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    Chlamydia: diagnosis and treatment

    On this page
    1. What is chlamydia?
    2. How common is chlamydia in the UK?
    3. How is chlamydia spread?
    4. How do you catch chlamydia?
    5. Symptoms of chlamydia
    6. Can you get rid of chlamydia?
    7. Complications of chlamydia
    8. How to avoid catching chlamydia
    9. How to test for chlamydia 
    10. Chlamydia treatment

    Reviewed by Dr Tatjana Street

    Pack of condoms

    Chlamydia is a common STI that usually has no symptoms. The majority of infections are spread through unprotected sex. This article explains in more depth what chlamydia is, what symptoms, if any, you should be aware of and when to get tested. It also provides information on how chlamydia is spread, how to test for the STI and how it’s treated. 

    What is chlamydia?

    Chlamydia is a Sexually Transmitted Infection (STI) caused by the bacteria chlamydia trachomatis. It is the most common bacterial STI in the UK, and is usually transferred by having unprotected sex. In England, more than 159,000 people tested positive for the infection in 2021. 

    People can have chlamydia and not know about it, most people don't get any symptoms. That's why it's spread so easily: most people simply don't know that they have it. Thankfully, it can be very easily treated, but it is also very easy to reduce the risk of contracting it in the first place, by simply using condoms every time you have sex, particularly with a new partner.

    How common is chlamydia in the UK?

    Chlamydia is the most common STI in the UK, in 2021 51.2% of all new STI diagnoses were chlamydia. It is especially common in the under 25s. In 2021 over 87,000 people aged 15 to 24 were diagnosed with chlamydia in England, which is over 55% of all STIs in this age range. 

    Bear in mind, these figures only cover diagnosed cases of chlamydia – many people have the infection but don’t know they do.

    It's impossible to know exactly how many people have chlamydia. However, due to the ease with which chlamydia is spread and the fact that it usually doesn’t cause any symptoms, the actual number is almost certainly much higher. It is thought that around 2% of the general population in Europe have chlamydia.

    How is chlamydia spread?

    Many people think that STIs are transmitted solely through penetrative sex. In fact, chlamydia can be spread through:

    • Vaginal sex
    • Anal sex
    • Oral sex
    • Sharing sex toys
    • Genital contact
    • Genital fluids coming into contact with the eye

    How do you catch chlamydia?

    The first thing to know is that chlamydia can be spread through a variety of sexual activities. Chlamydia is caused by the bacteria chlamydia trachomatis, it’s a bacterial infection and is carried within genital fluids (vaginal fluid, semen, pre-cum and rectal mucus) -  you can get chlamydia if infected fluid comes into contact with your mouth, eyes, vagina or rectum. 

    It is primarily passed through unprotected sex (sex without a condom). One of the sexual partners must already have chlamydia in order to pass on the infection. You can’t catch chlamydia without direct contact with the infection.  

    Symptoms of chlamydia

    Most people have chlamydia without knowing that they have it. However, some people do get symptoms. These can differ between men and women, which is why it’s a good idea to know what to look out for. 

    Symptoms of chlamydia in men 

    • Discharge from penis which is white, cloudy or watery 
    • Burning sensation when urinating 
    • Epididymitis - painful swelling at the back of the testicle

    Symptoms of chlamydia in women 

    • Vaginal discharge that's different from your usual discharge
    • Bleeding between periods/during or after sex
    • Burning sensation when urinating
    • Pelvic inflammatory disease (PID) - PID causes lower abdominal pain, vaginal discharge, fever and can affect fertility if left untreated.

    If infected fluid has come into contact with the eye, you may develop conjunctivitis.

    Chlamydia symptoms

    Can chlamydia be symptomless?

    Chlamydia is notorious for its common lack of symptoms, meaning the infection can easily be caught without you realising. At least 50% of men and up to 70% of women display no symptoms of chlamydia. Therefore if you have unprotected sex with a new partner you should get an STI test regardless of how you might feel.

    Can you get rid of chlamydia?

    Because chlamydia is a bacterial infection, it can easily be treated with a 7 day course of  oral antibiotics. You need to take your antibiotics exactly as directed by your doctor.

    In the UK the current gold standard treatment is a week's course of Doxycycline. This has a much higher cure rate than the alternative treatment Azithromycin. It's also important not to have any sex during your treatment and get all partners tested and treated.

    How long does chlamydia last?

    It can take up to 14 days for chlamydia to show up in a test, so if you do the test too early after unprotected sex, it might come back negative. It's very rare for chlamydia to disappear on its own, if you have a positive test, you really do need to take treatment. Untreated chlamydia can lead to complications.

    Remember you are also likely to pass it on to any partners unless you have been treated. An uncomplicated infection is cured after seven days of treatment.

    Complications of chlamydia

    It’s important to bear in mind that chlamydia usually doesn’t cause any symptoms. This is problematic because, when left untreated, chlamydia can potentially lead to serious health complications. The complications of chlamydia can include:

    Pelvic inflammatory disease 

    In women, untreated chlamydia can lead to pelvic inflammatory disease, which can in turn cause ectopic pregnancy, chronic pain, and even infertility

    Inflammation in the testicles 

    In men, untreated chlamydia can cause inflammation in the testicles (orchitis) and/or inflammation in the tubes that carry sperm from the testicles (epididymitis). In some cases, this can lead to fertility problems.


    Occasionally chlamydia can cause  inflammation of the joints. This is  a type of arthritis called sexually acquired reactive arthritis (SARA). Most commonly the knee is affected, but other joints  can also be involved. Some people who get this, also get conjunctivitis.

    How to avoid catching chlamydia

    The best way to avoid chlamydia is to always use condoms when you aren’t certain that your partner is STI-free. It’s always a good idea to talk about your sexual history with a new sexual partner including any recent STIs tests you might have had. 

    Vaginal and anal sex

    For vaginal or anal sex, you should always use condoms correctly. Lubricants can help prevent condoms from splitting. If you are using latex condoms, you should not use oil-based lubricants as these can damage the condom.

    Oral sex

    For oral sex, you can use condoms to cover the penis and prevent the transmission of infected semen into the mouth or eyes. Dental dams can also be used for oral sex; these are thin, soft pieces of plastic or latex that are placed over the vagina or genital area, which provide a protective barrier. 

    Considering an STI test?

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    Sex toys

    When sharing sex toys, you can avoid the transmission of chlamydia and other STIs by washing the toys between uses or covering them with a fresh condom.

    How to test for chlamydia 

    Chlamydia can be tested for very easily. Because chlamydia is asymptomatic in so many people, it is essential to get screening if you have had a new partner. Chlamydia can be tested using a swab from the vagina or a urine sample, depending on the type of sex you have, a throat or rectal swab may also be recommended.

    If you are aged between 15 and 24 it's a good idea to take part in the national chlamydia screening program. Anyone can get a free test kit through their GP surgery, local sexual health or contraception clinic.

    You can purchase a chlamydia test that can be done at home using our Online Doctor service. If you test positive and if it's safe to prescribe antibiotics for you, we will prescribe treatment for you at no extra charge.

    When should you get tested for chlamydia?

    If you’ve had unprotected sex or you think you might have been exposed to chlamydia or other STIs you should get tested as soon as possible. However, if it’s been less than two weeks since the episode of unprotected sex, you can still test but you may be asked to repeat the test two weeks after the episode of unprotected sex to rule out chlamydia infection.

    You should regularly screen for STIs. For those at high risk, testing every three months is recommended. You can assess your risk of STIs using our free assessment. Remember that chlamydia does not always come with symptoms so even if you feel completely healthy you may still be infected.

    If you don’t have symptoms, you can order a discreet and easy-to-use home test kit for chlamydia for men, women, men who have sex with men, non- binary or trans people from LloydsPharmacy Online Doctor.

    Chlamydia treatment

    Treating chlamydia is usually straightforward with a 7 day course of antibiotics.

    Should your partner also be treated? 

    It should be noted that if you do test positive for chlamydia, your partner needs to take treatment as well. A test is usually recommended to confirm and check for other infections. But because chlamydia is very infectious, it makes sense to get them to start treatment straight away. You should not have sex until you and any partners have completed the treatment.

    Tests and treatments are all available from our Online Doctor service.


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