Official reprint from UpToDate®
www.uptodate.com ©2017 UpToDate, Inc. and/or its affiliates. All Rights Reserved.

Patient education: Chlamydia (Beyond the Basics)

Jeanne Marrazzo, MD, MPH, FACP, FIDSA
Section Editor
Noreen A Hynes, MD, MPH, DTM&H
Deputy Editor
Allyson Bloom, MD
0 Find synonyms

Find synonyms Find exact match



Chlamydia (pronounced klah-MID-dee-uh) is the most common sexually transmitted infection in the United States [1]. There are about four million cases of chlamydia in the United States every year.

Chlamydia and gonorrhea (another sexually transmitted infection) cause similar signs and symptoms, including discharge from the penis or vagina and pain with urination. However, chlamydia usually causes no symptoms. In addition, chlamydia can cause serious long-term complications in women who are not treated. Fortunately, chlamydia is curable with antibiotic treatment. (See "Patient education: Gonorrhea (Beyond the Basics)".)

More detailed information about chlamydia is available separately. (See "Clinical manifestations and diagnosis of Chlamydia trachomatis infections" and "Treatment of Chlamydia trachomatis infection".)


Chlamydia infections are caused by a bacterium, Chlamydia trachomatis, which can infect the genital tract of women (figure 1) and men (figure 2). The infection is spread during intimate sexual contact. A man does not have to ejaculate to spread the infection. It is not possible to become infected with chlamydia by touching an object like a toilet seat.

Your risk of getting chlamydia is greater if you have a new sexual partner, more than one sexual partner, or if you have had chlamydia before and have sex with a partner who wasn’t treated for this infection.


Chlamydia infections can cause mild to severe symptoms. However, most people have no symptoms at all. This means that it is easy to spread the infection without ever knowing you are infected.

Women — Up to 90 percent of women with chlamydia have no symptoms at all. Of those who do, the most common symptoms include:

Vaginal discharge

Abnormal vaginal bleeding

Abdominal pain

Pain during sex

Burning or pain with urination

Men — Up to 70 percent of men with chlamydia have no symptoms at all. The most common symptoms of chlamydia in men include:

Burning or pain with urination

Discharge from the penis

Pain or tenderness of the testicles

Swelling in the scrotum (figure 2)

Men who have sex with men can develop a chlamydia infection in the rectum or anus.

Related disorders — Uncommonly, people with chlamydia develop a form of arthritis, called reactive arthritis. It can cause a cluster of seemingly unrelated features, including joint pain (arthritis) and uveitis (an inflammation of the inner part of the eye). (See "Patient education: Reactive arthritis (Beyond the Basics)".)

Chlamydia can also cause an inflammation of the conjunctiva (conjunctivitis). This can be caused by exposure to genital fluids, such as semen or vaginal discharge, from a person infected with the bacteria.


Testing for chlamydia is done in a doctor or nurse's office with a sample of urine or with a swab of fluid from the vagina or from the cervix (in women) or urethra (in men). Results are usually available within 24 hours.


Once-yearly testing for chlamydia is recommended for all sexually active women who are younger than 25 years old, even in the absence of symptoms. This is because chlamydia is common in this age group and infection usually does not cause symptoms. Treating this infection can prevent some of the major problems it causes, especially infection of the female reproductive organs, as described below.


If you or your sexual partner are diagnosed with a sexually transmitted infection like chlamydia, you should have testing for other infections, including HIV, gonorrhea, trichomoniasis, and syphilis. (See "Patient education: Testing for HIV (Beyond the Basics)" and "Patient education: Gonorrhea (Beyond the Basics)".)


Chlamydia in women can lead to a serious infection called pelvic inflammatory disease (PID). If chlamydia is not treated, up to 30 percent of women may develop PID. PID can cause scarring of the fallopian tubes, which can lead to infertility and an increased risk of ectopic pregnancy (a pregnancy that develops in the fallopian tube rather than the uterus) or chronic pelvic pain. (See "Patient education: Ectopic (tubal) pregnancy (Beyond the Basics)".)


Treatment of chlamydia is the same for women and men. For most infections, experts recommend a one-time antibiotic treatment that is taken by mouth, azithromycin. Azithromycin is safe to take during pregnancy.

Anyone who is allergic to azithromycin (or erythromycin) can take another antibiotic, doxycycline, but this must be taken twice daily for 7 days. It is important not to have sex during this treatment. Doxycycline is not used in pregnant women because of the risk of harm to developing teeth and bones in the fetus.

Some people who are infected with chlamydia may also be infected with gonorrhea. Thus, testing for gonorrhea is sometimes done at the same time as chlamydia testing. If the patient has both infections, additional treatment for gonorrhea will be needed. (See "Patient education: Gonorrhea (Beyond the Basics)".)

Sexual partner treatment — Treatment is important for you and anyone you have had sex with recently (the last 60 days, or the last person you had sex with), whether or not he or she has symptoms or has a negative test for chlamydia. This is because not all infections cause symptoms, and because the test might not detect a recent infection, which could have been the source of your infection. Your doctor or nurse might ask you to tell your sexual partner(s) to be treated. In some cases, your doctor or nurse may give you a prescription for both you and your partner.

You should not have sex until one week passes after both you and your partner have completed treatment. It is possible to be infected with chlamydia more than once, and the most common reason for this is failure to treat sexual partners.

If you take the recommended treatment, you will not need to be tested in the short term (1 to 2 months) to make sure that the chlamydia is gone unless you continue to have symptoms. If symptoms do recur or occur for the first time after you are treated you should see your doctor or nurse again.

However, anyone with chlamydia should have another test for chlamydia three to six months after their diagnosis, because many people (as many as 25 percent in some studies) are re-infected from untreated sexual partners.


The most effective way to prevent chlamydia is to avoid sexual intercourse. Because this is not practical for most people, the following tips are recommended:

Men should use a latex condom every time they have sex.

Discuss testing for sexually transmitted infections with your doctor or nurse. If you are a woman under 25 years old, ask if you are due for your annual chlamydia screening.

See your doctor or nurse if you have any symptoms of chlamydia or another infection.

Do not have sex if you or your sexual partner has abnormal discharge, burning with urination, or a genital rash or sore.


Your healthcare provider is the best source of information for questions and concerns related to your medical problem.

This article will be updated as needed on our web site (www.uptodate.com/patients). Related topics for patients, as well as selected articles written for healthcare professionals, are also available. Some of the most relevant are listed below.

Patient level information — UpToDate offers two types of patient education materials.

The Basics — The Basics patient education pieces answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials.

Patient education: Avoiding infections in pregnancy (The Basics)
Patient education: Chlamydia and gonorrhea (The Basics)
Patient education: Ectopic pregnancy (The Basics)
Patient education: Anogenital warts (The Basics)
Patient education: Pelvic inflammatory disease (The Basics)
Patient education: Reactive arthritis (The Basics)
Patient education: Screening for sexually transmitted infections (The Basics)
Patient education: Syphilis (The Basics)
Patient education: Vaginal discharge in adults (The Basics)
Patient education: Epididymitis (The Basics)
Patient education: Urethritis (The Basics)
Patient education: Newborn conjunctivitis (The Basics)
Patient education: Bartholin's gland cyst (The Basics)

Beyond the Basics — Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are best for patients who want in-depth information and are comfortable with some medical jargon.

Patient education: Gonorrhea (Beyond the Basics)
Patient education: Reactive arthritis (Beyond the Basics)
Patient education: Testing for HIV (Beyond the Basics)
Patient education: Hepatitis B (Beyond the Basics)
Patient education: Ectopic (tubal) pregnancy (Beyond the Basics)

Professional level information — Professional level articles are designed to keep doctors and other health professionals up-to-date on the latest medical findings. These articles are thorough, long, and complex, and they contain multiple references to the research on which they are based. Professional level articles are best for people who are comfortable with a lot of medical terminology and who want to read the same materials their doctors are reading.

Acute cervicitis
Pelvic inflammatory disease: Clinical manifestations and diagnosis
Long-term complications of pelvic inflammatory disease
Lymphogranuloma venereum
Pelvic inflammatory disease: Pathogenesis, microbiology, and risk factors
Pneumonia caused by Chlamydia pneumoniae in adults
Screening for sexually transmitted infections
Pelvic inflammatory disease: Treatment
Clinical manifestations and diagnosis of Chlamydia trachomatis infections
Treatment of Chlamydia trachomatis infection

The following organizations also provide reliable health information.

National Library of Medicine


Centers for Disease Control and Prevention


The American Social Health Association


Literature review current through: Nov 2017. | This topic last updated: Sun Oct 08 00:00:00 GMT 2017.
The content on the UpToDate website is not intended nor recommended as a substitute for medical advice, diagnosis, or treatment. Always seek the advice of your own physician or other qualified health care professional regarding any medical questions or conditions. The use of this website is governed by the UpToDate Terms of Use ©2017 UpToDate, Inc.

All topics are updated as new information becomes available. Our peer review process typically takes one to six weeks depending on the issue.