What is chlamydia?

Chlamydia is a sexually transmitted bacterial infection caused by an organism called Chlamydia trachomatis. Chlamydia is thought to be the most common of all the sexually transmitted diseases.

Although chlamydia is easily treatable, many people do not even know that they have it until complications occur. It is spread by direct person-to-person contact, usually during sexual intercourse, although pregnant women can pass it on their child during the birth. Chlamydia can also be spread by oral-genital contact resulting in an infection in the throat. There is no evidence to show that the infection can be passed via toilet seats or sharing towels.

What are the symptoms?

Around three quarters of people infected with chlamydia will not have any symptoms unless there are complications. In people who do get symptoms these will usually occur between a week to a month after infection. Men are more likely than women to have symptoms.

Chlamydia is the most common cause of non-specific urethritis (NSU) in men. Symptoms in men include the following: pain or burning on urination; milky or mucus-like discharge from the penis; swelling of the testicles; and irritation around the opening of the penis. The symptoms may seem to come and go but the infection will remain unless it is treated.

Chlamydia is often 'silent' in females and as many as nine out of 10 infected women will not have any symptoms. If symptoms do occur they include: pain or stinging on urination; milky or mucus-like discharge; painful intercourse; bleeding between periods; and abdominal pain. If left untreated, chlamydia can cause complications such as pelvic inflammatory disease (PID) and fertility problems. In men it can affect sperm function and fertility, and may also cause prostatitis (an infection of the prostate gland).

Chlamydia can also infect the rectum in men and women, either through anal sex, or possibly via spread from the cervix and vagina. Symptoms include rectal pain, discharge or bleeding ('proctitis').

Are any tests necessary?

If your doctor thinks you may have chlamydia he or she will use a cotton swab to collect cells from your genitals - from the cervix (neck of the womb) in women, or from inside the urethra in men. The swab will then be sent away to a laboratory for testing. Newer tests are now available which can detect infection in a urine sample.

How is chlamydia treated?

Chlamydia is treated with antibiotics. The antibiotics usually prescribed include azithromycin, doxycycline and ofloxacin.

Further information available from:

Your local hospital - Ask for the Genito-Urinary Medicine (GUM) or Sexual Health clinic.

FPA (Sexual Health Charity)
23-28 Penn Street
London N1 5DL
Tel: 020 7608 5240

Fact sheet provided by MIMS

Date last reviewed: October 2014

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