Chlamydia is one of the most common sexually transmitted infections (STIs) in the UK. You’re more likely to be infected if you’re under 25 and sexually active, but it can affect anyone. Though it’s easy to treat, it’s largely symptomless and often goes undetected. 

Left untreated, chlamydia can cause long-term complications, particularly in women.

Chlamydia is passed on through unprotected sex or direct contact between your genitals and someone else’s, even where there is no penetration or ejaculation. 

You can catch it by sharing sex toys that are not washed between use or covered with a condom, and by getting infected semen or vaginal fluid in your eye.  

It’s also possible for a pregnant woman to pass it onto her baby.

You can have chlamydia without knowing you’ve got it – often the symptoms are so mild that they go unnoticed. About 70% of females and half of all men will show no signs of having the infection, but where symptoms are present, they include: 

in women 

• Unusual vaginal discharge 
• Pain when urinating
• Pain in the stomach or pelvis
• Bleeding after sex or between periods 
• Pain during sex 

in men 

• White, cloudy, or watery discharge from the tip of the penis 
• Pain when urinating
• Burning or itching in the urethra (the tube that carries urine out of the body)  
• Pain in the testicles 

It can take weeks or even months for the symptoms to appear after being infected.

The only way to know for sure if you have chlamydia is to undergo a test, but this doesn’t necessarily mean that you have to be examined by a doctor or nurse. To test for chlamydia, you need to provide a sample of cells – there are two ways to do this: 

• Using a swab to wipe over the area that might be infected e.g., vagina or anus 
• Urinating into a container (the most common method used for men) 

You can expect to receive the results back from the laboratory within 7 to 10 days.

It’s also possible to buy a self- test kit that you can use at home to diagnose chlamydia.

If you are under 25 and sexually active, then you should get tested for chlamydia every year or when you have sex with new or casual partners. 

You should also arrange a test if: 

• You or your partner has symptoms of chlamydia or another STI 
• You or your partner has had unprotected sex with another person    

If you’ve had sex with someone that you know has chlamydia then you should get tested. You should take the test without delay, however it is important to know that the early stages of this STI do not always show up, so you may need to take another test at a later date to be sure.

If chlamydia is left untreated in a woman, it can spread to the womb, fallopian tubes, and ovaries. This is a common cause of pelvic inflammatory disease (PID), which can lead to difficulty getting pregnant and an increased risk of ectopic pregnancy. 

In men, chlamydia can cause inflammation of the testicles and in some cases a form of arthritis, known as sexually acquired reactive arthritis (SARA).

There are very few visual symptoms of chlamydia. The only way to know for sure that you have it, is to undergo testing at a sexual health or GUM (genitourinary) clinic. 

The most obvious signs are unusual discharge from the vagina or tip of the penis, and in women bleeding between periods or after sex. If you have any of these symptoms, or you think you may have chlamydia, contact your GP for advice on what to do next. 

Your doctor won’t be able to diagnose chlamydia on sight, but they can perform an examination with your consent or arrange for further tests at a clinic.

If you think you may have chlamydia, then your sexual partners will need to be tested. 

If you have been diagnosed with chlamydia, your partner’s doctor or nurse may decide to start them on antibiotics straight away, because it’s highly likely they have it. 

It’s important to remember that though you may not have had symptoms at the time of having sex, you could still have been infectious. The staff at your local sexual health clinic can help you tell your recent sexual partners in a way that protects your identity.

Chlamydia can be passed on via oral sex, if you or your partner has the infection. When you have oral sex, bacteria is transferred from the throat to the penis, vulva or anus.

Around 95% of people with chlamydia who take a full course of antibiotics make a complete recovery. Left untreated, chlamydia can cause serious, long-term health problems, particularly in women who may suffer damage to their reproductive system. 

The only way to know if you have chlamydia is to get tested regularly.

There is no particular timeframe in which chlamydia can cause damage. Treatment is more effective when the infection is found early, which is why we encourage high-risk groups, like the under 25s, to get tested regularly.

It’s not possible to get chlamydia from kissing or casual contact.

Chlamydia is usually treated with a course of antibiotics. There are two main types: 

• Doxycycline — two capsules a day for seven days 
• Azithromycin — a 1g dose, followed by two 500mg tablets over two days

Doxycycline is the most commonly prescribed in the UK, with azithromycin used as an alternative for patients who aren’t able to tolerate doxycycline. 

To prevent the infection being passed on we recommend that you avoid having sex until you have completed your course of treatment (or up to a week after if you have taken azithromycin).

It’s highly unlikely that chlamydia will go away on its own. To stop the infection from spreading, your doctor or pharmacist will prescribe a course of antibiotics.

It is possible to get rid of chlamydia. Around 95% of patients who take a full course of antibiotics are completely cured of chlamydia.

Following diagnosis, with the right treatment, you can expect chlamydia to last for 1 to 2 weeks. If your symptoms do not clear within 14 days of treatment should contact your doctor or a sexual health clinic.  

It is possible to have chlamydia without knowing; it can remain in your system for weeks or even months before you notice any symptoms or until it shows up on a test.

You should wait at least six weeks after treatment before you re-test. If you test earlier than this you may return a positive result even after you are clear of the infection.

Most patients with chlamydia are prescribed doxycycline. Patients who cannot tolerate this type of antibiotic are given azithromycin instead. The two medicines are both used to treat uncomplicated urogenital chlamydia, but they work in different ways. 

• Doxycycline — one capsule taken twice a day, over seven days 
• Azithromycin — a 1g dose, followed by two 500mg tablets over two days

If your doctor or pharmacist thinks that it is highly likely you have chlamydia, for example if you’ve had unprotected sex with someone who has the infection, then they will start you on a course of antibiotics before your test results come back.

If your symptoms clear up after treatment then it’s likely that the antibiotics have worked. However, you will need to be re-tested if: 

• You still have the symptoms of chlamydia 
• You didn’t finish taking the course of antibiotics 
• You had sex before you and your partner finished treatment 
• You’re pregnant 

If you tested positive for chlamydia and you are under 25, then you are at higher risk of catching chlamydia again and should be re-tested after three to six months.

Most people don’t know when they have chlamydia – around 70% of females and half of all men will show no signs of having the infection. Where the symptoms are present, they are usually mild and often go unnoticed. You may experience unusual vaginal discharge, bleeding between periods or after sex (in women) and pain when urinating.  

The only way to know for sure if you have chlamydia is to get tested. You can do this at your local sexual health or genitourinary (GUM) clinic, or using a self-test kit at home.