What Is Chlamydia? Symptoms, Causes, Diagnosis, Treatment, and Prevention

Chlamydia is one of the most common sexually transmitted diseases (STDs) in the United States. It’s especially common in young adults, for reasons that have to do with both the biology of young bodies and the lifestyle choices made by many young people, such as having sex with many different partners.

While chlamydia can be easily and quickly treated, untreated chlamydia can — and often does — cause infertility in women. Symptoms of chlamydia can be mild or nonexistent, which means it’s important to get screened for it if you fit the recommended screening criteria.

“The signs of chlamydia are so subtle that women often don’t realize they have an infection,” says Jill Rabin, MD, the cochief of ambulatory care for women's health programs and prenatal care assistance services for Northwell Health in New Hyde Park, New York. And, she emphasizes, “Usually the disease has no symptoms” in women.

When symptoms occur, they tend to develop one to three weeks after exposure to chlamydia.

Chlamydia Symptoms in Women

In cases of chlamydia where symptoms occur, women may have one or more of the following symptoms:

• Pain or a burning sensation while urinating
• Abnormal vaginal discharge that may be watery or milky
• Painful discharge or bleeding from the anus
• Inflamed eyelids (from contact with genital secretions)

Advanced chlamydia may cause additional symptoms in women. The following symptoms indicate that chlamydia infection has spread to the fallopian tubes:

• Pain during sex
• Lower abdominal pain
• Bleeding between menstrual periods
• Nausea or fever

Chlamydia Symptoms in Men

Up to half of all men with chlamydia experience no symptoms. When men do have signs or symptoms, they may be minor and may include one or more of the following:

• Pain or burning while urinating
• An abnormal discharge from the penis, which may be pus (a thick yellowish-white fluid) or a watery or milky fluid
• Painful discharge or bleeding from the anus
• Inflamed eyelids (from contact with genital secretions)
• Painful or swollen testicles

Learn More About Symptoms of Chlamydia

There are a few different types of diagnostic tests for chlamydia. The newest type, known as nucleic acid amplification tests (NAATs), can easily be performed on a swab of your vagina or a urine sample. Vaginal swabs are the preferred method to test for genital chlamydia in women, while urine samples are preferred for men.

Most labs aren’t approved by the U.S. Food and Drug Administration (FDA) to test rectal or throat swabs for chlamydia, but a doctor may still order these tests.

Who Should Get Tested for Chlamydia?

Pregnant women should be screened for chlamydia according to the above guidelines, with a second test during the third trimester of pregnancy. If a pregnant woman tests positive for chlamydia, she should be tested again three to four weeks after treatment to ensure that it was effective, plus once more within three months.

Men who have sex with men should also get screened for chlamydia yearly, with any potential areas of contact — urethra, rectum, or throat — included in these tests, regardless of whether condoms were used. Men in this group with multiple sex partners, or whose partner has multiple partners, should get tested every three to six months instead.

The CDC recommends screening all men for chlamydia at certain high-risk facilities, such as prisons and jails and STD clinics.

People with HIV should be tested for chlamydia at their first HIV evaluation, and at least once a year after that if they’re sexually active, depending on their sexual practices.

Notifying Sexual Partners

If you test positive for chlamydia, you should communicate this result to all sexual partners with whom you were intimate in the 60 days before the onset of symptoms or before your diagnosis — whichever is earlier. This recommendation applies to partners of all genders, with whom you’ve had anal, oral, or vaginal sex.

In some states, your healthcare provider is allowed to prescribe extra doses of antibiotics for you to give to your sexual partners — a practice known as expedited partner therapy (EPT). This practice has been shown to reduce the rate of chlamydia reinfection in the original person seeking treatment, as well as increase the reported rate of sexual partners getting treatment.

Prognosis of Chlamydia

“Chlamydia can be cured easily if it’s caught early,” Rabin says. If you receive prompt treatment with antibiotics, you can avoid the most damaging effects of chlamydia, such as severe pain or infertility in women.

If chlamydia isn’t promptly detected and treated, on the other hand, it can lead to a number of potentially serious complications.

If you become infected with chlamydia, any initial symptoms may occur one to three weeks after the time of infection. But in many people who test positive for chlamydia, there are no symptoms, and it’s impossible to pin down how long they’ve had the infection.

Chlamydia doesn’t go away on its own without treatment. If you don’t get treated, you may develop serious symptoms or complications.

If left undiagnosed and untreated, chlamydia can lead to serious complications in both women and men.

In women, untreated chlamydia can lead to the following complications:

• Pelvic inflammatory disease (PID)
• Cystitis (bladder inflammation)
• Cervicitis (cervix inflammation)
• Preterm delivery during pregnancy

PID, a serious infection of the reproductive organs, occurs with symptoms in about 10 to 15 percent of women with untreated chlamydia. But with or without symptoms, it can cause permanent damage to the fallopian tubes, uterus, and surrounding tissues, potentially resulting in chronic pelvic pain, infertility, or ectopic pregnancy (a sometimes fatal condition).

Cervicitis can sometimes cause a yellowish discharge from the cervix.

In men, untreated chlamydia can lead to the following complications:

• Prostatitis (inflammation of the prostate gland)
• Epididymitis (inflammation of the epididymis, a structure found behind each testicle)
• Scarring of the urethra
• Infertility

Prostatitis can come on gradually or suddenly, potentially causing severe pain.

In both women and men, chlamydia can increase the risk of HIV infection if you’re exposed to the virus.

The prevalence of chlamydia is drastically different across racial and ethnic groups in the United States. Overall, Black, American Indian and Alaska Native, and Native Hawaiian and other Pacific Islander women have the highest rates of chlamydia, according to the CDC.

In 2017, the reported rate of chlamydia in Black Americans was 5.6 times the rate of white Americans. Among Native Americans and Alaska Natives, this number was 3.7, and for Native Hawaiians and other Pacific Islanders, it was 3.4. Hispanic Americans were 1.9 times as likely to have chlamydia as white Americans, while Asian Americans were only 0.6 times as likely.

Among young women ages 14 to 24, the CDC estimates that the prevalence of chlamydia is about 10 percent for Mexican Americans, and about 8 percent for Black girls and women. This number is only about 2 percent for non-Hispanic white girls and women.

You can protect your sexual health and fertility by educating yourself about STDs, as well as about healthy relationships and sexuality. If you’re sexually active, you should also get screened for STDs according to guidelines from the CDC.

The following resources can help provide information, support, and services related to sexual health.

CDC — Sexually Transmitted Diseases (STDs)

This online resource from the leading public health agency in the United States provides an overview of numerous STDs and related conditions, covering areas including prevention, testing, treatment, and statistics.

American Sexual Health Association

This nonprofit organization has online resources covering a wide range of topics, including STDs, sexual anatomy, sexual health in relationships, and talking to your kids about sex. It also has an online support group and discussion community with areas for specific STDs, STD prevention, and emotional and relationship issues.

National Coalition for Sexual Health

This coalition of more than 120 member organizations supports improving sexual health for all Americans by promoting high-quality sexual health information and health services. Its website has resources for the public and for healthcare providers, on topics like preventive health services, sexual health quick tips, and how to discuss sexual health at a doctor’s appointment.

Office on Women’s Health

This division of the U.S. Department of Health and Human Services provides information on numerous topics related to sexual and reproductive health, including STDs, relationships and safety, breastfeeding, and much more.

Planned Parenthood

This nonprofit organization operates clinics throughout the United States that provide STD testing and treatment, birth control, emergency contraception, abortion, and other sexual health services.

Learn More About Sexual Health Resources

Additional reporting by Quinn Phillips.