Chlamydia is one of the most common sexually transmitted infections (STIs). You might not know you are infected because it is often symptom-free but left untreated it can cause serious problems in both men and women. Testing for it is quick and painless, and it can be treated with a course of antibiotics.
Chlamydia is caused by bacteria which are found in infected semen, pre-cum and vaginal fluids.
Chlamydia symptoms
Symptoms might show within one to three weeks of infection, but around half of men and most women have no symptoms.
Chlamydia in the penis can cause:
– a whitish, cloudy or watery discharge
– pain when urinating
– burning or itching in the urethra (the tube that carries urine out of the body)
– pain and swelling in the testicles.
In the vagina, it can cause:
– a change in vaginal discharge
– pain when urinating
– pain in the belly or lower back
– pain during sex
– bleeding between periods or after sex.
In the rectum it generally causes no symptoms but might cause discomfort and discharge.
Chlamydia in the throat is usually symptom free.
In the eyes, it can cause pain, redness and discharge (conjunctivitis).

How it’s passed on
You can get chlamydia through:
– vaginal, oral or anal sex without condoms
– sharing sex toys that are not washed or covered with a condom each time they are used on a different person
– your genitals (penis, vagina or any other sexual anatomy that doesn’t fit the boxes) coming into contact with your partner’s genitals
– infected semen or vaginal fluid getting in your eye.
It’s not yet known whether chlamydia is spread on fingers when you touch an infected part of the body, then touch other parts of your body or someone else’s.
Using the external or internal condom cuts the risk. Other types of contraception, such as the contraceptive pill, offer no protection against STIs.
If you are living with HIV, having untreated chlamydia could make it more likely that you’ll pass on HIV during unprotected sex. But if HIV drugs have made your viral load undetectable then chlamydia or other infections don’t appear to make you more likely to pass on HIV.

Chlamydia tests and treatment
Chlamydia tests are simple and painless.
A sample of cells can be collected for testing in two ways:
– giving a sample of urine
– gently wiping a swab (small cotton bud) over the area that might be infected.
Swabs only take a few seconds and don’t hurt – they may be uncomfortable for a moment or two.
Chlamydia is treated with antibiotics. The most common treatments are:
– a single dose of Azithromycin
– a week-long course of Doxycycline.
You could pass on the infection if you have sex before treatment has finished. This includes vaginal, anal and oral sex, even with a condom. To prevent re-infection or passing the infection on, wait 7 days after your treatment has finished to have sex.
Even if you are given a single dose of antibiotics, you need to wait 7 days to have sex.
It is important that people you have had sex with recently are also tested and treated.

Untreated chlamydia
If chlamydia is not treated it can sometimes cause serious problems, including pain, inflammation and infertility in men, women, as well as all genders and sexual anatomies. It can also lead to complications in pregnancy.
Regular testing
The more people you have sex with, especially unprotected sex, the more chance there is of catching infections like chlamydia. You can have them without knowing, so regular check-ups are a good idea, especially if you are starting a new relationship and/or you want to stop using condoms with your partner.
Most people get tested and treated for infections like chlamydia at sexual health or GUM (genitourinary medicine) clinics. It’s free and confidential, so no one else, including your GP, will be told about your visit. Some GP surgeries also test for and treat these infections.