A sexually transmitted infection (STI) caused by the bacterium Chlamydia trachomatis. It is one of the most common STIs worldwide and can affect both men and women.
Chlamydia is a common sexually transmitted infection (STI) caused by the bacterium Chlamydia trachomatis. It affects both men and women and is one of the most widespread STIs globally. Because it frequently produces no symptoms, many individuals may have the infection without realizing it, which contributes to its rapid spread.
What Is Chlamydia?
Chlamydia is transmitted through sexual contact involving the genitals, mouth, or rectum. The infection can occur in multiple areas of the body, including:
- Genital tract
- Throat
- Rectum
- Eyes (less common but possible through hand-to-eye contact or during childbirth)
Newborns can contract the bacteria from an infected mother during delivery, leading to eye infections or respiratory issues. These forms have different clinical presentations and require medical attention.
Why Early Testing Matters
Because chlamydia often causes no symptoms, regular screening is essential—especially for sexually active individuals under 25, those with new or multiple partners, or anyone who has had unprotected sex. If left untreated, chlamydia can lead to serious complications such as pelvic inflammatory disease (PID), infertility, or chronic pelvic pain in women, and reproductive or urinary issues in men. Fortunately, when detected early, chlamydia can be treated effectively with antibiotics.
Symptoms of Chlamydia
When symptoms do occur, they depend on the site of infection.
Genital Symptoms
In men:
- Clear or cloudy discharge from the penis
- Burning or pain during urination
- Testicular discomfort or swelling (less common)
In women:
- Abnormal vaginal discharge, which may appear watery or change in color
- Painful or burning urination
- Lower abdominal pain or pelvic discomfort
- Vaginal bleeding between periods or after sexual intercourse
Rectal Symptoms
(Seen in individuals who engage in receptive anal sex)
- Pain or discomfort in the rectal area
- Discharge or mucus from the rectum
- Rectal bleeding or irritation
Throat Symptoms
(Occur after oral exposure to an infected partner)
- Sore throat
- Irritation or mild discomfort
- Rarely, swollen lymph nodes in the neck
Prevention and Care
Safe sexual practices—including consistent condom use, regular STI testing, and open communication with partners—help reduce the risk of infection. Anyone who suspects exposure should seek prompt medical evaluation. Completing the full course of prescribed antibiotics and abstaining from sexual activity until treatment is finished are important steps to prevent reinfection and spread.
