Patient information: Chlamydia

OVERVIEW

Chlamydia is the most common sexually transmitted infection in the United States [1]. Approximately four million cases of Chlamydia are estimated to occur annually in the United States, although only about one quarter of those people are tested and receive treatment. Chlamydia and gonorrhea (another sexually transmitted infection) cause similar signs and symptoms. However, chlamydia tends to have fewer symptoms and causes more significant long-term complications than gonorrhea. Infection rates are highest in adolescent women. (See "Patient information: Gonorrhea".)

CHLAMYDIA CAUSES

Chlamydia infections are caused by a bacterium known as Chlamydia trachomatis, a one-celled microorganism that is too tiny to be seen with the naked eye. This bacterium is usually transmitted during sexual intercourse. It is not possible to become infected by touching an object (eg, toilet seat).

A person can become infected when the bacterium invades mucous membranes of the mouth, throat, anus, urethra (where urine exits), or vagina. Ejaculation is not necessary to spread the infection. Risk factors for infection include multiple sexual partners, a recent new sex partner, or a history of a previous STD.

CHLAMYDIA SYMPTOMS

Infection with Chlamydia can cause mild to severe symptoms. However, some infected individuals have no symptoms at all, which allows the disease to be spread from person to person before it is detected.

Women — The most common site of infection in women is the cervix (picture 1). Only about 50 percent of women with cervical Chlamydia or cervicitis, experience symptoms, usually vaginal discharge, abnormal vaginal bleeding, or abdominal pain. Another common symptom is pain during sexual intercourse. Lower abdominal pain can be a symptom of early pelvic inflammatory disease (see below).

Cervicitis is often accompanied by infection of the female urethra, or urethritis. Urethritis can cause symptoms similar to a urinary tract infection (UTI), including a frequent urge to urinate, burning during urination, and low abdominal pain.

Men — Men with Chlamydia typically develop urethritis, which can cause pain during urination and discharge from the penis. However, up to 30 percent of men with chlamydial urethritis experience no symptoms. In a small number of cases, chlamydia can also cause infection of the epididymis, known as epididymitis, which can cause testicular pain and tenderness, swelling in the scrotum, and swelling of the epididymis itself (figure 1). Chlamydia can also cause infection of the male prostate gland, or prostatitis.

Proctitis is an infection of the anus and/or rectum. Chlamydial proctitis occurs mainly in men who have sex with men (MSM). Symptoms are rare, but may include anal or rectal pain, discharge, a persistent desire to move the bowels, and constipation.

Related disorders — Lymphogranuloma venereum (LGV) is a chlamydial infection that affects the lymph glands. It is rare in developed countries such as the United States. It is more common in men who have sex with men.

Uncommonly, people with chlamydial urethritis develop a form of arthritis, known as reactive arthritis. This is usually associated with a rash, typically develops within one month of infection, and can cause symptoms for several months. It can cause a cluster of seemingly unrelated features, including arthritis, uveitis (an inflammation of the eye), and urethritis. (See "Patient information: Reactive arthritis (formerly Reiter syndrome)".)

CHLAMYDIA DIAGNOSIS

Chlamydia can be easily identified with testing. Testing may be done because infection is suspected or as a routine screening procedure. These tests are highly sensitive and can be used on direct swabs of the cervix or urethra, or urine samples. These tests may also be used on vaginal samples, which can be collected by the patient herself (self-administered vaginal swabs). However, testing has to be done in the laboratory, and results typically take about 24 to 48 hours to be processed.

Annual testing is recommended for all sexually active women younger than 25 years old.

Other sexually transmitted infections — A person who is found to have a sexually transmitted infection (STI) or has a partner with an STI should consider testing for other infections, including HIV, gonorrhea, hepatitis B, trichomoniasis, and syphilis. (See "Patient information: Testing for HIV" and "Patient information: Hepatitis B".)

Women are advised to have an annual cervical cancer screening (Pap smear), which can detect abnormal cervical changes associated with the human papillomavirus. (See "Patient information: Cervical cancer screening".)

Men or women who use intravenous drugs or have sexual intercourse with a partner who is at risk for hepatitis C should consider testing for this infection. (See "Patient information: Hepatitis C".)

Testing is also available for herpes simplex virus, although this is not usually performed unless there are symptoms or risk factors. (See "Patient information: Genital herpes".)

CHLAMYDIA COMPLICATIONS

Chlamydia in women can lead to a serious infection known as pelvic inflammatory disease (PID). Approximately 30 percent of women with chlamydia infection will develop PID if untreated. 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). (See "Patient information: Ectopic (tubal) pregnancy".)

Infants infected during birth can develop an eye infection, which can potentially cause blindness or a lung infection. As a result, pregnant women are routinely tested for Chlamydia during pregnancy, and infants are routinely given a one-time eye treatment with an antibiotic ointment immediately after birth. This infection has nearly been eliminated as a result of testing and treatment during pregnancy.

CHLAMYDIA TREATMENT

Treatment of Chlamydia is the same for women and men. For most infections, experts favor the use of a one-time antibiotic by mouth, azithromycin (table 1). This helps to ensure that the treatment is completed and decreases the risk of treatment failure. Azithromycin is safe to take during pregnancy.

An alternate regimen is doxycycline 100 mg twice daily for 7 days. Doxycycline is not used in pregnant women because of the risk of harm to developing teeth and bones in the fetus.

Patients infected with Chlamydia are sometimes also infected with gonorrhea. For this reason, some clinicians will recommend treatment for both infections at once. (See "Patient information: Gonorrhea".)

Sexual partner treatment — Current or recent sexual partners of a person diagnosed with Chlamydia should also be treated, especially since that person may not have any symptoms. Furthermore, an untreated partner can reinfect the patient. The traditional approach has been for the patient to notify their partner that a clinic visit is necessary to test for and treat sexually transmitted infections. In contrast, some clinics have a policy of offering two prescriptions - one for the patient and one for the partner.

Sexual contact should be avoided for one week after both partners have been treated and all symptoms have resolved. It is possible to become infected with Chlamydia more than once.

Test of cure — Patients who finish the recommended treatment regimen do not need to be retested. However, a person who continues to have symptoms should be reevaluated.

CHLAMYDIA PREVENTION

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:

• Use a latex condom with every act of sexual intercourse.
• Discuss routine testing for sexually transmitted infections with a healthcare provider. Persons in a long-term, mutually monogamous relationship are at a lower risk of STIs than those with multiple sexual partners or multiple short-term relationships.
• See a healthcare provider if you have signs or symptoms of Chlamydia.
• Avoid sexual intercourse if either partner notes abnormal genital discharge, burning with urination, or a genital rash or sore.

SUMMARY

• Chlamydia is a sexually transmitted infection that can be transmitted during sex. Men do not have to ejaculate to spread the infection. It is not possible to become infected by touching an object (eg, toilet seat) (see 'Chlamydia causes' above.
• Some people with chlamydia have no symptoms. Some women have pain in the pelvis or abnormal vaginal bleeding (see 'Chlamydia symptoms' above.
• Men with Chlamydia can have pain during urination or discharge from the penis. Some men have no symptoms (see 'Men' above.
• Chlamydia can be easily identified with testing. (See 'Chlamydia diagnosis' above.)

• Untreated Chlamydia can lead to a serious complication in women, called pelvic inflammatory disease (PID). PID can lead to infertility (trouble becoming pregnant) and other serious health problems (see 'Chlamydia complications' above.
• A medication is needed to cure the infection. Anyone who is infected or who has had sex with someone who is infected should be treated. The person should not have sex until one week after treatment. (See 'Chlamydia treatment' above.)

• A latex condom can reduce the risk of Chlamydia. Testing for infections like Chlamydia is recommended before having sex with a new partner. Do not have sex if either person has discharge from the penis or vagina, pain with urination, or a genital rash or sore (see 'Chlamydia prevention' above.

WHERE TO GET MORE INFORMATION

Your healthcare provider is the best source of information for questions and concerns related to your medical problem. Because no two people are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.

This discussion will be updated as needed every four months on our web site (www.uptodate.com/patients). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.

Some of the most pertinent include:

Patient Level Information:
Patient information: Gonorrhea
Patient information: Reactive arthritis (formerly Reiter syndrome)
Patient information: Testing for HIV
Patient information: Hepatitis B
Patient information: Cervical cancer screening
Patient information: Hepatitis C
Patient information: Genital herpes
Patient information: Ectopic (tubal) pregnancy

Professional Level Information:
Cervicitis
Clinical features and diagnosis of pelvic inflammatory disease
Complications of pelvic inflammatory disease
Genital Chlamydia trachomatis infections in men
Genital Chlamydia trachomatis infections in women
Lymphogranuloma venereum
Pathogenesis of and risk factors for pelvic inflammatory disease
Pneumonia caused by Chlamydophila (Chlamydia) species in adults
Screening for Chlamydia trachomatis
Treatment of pelvic inflammatory disease

A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable.

• National Library of Medicine

       (www.nlm.nih.gov/medlineplus/healthtopics.html)

• National Institute of Allergy and Infectious Diseases

       (www3.niaid.nih.gov/topics/chlamydia/default.htm)

• American Social Health Association

       (www.ashastd.org/stdfaqs/chlamydia.html)

• Centers for Disease Control and Prevention

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

[1-4]