What is chlamydia? Common signs and symptoms

In 2024, more than 1.5 million of cases of chlamydia were reported in the U.S. Chlamydia is a sexually transmitted infection (STI) spread through sexual activity or from birth parent to baby, if the birth parent has the infection during childbirth. Anyone who engages in anal, oral or vaginal sex without a condom can get chlamydia from a partner who has chlamydia.

Not everyone with an infection will have chlamydia symptoms, but this post will outline common symptoms as well as provide information about diagnosis and prevention.

In this article:

What is chlamydia?

Chlamydia is the most common STI in the U.S., and it is caused by the bacteria that is passed from person to person through having condomless sex or from touching the genitals of a person who is infected.

Vaginal sex, oral sex, and anal sex can all spread chlamydia, and same-sex partners can also become infected. Even if an infected person doesn’t show symptoms, they can still spread the infection to others, which is why it is sometimes called a “silent infection.”

Chlamydia is more prevalent in women. Using condoms every time someone has sex can help reduce people’s risk of getting an STI. (For the purposes of this article, “women” and “men” refer to biological sex.)

Chlamydia may not have symptoms

Oftentimes, people infected with chlamydia don’t show any signs of infection. This means they might not even be aware they have chlamydia, but they can still infect someone else without realizing it.

If left untreated, chlamydia (whether someone has symptoms or not) poses health risks. Untreated chlamydia can harm the reproductive system, and it may cause infertility and pelvic pain. It can also increase someone’s chances of getting or passing on human immunodeficiency virus (HIV).

Common symptoms of chlamydia

While most people who are infected with chlamydia don’t show any symptoms, some people may have mild symptoms. Here are a few symptoms people should look out for:

• Common symptoms in women:
  • A burning sensation when urinating
  • A fever
  • Nausea
  • Pain during sex
  • Pain in the lower back
  • Unusual discharge from the vagina
  • Vaginal bleeding in between menstrual periods
• Common symptoms in men:
  • A burning sensation when urinating
  • Unusual discharge from the penis
  • Testicular pain and swelling (This symptom is not as common.)

Chlamydia can spread to the rectum, and if this happens, both men and women might have symptoms like discharge, pain and bleeding from the rectum.

Chlamydia complications

If chlamydia isn’t found and treated right away, it can cause health issues, including those listed below.

Epididymitis

Epididymitis is when there’s swelling (known as inflammation) in the epididymis, the tube in the back of the testicle that contains sperm. People with epididymitis might experience symptoms like fever, pain in the testicles and swelling.

Pelvic inflammatory disease (PID)

Pelvic inflammatory disease (PID) occurs when reproductive organs — such as the fallopian tubes, ovaries and uterus — become infected. Untreated chlamydia is a common cause of PID. It can cause scar tissue on reproductive organs, which can lead to other health problems, including:

• Ectopic pregnancy, where a fertilized embryo grows outside of the uterus, usually in a fallopian tube, which is a medical emergency
• Pain in the pelvic area
• Problems getting pregnant or staying pregnant, known as infertility

PID can be treated with antibiotics, but getting PID diagnosed as soon as possible can help avoid these complications.

Infertility

In women, PID can cause harm to the reproductive system, which might result in infertility. Men can potentially experience infertility as a complication of chlamydia infection, but it’s not as common.

Reactive arthritis

A chlamydia infection may also cause reactive arthritis, which can occur in both men and women. This type of arthritis is from a reaction to an infection in the body.

Diagnosing chlamydia

People can find out if they have chlamydia by going to a health care provider and giving a urine sample. Another way a health care provider might test for chlamydia is by using a cotton swab to take a fluid sample from the cervix, rectum, vagina or throat.

Getting tested by a health care provider is recommended if someone suspects they might have chlamydia to confirm diagnosis and treatment.

If someone tests positive for a chlamydia infection, they should let any sexual partners know so they can be tested as well. It is possible to become reinfected with chlamydia, so it’s important to avoid having sex until the person with chlamydia and any sexual partners have been successfully treated. People diagnosed with chlamydia should talk with a health care provider about when it’s safe to resume having sex.

When to seek medical attention

If someone notices any symptoms, it’s important to get tested for chlamydia so they can begin treatment with antibiotics right away. If someone finds out a sexual partner has chlamydia, they should contact a health care provider and get tested.

Screening for chlamydia

Sexually active women who are under age 25 should have yearly chlamydia testing. This includes those who are pregnant. Women over age 25 should be screened if they’re at a higher risk of getting chlamydia.

Here are a few reasons someone might be considered higher risk:

• They have a new sex partner
• They have multiple sex partners
• They have a partner with an STI or who has had a previous STI

At this time, there are no recommendations for men who are at low risk to be screened routinely. However, men can be considered for screening in certain scenarios, such as men who have sex with other men.

Chlamydia treatment

Chlamydia is a common STI that doesn’t always have symptoms, and it is if left untreated, it can cause serious health issues. Preventative measures, like getting an STI screening and practicing safe sex, can help reduce the risk of an infection. If someone is worried they might have chlamydia, a diagnosis can be done by a health care provider, including at a CVS Health MinuteClinic location. Chlamydia can be treated with antibiotics, but it’s still possible to get reinfected if someone has sex with a partner who has chlamydia.

Key takeaways

Chlamydia is a common STI that can be spread through sexual contact. It can also be spread during childbirth from a pregnant person to their child. People who are infected with chlamydia don’t always show signs of infection. When they do show symptoms, these may include a burning sensation when urinating or unusual discharge from the genitals. When left untreated, chlamydia can cause other health issues, including epididymitis, PID, infertility and reactive arthritis. Someone with chlamydia can be treated with antibiotics.