Chlamydia is a very common sexually transmitted infection (STI) that often doesn’t cause any symptoms. If it isn’t treated it can cause serious long term problems for women and for men who have sex with men it dramatically increases the risk of acquiring HIV. It is estimated that only almost 75% of people who acquire chlamydia won’t be diagnosed. Most men with chlamydia will clear the infection naturally by about 6 months but for women it may take years for the infection to clear on its own.

How do you get chlamydia?

Chlamydia is a bacteria that can only survive inside of human cells. It can only therefore be transmitted through direct contact with mucous membranes. Mucous membranes are the flesh-coloured parts of your body that cover openings to the inside of you body like the lining of the throat, inside the eyelids, inside the vagina and inside the anus. Chlamydia can cause an infection in the throat via oral sex, in the cervix of the vagina via regular sexual intercourse and in the rectum via anal sex. The chance of passing on chlamydia during any one episode of sexual contact is between 6-17% which is fairly high compared to other STIs.

How is chlamydia diagnosed

It has become easy to diagnose chlamydia with urine samples or swabs. In men a urine sample will diagnose chlamydia that has infected the penis. In women a urine sample can also be used but is less reliable than a self-collected vaginal swab or a swab of the cervix collected by the doctor. Throat infections are diagnosed by a swab collected by the doctor and rectal infections can be diagnosed by a swab that is either self-collected or performed by the doctor.

Who should be tested for chlamydia?

Anybody with symptoms should be tested for Chlamydia. In people without symptoms testing should be provided to young people (under age 30) who are sexually active at least once a year. Annual testing is also recommend for men who have sex with men with testing up to 4 times per year if there is also a background of any unprotected anal sex, more than 10 sexual partners in the last 6 months, group sex or recreational drug use during sex. Chlamydia testing should also be provided to anyone who requests testing, to pregnant women and to people who have been sexually assaulted.

What happens when you get chlamydia?

Most of the time, no matter which part of the body is infected, there are no symptoms. If symptoms do develop it may not be for many weeks or even months after the infection actually happened.

In women who have an infection of the cervix there are no symptoms around 75% of the time. If there are symptoms they will be a discharge, burning pain on passing urine or bleeding after intercourse. If it’s not treated then in about 5% of women it can spread to the uterus where it can cause infertility or put women at risk of an ectopic pregnancy if they do fall pregnant. Ectopic pregnancies are very dangerous and often life threatening.

In men with a chlamydia infection at their penis there no symptoms about 50% of the time. If there are symptoms it will be a burning pain when passing urine and sometimes a slight discharge. Like women, if it’s not treated it will sometimes spread to infect the prostate or a part of the testicles called the epididymus.

In men and women it can sometimes affect the throat but it is very rare for it to cause any symptoms. Most anorectal infections don’t cause any symptoms either and if they do it would be anal pain and and bloody, mucous discharge. An anorectal infection in man who have sex with men puts them at much higher risk of acquiring HIV if they have sex with someone who is positive with a detectable viral load.

How is chlamydia treated?

Chlamydia is easily treated especially when it infects the throat or the genitals of men or women. The treatment is 1g of azithromycin taken once only (usually delivered as two 500mg tablets). Rectal infection is harder to treat and the recommend treatment is doxycycline 100mg twice a day for 7 days. The treatment duration is more complicated if chlamydia has spread to epididymus of the testes or to the uterus.

What follow up is needed?

A repeat test is recommended 3 months after a patient has been treated for chlamydia to identify any new infections. It’s not usually necessary to test to make sure chlamydia has been cured except in anal infection or pregnant women.

Following treatment, sexual intercourse should be avoided for 7 days to allow the antibiotics to work and it is important to let any partners from the at least the last 6 months know so they can also be tested and treated.