Fast Facts
  • Chlamydia is a common and curable infection caused by the bacteria chlamydia trachomatis.
  • It is the most common reportable STI in the U.S. In 2018, there were nearly 1.8 million cases reported.
  • Most females with chlamydia and about half of males do not experience symptoms.
  • Chlamydia can cured with antibiotic treatment, but if left untreated it can lead to complications such as PID and, potentially, infertility.

How common is chlamydia?

Very. In the United States, chlamydia is the most common bacterial sexually transmitted infection (STI). In 2018, nearly 1.8 million cases of chlamydia were reported to the Centers for Disease Control and Prevention (CDC). However, it is estimated that almost 3 million cases actually occur each year.

Chlamydia is most common in younger people. It is estimated that 1 in 20 sexually active young women aged 14-24 years has chlamydia.

How does someone get chlamydia?

Chlamydia is passed through oral, anal, or vaginal sex. Chlamydia can be passed from one person to another even if the penis or tongue does not go all the way into the vagina or anus.Eye infections can occur when discharge caries the disease into the eye during sex or hand-to-eye contact.

Chlamydia can also be passed from mother to newborn as the baby passes through the infected birth canal. This can result in eye infections, pneumonia or other complications.

What are the symptoms of chlamydia?

It is important to understand that focusing on signs and symptoms is not very useful in determining if someone is infected with chlamydia. First, the symptoms of chlamydia are similar to the symptoms of gonorrhea, and the two infections are often confused. Also, approximately, most women and about half of men do not experience symptoms. So, most people who are infected will not be able to tell from symptoms.

If a person does have symptoms, they usually develop within one to three weeks after exposure to chlamydia. How long a person remains infectious (able to transmit the bacteria to others) is difficult to determine since so many people are asymptomatic. A person must be considered infectious from the time they become infected until treatment is completed.

If a person does have symptoms, they may include:

  • Proctitis (inflamed rectum), urethritis (inflamed urethra) and conjunctivitis (inflamed eyelid)
  • Soreness and redness in the throat or mouth (for chlamydia infection of the throat
  • vaginal discharge
  • pain or burning sensation during urination
  • pus (thick yellow-white fluid) or watery or milky discharge from the penis
  • pain or swelling of the testicle

If the infection spreads to the fallopian tubes, symptoms may include:

  • lower abdominal and lower back pain
  • pain during intercourse
  • bleeding between menstrual periods
  • nausea or fever

Who should get tested for chlamydia?

Because chlamydia is very common and often has no symptoms, anyone who is sexually active should think about being tested. Because chlamydia is very common among young women, The Centers for Disease Control and Prevention (CDC) recommend sexually active women age 25 or younger get tested once per year. Chlamydia testing is also recommended for women with new or multiple sexual partners and pregnant women.

Anyone who is sexually active should talk with a healthcare provider about whether they need testing for chlamydia or other STIs. Don’t be afraid to speak openly about your sex life, as you can get the best care by having an honest discussion with your healthcare provider.

How do you get tested?

There are several different reliable tests for chlamydia. Newer tests, called NAATs (short for nucleic acid amplification tests), are very accurate and easy to take. Your healthcare provider can explain what testing options are available (urine or swab tests, for example). If you don’t have a regular healthcare provider, you can search here for a clinic near you.

People infected with chlamydia are often also infected with gonorrhea, so patients with chlamydia are often treated for gonorrhea at the same time, since the cost of treatment is generally less than the cost of testing.

If you live in Alaska, Maryland, or Washington, D.C., you can have a free at-home chlamydia test. Visit for more information.

What is the treatment for chlamydia?

There are antibiotic treatments that are effective in treating chlamydia. A healthcare provider will decide which antibiotic is prescribed, taking into consideration the particular needs of the patient.

Whatever treatment is prescribed, there are some important points about any treatment:

  • The patient must take all medications as directed.
  • All partners should be examined and treated.
  • The infected person should not have sex until they and any partner or partners have been treated and cured.
  • People who show symptoms after treatment should be tested again.
  • Women should be retested three to four months after treatment because of a high rate of reinfection.
  • Because the symptoms of chlamydia are similar to the symptom of gonorrhea, and because a person can be infected with both, doctors will sometimes go ahead and treat people with chlamydia for both infections (chlamydia and gonorrhea). Remember, partners should be examined for infection and treated as well to avoid reinfection.

What does chlamydia infection mean for my health?

Chlamydia can be treated and cured easily, but that doesn’t mean that chlamydia infection isn’t potentially dangerous. If chlamydia isn’t diagnosed and left untreated, it can cause serious complications.

Untreated chlamydia infections in women may lead to:

  • Pelvic inflammatory disease (PID), a serious infection of the reproductive organs (uterus, fallopian tubes and ovaries). Left untreated, PID can cause infertility (and inability to become pregnant or maintain a pregnancy), chronic pelvic pain, or ectopic (tubal) pregnancy.
  • Cystitis (inflammation of the urinary bladder)
  • A condition called mucopurulent cervicitis, characterized by a yellow discharge from the cervix

Untreated chlamydia in men may lead to:

  • Prostatitis (inflammation of the prostate gland)
  • Scarring of the urethra
  • Infertility
  • Epididymitis (inflammation of the epididymis, which is the elongated, cord-like structure that runs along the back of each testes)

More about Pelvic Inflammatory Disease

For women, one of the most serious complications from untreated chlamydia is pelvic inflammatory disease (PID).

According to the Centers for Disease Control and Prevention, between 10–20% of women with untreated chlamydia and gonorrhea infections may develop PID. And 1 in 8 women with a history of PID experience difficulties getting pregnant. PID can also cause ectopic pregnancy (where a fertilized egg implants outside of the uterus) and chronic pelvic pain.

Like chlamydia, it is possible for a woman to have PID and not have any symptoms, or have symptoms too mild to notice, for an unknown period of time. If symptoms do occur, they could include:

  • Dull pain or tenderness in the lower abdomen
  • Burning or pain when you urinate (pee)
  • Nausea and vomiting
  • Bleeding between menstrual periods
  • Increased or changed vaginal discharge
  • Pain during sex
  • Fever and chills

PID can also be misdiagnosed as appendicitis, ectopic pregnancy, ruptured ovarian cysts or other problems.

PID can be treated successfully, if diagnosed and treated early. But any damage that may have been caused to the reproductive system cannot be reversed. This is why regular testing for chlamydia, and immediate treatment, is important.

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