What Is It?

Chlamydia (pronounced: kluh-mid-ee-uh) is a sexually transmitted disease (STD) that is caused by bacteria called Chlamydia trachomatis. Although you may not have heard its name, chlamydia is one of the most common STDs. Because there often aren’t any symptoms, though, lots of people can have chlamydia and not know it.

The bacteria can move from one person to another through sexual intercourse, and possibly through oral-genital contact. If someone touches bodily fluids that contain the bacteria and then touches his or her eye, a chlamydial eye infection is possible. Chlamydia also can be passed from a mother to her baby while the baby is being delivered. This can cause pneumonia and conjuntivitis, which can become very serious for the baby if it’s not treated. You can’t catch chlamydia from a towel, doorknob, or toilet seat.

How Does a Girl Know She Has It?

It can be difficult for a girl to know whether she has chlamydia because most girls don’t have any symptoms. Chlamydia may cause an unusual vaginal discharge or pain during urination. Some girls with chlamydia also have pain in their lower abdomens, pain during sexual intercourse, or bleeding between menstrual periods. Sometimes a chlamydia infection can cause a mild fever, muscle aches, or headache.

How Does a Guy Know He Has It?

Like a girl, a guy can also have a difficult time telling whether he has chlamydia. Some guys may have a discharge from the tip of the penis (the urethra — where urine comes out), or experience itching or burning sensations around the penis. Rarely, the testicles may become swollen. Many times, a guy with chlamydia may have few or no symptoms, so he might not even know he has it.

When Do Symptoms Appear?

Someone who has contracted chlamydia may see symptoms a week later. In some people, the symptoms take up to 3 weeks to appear, and many people never develop any symptoms.

What Can Happen?

If left untreated in girls, chlamydia can cause an infection of the urethra (where urine comes out) and inflammation (swelling and soreness caused by the infection) of the cervix. It can also lead to pelvic inflammatory disease (PID), which is an infection of the uterus, ovaries, and/or fallopian tubes. PID can cause infertility and ectopic (tubal) pregnancies later in life.

If left untreated in guys, chlamydia can cause inflammation of the urethra and epididymis (the structure attached to the testicle that helps transport sperm).

How Is It Treated?

If you think you may have chlamydia or if you have had a partner who may have chlamydia, you need to see your family doctor, adolescent doctor, or gynecologist. Some local health clinics, such as Planned Parenthood, can also test and treat people for chlamydia.

The doctor will do an exam that may include swabbing the vagina or penis for secretions, which will then be analyzed. Sometimes doctors can diagnose chlamydia by testing a person’s urine. Talk to your doctor about which test is best for you. And let the doctor know the best way to reach you confidentially with any test results.

If you are diagnosed with chlamydia, the doctor will prescribe antibiotics, which should clear up the infection in 7 to 10 days. Anyone with whom you’ve had sex will also need to be tested and treated for chlamydia because that person may be infected but not have any symptoms. This includes any sexual partners in the last 2 months or your last sexual partner if it has been more than 2 months since your last sexual experience. It is very important that someone with a chlamydia infection abstain from having sex until they and their partner have been treated.

If a sexual partner has chlamydia, quick treatment will reduce his or her risk of complications and will lower your chances of being reinfected if you have sex with that partner again. (You can become infected with chlamydia again even after you have been treated because having chlamydia does not make you immune to it.)

It’s better to prevent chlamydia than to treat it, and the only way to completely prevent the infection is to abstain from all types of sexual intercourse. If you do have sex, use a latex condom every time. This is the only birth control method that will help prevent chlamydia.

Chlamydia Overview

Chlamydia is a bacterial infection disease transmitted when people have sexual relations. It is the most common sexually transmitted disease (STD) in the United States. Among adults, about 5% of the population is estimated to be infected. Among sexually active adolescent females, about 10% are infected.

Infection with chlamydia is most commonly found among the following groups:

    • Young adults


    • People living in urban areas


    • African Americans


  • Those with lower social and economic status

Chlamydia Causes

Chlamydia is an infection caused by the bacterium Chlamydia trachomatis. The infection is transmitted in 2 ways:

    • From one person to another by close personal contact such as through sexual intercourse (not by casual contact such as a handshake).


  • From mother to child with passage of the child through the birth canal. Chlamydia can cause pneumonia or serious eye infections in a newborn, especially among children born to infected mothers in developing countries.

Chlamydia Symptoms


    • No symptoms in 70-80% of cases (One study found that 3% of a sample of young adults 18-35 years had untreated chlamydia.)


    • Bleeding after sexual relations or between menstrual periods


    • Lower abdominal pain and burning pain during urination


  • Discharge from the vagina


    • Like women, men who are infected may not show symptoms. Estimates of those with no symptoms range from 25% to 50% of infected men.


    • Discharge from the penis


    • Pain, burning during urination


  • Inflammation or infection of a duct in the testicles, tenderness or pain in the testicles

When to Seek Medical Care

When to call the doctor

    • Fever


    • Abdominal pain


    • Discharge from the penis or vagina


    • Pain with urination


    • Frequent trips to the bathroom to urinate


  • Sexual contact with an infected person: Most often, a sexual partner is informed about a chlamydial infection, and this is the first indication of the presence of the disease. All partners of an infected person should be treated to prevent the spread of the infection back and forth.

When to go to the hospital

Chlamydial infections can develop into serious medical conditions if not treated.

    • Women: Pelvic inflammatory disease is a serious medical condition, which can lead to sterility. Fever, abdominal pain, and vaginal discharge can be symptoms of this disease. Women with these symptoms need to go to a hospital’s emergency department immediately for treatment.


  • Men: Fever, discharge from the penis, and painful urination may signal an infection, which may involve inflammation of the testicles. Men with these symptoms need to go to a hospital’s emergency department immediately for treatment.

Exams and Tests

The doctor will conduct a physical examination. Tenderness for women in the area of the sex organs, pus from the vagina or penis along with a high white-blood-cell count, and fever could indicate an infection.

The doctor will order diagnostic tests that may include looking at samples of the discharge under a microscope or obtaining cultures to identify the disease-causing bacteria.

The doctor will order diagnostic tests that may include obtaining cultures or sending urine to the laboratory to determine if you are infected. The doctor may also test you for other sexually transmitted diseases because many patients with Chlamydia also have other infections such as gonorrhea or trichomonas.

Chlamydia Treatment


The doctor may prescribe a single-dose antibiotic, such as azithromycin (Zithromax), taken as a pill. On the other hand, the doctor may choose an antibiotic, such as doxycycline (Atridox, Bio-Tab), to be taken as a pill twice a day for a week. Up to 95% of people will be cured after one course of antibiotics.


The doctor may prescribe a single-dose antibiotic, such as azithromycin (Zithromax), taken as a pill. On the other hand, the doctor may choose an antibiotic, such as doxycycline (Atridox, Bio-Tab), to be taken as a pill twice a day for a week. Up to 95% of people will be cured after one course of antibiotics.

Next Steps


    • Finish the entire course of antibiotics your doctor prescribes, even if you’re feeling fine and symptoms go away.


    • Notify any and all sexual partners of infection. They should be treated or tested so the infection is not passed back and forth.


    • Be retested if your symptoms continue or you think you have been reinfected. Having the infection once does not confer immunity to repeat infection.


  • Use latex condoms during sexual intercourse.


    • Use latex condoms when having sexual intercourse.


    • Avoid sexual contact with high-risk partners.


  • Treat infected sexual partners or have them tested before having sexual relations. Up to one-fourth of sexual partners will be reinfected because the partner wasn’t treated.


Treated with antibiotics, chlamydial infections can be cured 95% of the time.

  • Complications if not treated:
      • 10-40% of women will develop pelvic inflammatory disease; 5% of women with pelvic inflammatory disease will develop a form of liver disease (perihepatitis).


      • Women may develop chronic pelvic pain and become sterile due to blockage of the Fallopian tubes that allow the egg to be transported from the ovary to the women’s womb.


      • More common in men, some may develop sexually acquired reactive arthritis or Reiter syndrome.


    • Men may experience painful swelling of the testicles.