Reviewed by: HU Medical Review Board | Last reviewed: February 2021 | Last updated: March 2021
Chlamydia is the most common bacterial sexually transmitted infection (STI) in the United States. It is caused by the bacteria Chlamydia trachomatis.1
Chlamydia can cause inflammation of the cervix, uterus, and fallopian tubes. It can also affect the urethra (the tube that carries urine from the bladder to the outside of the body), the anus, and the throat.1
Chlamydia is most common in young, sexually active people. It is hard to estimate how common chlamydia is because it is often asymptomatic. This means it may not have any symptoms.1
Chlamydia can be transmitted through semen and vaginal fluid at any point during oral, vaginal, or anal sex. Ejaculation does not need to occur. It can also be transmitted through sex toys if shared between partners and not properly cleaned.
It is not transmitted by other forms of contact like sharing utensils, sharing towels, kissing, or hugging.1
How is chlamydia related to HIV?
Chlamydia has a link to HIV. Both conditions often occur together. There are several reasons why this might happen.
HIV and chlamydia share similar risk factors. These include having multiple sexual partners and not using condoms regularly. Sores or blisters that come along with certain STIs cause breaks in the protective barrier of the skin. This makes it easier for HIV, chlamydia, and other STIs to be transmitted.1-3
Having an STI like chlamydia along with HIV can impact how both conditions are transmitted. For example, untreated chlamydia with HIV makes it more likely that a person will transmit HIV to their partner. The risk of HIV transmission is thought to be even higher if a person’s HIV is not suppressed with medicine. It is also possible for chlamydia and HIV to be transmitted at the same time.1-3
There are often shared barriers to healthcare, testing, and treatment that can lead to HIV and chlamydia occurring together. These include:1-3
- Issues with access to care
- Trouble paying for healthcare or medicines
- Problems with consistent transportation
- Stigma related to HIV and other STIs
Trouble accessing healthcare and feelings of stigma may decrease a person’s ability or desire to see their doctor. This can lead to decreased testing, prevention measures, and treatment.
Signs and symptoms
More than 75 percent of people with chlamydia have no symptoms at all. If a person does have symptoms, it may take several weeks after transmission for them to appear.1
A person may have different symptoms based on what area of the body is affected, such as:1
- Cervix (the area between the vagina and uterus). Mucus-like discharge, heavy periods, bleeding between periods, painful urination, and frequent urination
- Uterus and fallopian tubes. Pelvic pain, abdominal pain, fever, and pain with movement of the cervix
- Urethra. Watery discharge or mucus with painful urination
- Testicles. Swelling and tenderness of 1 or both testicles
- Rectum. Anal discharge, pain, or bleeding
Other areas of the body that can be affected by chlamydia include the eyes, joints, and throat. Symptoms in these areas are less common than symptoms in the reproductive tract.1
Testing for chlamydia
Diagnosing and treating chlamydia is very important. Untreated chlamydia can move upward through the cervix and uterus and cause pelvic inflammatory disease (PID). PID can lead to severe pain, problems with fertility, and ectopic pregnancies, which can be dangerous or life-threatening. Advanced PID might also affect the liver. If you are pregnant, it is also possible to transmit chlamydia to your baby during birth.1-3
Because chlamydia is often asymptomatic, it is possible for a person to have chlamydia for a long time without knowing. This is why it is often recommended that young, sexually active people and those who are pregnant regularly get tested for chlamydia and other STIs.1-3
Other people at high risk for chlamydia may also benefit from frequent testing. This includes those with multiple sexual partners or who do not regularly use condoms.1-3
What is the test like?
Urine tests and simple swabs of the vagina, cervix, rectum, or urethra can all detect chlamydia. These tests can be done at your doctor’s office, through your local health department, and sometimes even at home.1-3
How is chlamydia treated?
Once a person is diagnosed with chlamydia, they will take antibiotics to cure the infection. It is possible to get chlamydia again even after treatment. Waiting to have sex until after treatment is done can prevent reinfection.1-3
When a person is diagnosed with chlamydia, their sexual partners should also be tested. All partners with chlamydia need to finish treatment to prevent reinfection. Many doctors’ offices and health departments can help notify partners in a safe and anonymous way.1-3
Chlamydia is also often commonly transmitted with gonorrhea. When 1 is detected, it is common to be treated for both to be safe. Gonorrhea is also treated with antibiotics.1-3
Using condoms consistently can reduce the risk of getting chlamydia. This includes using a new condom after each sexual act and for the entirety of sex.1-3
Talking to your doctor about your risk and regular testing can be helpful. Regular testing in those at risk, even when symptoms are not present, can help detect silent infections and reduce the risk of transmission.1-3