Patient education: Chlamydia (Beyond the Basics)

INTRODUCTION — 

Chlamydia (pronounced klah-MID-dee-uh) is a sexually transmitted infection that can affect both men and women. There are approximately four million cases of chlamydia in the United States every year.

Chlamydia and gonorrhea (another sexually transmitted infection) can 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)".)

CHLAMYDIA CAUSES — 

Chlamydia infections are caused by a bacterium, Chlamydia trachomatis, which can infect the genital and rectal 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. Women can have rectal infection even if they do not practice anal sex, because chlamydia can also spread to the rectum from infected vaginal secretions. Insertive sex toys or objects may also spread chlamydia when shared between people. However, 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 SYMPTOMS — 

Chlamydia infections can cause mild to severe symptoms. However, most people have no symptoms at all. Because of this, people may not know they have chlamydia unless they get tested, and so it is easy to spread infection.

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)

Women and 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.

CHLAMYDIA DIAGNOSIS — 

Testing for chlamydia is usually done in a doctor or nurse's office or clinic. Tests that can be self-collected at home and sent to a laboratory for testing are increasingly available, but not all of them are accurate.

Tests can be performed on a urine sample, a swab of the vagina or cervix (in females), or a swab of the urethra (in males). Testing for rectal chlamydia can also be performed with a swab. Most clinics may provide results within one to three days, depending on the type of test performed. Some clinics use tests that can provide immediate results.

People who do a home test and receive a positive or indeterminate result should see a health care provider promptly. Even if home testing is negative, they should still see a health care provider if they have symptoms or may have been exposed because treatment may still be recommended.

CHLAMYDIA SCREENING — 

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. For older women, once-yearly testing is recommended for those who may have a higher likelihood of exposure, for instance because of a new sex partner or more than one sex partner. At least once-yearly testing for chlamydia is recommended for men who have sex with men; testing should include both urine and a rectal swab if intimate sexual contact is reported. Otherwise, testing of young sexually active men should be considered in areas of high prevalence, such as adolescent clinics, correctional facilities, and sexually transmitted infection clinics.

This is because chlamydia is common in these populations 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.

TESTING AND PREVENTION OF OTHER SEXUALLY TRANSMITTED INFECTIONS — 

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. Your vaccination record should be reviewed to make sure you have received all recommended vaccines, particularly those that prevent sexually transmitted infections (hepatitis A and B and human papillomavirus vaccines). (See "Patient education: Testing for HIV (Beyond the Basics)" and "Patient education: Gonorrhea (Beyond the Basics)".)

CHLAMYDIA COMPLICATIONS — 

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)".)

Infection during pregnancy — If you have (or think you may have) chlamydia and are pregnant or want to get pregnant, it's important to get tested and treated as soon as possible. Untreated infection can cause serious problems in pregnancy, including miscarriage and premature birth. It's also possible to pass the infection on to your baby during delivery. This can cause conjunctivitis (red, swollen eyes that may ooze liquid) that can damage the baby's eyes and affect vision over time. Newborns infected with chlamydia can also develop pneumonia (a lung infection that can cause cough and trouble breathing).

CHLAMYDIA TREATMENT — 

For most infections in nonpregnant individuals, experts recommend taking doxycycline twice daily for seven days by mouth, especially if there is a concern for rectal infection. 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.

For people who are not able to take doxycycline or who may have trouble taking antibiotics for seven days, a one-time antibiotic treatment can be taken by mouth, azithromycin. Azithromycin is also safe to take during pregnancy. It is important not to have sex for seven days after this one-time antibiotic.

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), even if they have no symptoms or recently tested negative 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 prescriptions or medications 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 (within one month) 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 approximately three months after their diagnosis, because many people (as many as 25 percent in some studies) are reinfected from untreated sexual partners.

CHLAMYDIA PREVENTION — 

The most effective way to prevent chlamydia is to avoid sexual contact. Because this is not a realistic option for most people, the following tips are recommended to reduce the risk of getting or spreading chlamydia:

●Use condoms every time you have sex. Sex toys should be thoroughly cleaned between uses.

●Do not have sex if you or your sexual partner has abnormal discharge, burning with urination, a genital rash or sore, or any other symptom that might suggest a sexually transmitted infection.

●Discuss testing for sexually transmitted infections with your doctor or nurse. Ask if you are due for chlamydia screening.

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

An antibiotic pill after sex may also lower the risk of getting chlamydia. Doctors call this "postexposure prophylaxis," or "PEP." This has only been proven effective in specific groups of people, including:

●Men who have sex with men

●Transgender women

If you are in either of these groups and at increased risk for chlamydia, PEP might be an option. Your doctor can talk to you about the medicine and help you decide. If you decide to take PEP, start taking it as soon as possible after having unprotected sex, and within three days. While PEP helps lower your risk of getting chlamydia, it is still possible to get infected. The medicine can also cause side effects, such as stomach upset. While this approach has not been proven to prevent sexually transmitted infections in other groups, including cisgender women, your doctor can provide more information on whether this might be an option for you.

WHERE TO GET MORE INFORMATION — 

Your health care 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 website (www.uptodate.com/patients). Related topics for patients, as well as selected articles written for health care 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: Sexually transmitted infections (The Basics)
Patient education: Chlamydia and gonorrhea (The Basics)
Patient education: Syphilis (The Basics)
Patient education: Anogenital warts (The Basics)
Patient education: Mycoplasma genitalium (The Basics)
Patient education: Reactive arthritis (The Basics)
Patient education: Urethritis (The Basics)
Patient education: Epididymitis and orchitis (The Basics)
Patient education: Vaginal discharge (The Basics)
Patient education: Pelvic inflammatory disease (The Basics)
Patient education: Avoiding infections in pregnancy (The Basics)
Patient education: Ectopic pregnancy (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.

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

The following organizations also provide reliable health information.

●National Library of Medicine

(medlineplus.gov/healthtopics.html)

●Centers for Disease Control and Prevention

(www.cdc.gov/std/Chlamydia/STDFact-Chlamydia.htm)

●The American Social Health Association

(www.ashasexualhealth.org)