Conditions and diseases


Symptoms and causes

Symptoms and causes

What is it?

Chlamydia is a sexually transmitted infection (STI) caused by the bacterium Chlamydia trachomatis. It is the most common STI in the world. Chlamydia bacteria nestle into the mucous membranes of the genitals. This leads to an inflammation of the urethra, the cervix and sometimes the anus.


Typical symptoms are a purulent discharge and pain while urinating. The symptoms and consequences of a chlamydia infection can vary greatly in women and men.

In women

In general, the most common symptoms that may indicate chlamydia:

  • more or different secretions than normal
  • pain while urinating
  • abnormal blood loss, e.g. between two menstrual periods or after sex
  • pain during sex
  • pain in the lower abdomen

Sometimes, a woman does not notice that she is infected with chlamydia.

Chlamydia can spread to the internal organs (uterus, fallopian tubes and ovaries). Once the fallopian tubes are affected, the infection can spread further into the abdominal cavity. Such extensive infection of the lower abdomen is called PID (Pelvic Inflammatory Disease) and is a serious condition. Fallopian tube inflammation can be accompanied by fever, abdominal pain and a general feeling of sickness. Provided it is treated quickly with antibiotics and bed rest, a fallopian tube infection can be completely cured. A fallopian tube infection that is not treated, or treated too late, can develop into a PID: this infection can eventually result in scars in the fallopian tubes that lead to infertility.

Chlamydia may also affect the anus. This then causes additional symptoms of bloody discharge, irritation, itching and pain with bowel movements.

A pregnant woman can transfer chlamydia to her baby during childbirth. The baby may develop Chlamydial conjunctivitis or pneumonia. Proper treatment of a woman during her pregnancy will avoid the risk for your child.

In men

In men, a chlamydia infection often causes clearer and quicker recognisable symptoms: after just one to several weeks after being infected with chlamydia, there is usually a dripping discharge from the urethra. This secretion is sometimes aqueous, sometimes whitish (suppurative) in consistency. Peeing can also be painful. However, a large proportion of infected men also have no symptoms of a chlamydia infection.

In men, too, the inflammation can spread to other organs. This is much less common than in women. The bacteria (and inflammation) can enter the prostate and epididymis through the vas deferens. This can lead to epididymis inflammation. This inflammation is then accompanied by severe pain in the scrotum, sometimes radiating into the groin. Epididymis inflammation can also cause an inflammation of the testicle itself. This also results in swelling and pain. Sometimes a chlamydia infection spreads to the prostate. This mainly causes urinary problems and fever.

Chlamydia does not always cause obvious symptoms. Unfortunately: even without symptoms, chlamydia is contagious and can be transmitted.

Diagnosis and treatment

Diagnosis and treatment

Chlamydia is treated with antibiotics. One of the following antibiotics are used:

  • Zitromax
  • Erythromycin
  • Ciprofloxacin

It is important to know that experiencing a chlamydia infection does not offer any protection for the future: in other words, you can develop another chlamydia infection. Protected sexual contact is therefore indicated (not only for this reason).

Treatment centres and specialisations

Treatment centres and specialisations

Latest publication date: 14/05/2024
Supervising author: Dr Ameye Filip