testicles. Chlamydia infection during pregnancy may result in premature rupture of membranes, preterm delivery and possible tubal pregnancy in a small percent of women. In addition, chlamydia can cause conjunctival (eye) and pneumonic (lung) infection in the newborn. Persons with a chlamydia infection have an increased chance of getting other infections such as gonorrhea or HIV.

What can be done to prevent the spread of chlamydia?

  • Limit your number of sex partners
  • Use a male or female condom
  • If you think you are infected or have been exposed, avoid any sexual contact and visit a local sexually transmitted disease (STD) clinic, a hospital or your doctor. Either bring your sex partners with you when you are treated or notify them immediately so they can obtain examination and treatment.