What is chlamydia?

A photo of Naveen Puri
Medical Director, Bupa UK Insurance
01 December 2021
Next review due December 2024

Chlamydia is one of the most common sexually transmitted infections (STIs) in the UK. Anybody who is sexually active (has sex) can get it. But it’s more common in people under the age of 25 than in older people. Here, I’ll answer some very common questions about chlamydia.

a couple holding hands

What are the symptoms of chlamydia?

Most people who have chlamydia don’t have any signs or symptoms. So, you might have the infection and pass it on to somebody you have sex with without knowing. If you do get symptoms, they can appear up to three weeks after you get the infection. You may have:

  • cloudy white, yellow or green discharge from your vagina, penis, or anus
  • vaginal, testicular or tummy pain
  • vaginal bleeding between periods or after sex
  • pain when you pee or when you have sex
  • a sore throat (if the infection has been passed on during oral sex)


If you have a chlamydia infection in your rectum (back passage), you might notice some discomfort and discharge from your anus. But usually, you won’t have any symptoms. If your eyes are infected (conjunctivitis) you might have some mild irritation, pain and swelling.

If you think you could have a sexually transmitted infection (STI), you should get tested.

How serious is chlamydia?

Chlamydia is usually easily treated with antibiotics. If you get tested and treated for chlamydia early, it’s less likely to cause you further problems.

But, if it isn’t treated the infection can spread to your womb (uterus), fallopian tubes and ovaries. This can cause more serious problems, including pelvic inflammatory disease (PID) and infertility.

Chlamydia can also lead to permanent rectal damage (damage to the back passage) in people with an STI called lymphogranuloma venereum (LGV). In recent years, most LGV infections have been in the rectum (back passage). They are usually caused from having anal sex without condoms. It can cause painful inflammation of the rectum. You can also get a discharge and swollen lymph glands (lymph nodes).

That’s why it’s important to have any chlamydia infection treated with antibiotics.

What causes chlamydia?

Chlamydia is caused by a type of bacterial infection. You can get or pass on chlamydia through having unprotected vaginal, anal, or oral sex with an infected person. It can also be passed on by sharing sex toys.

The bacteria can’t survive outside the body for long. You don’t get chlamydia from kissing, hugging or sharing baths, towels or cutlery. You also won’t get it from swimming pools or toilet seats.

When should you get tested for chlamydia?

If you think you might have chlamydia, do not delay being tested. You should arrange to have a test if:

  • you, or a person you’ve had sex with, has any of the symptoms listed in the symptoms section above
  • you’ve recently had unprotected sex (sex without a condom) with somebody new
  • somebody you’ve had sex with has had unprotected sex with another person
  • somebody you’ve had sex with recently tells you they have a sexually transmitted infection
  • you’ve had sex with two or more people in the last year


You can have a test even if you don’t have any symptoms.

How do you get tested for chlamydia?

Testing for chlamydia is done with a swab test or urine test. If you’re sexually active and under the age of 25, it’s recommended that you have a chlamydia test at least once a year. In England, the tests are offered free to all people under the age of 25. There are a number of services where you can get tested for chlamydia and other STIs for free, and straight away. These include:

  • genitourinary medicine (GUM) and sexual health clinics
  • your GP surgery
  • contraception clinics and some pharmacies


You can also pay to get a test done at a private clinic. All visits are confidential and your details won’t be sent to your GP without your consent. Chlamydia testing kits can be bought to do at home as well.

If the tests show that you have chlamydia, it's important to inform anybody you’ve recently had sex with. This could be anyone you’ve had sex with in the past six months. Your clinic will advise you.

How is chlamydia treated?

Chlamydia is usually easily treated with oral antibiotics (antibiotics you take as tablets). Your doctor might prescribe a course of an antibiotic called doxycycline that you’ll need to take for a week. Sometimes, other antibiotics are used instead. This will depend on the type of chlamydia infection you have, and which antibiotic will provide the best treatment.

Telling others

If somebody you’ve had sex with has been diagnosed with chlamydia, you’ll be offered treatment even if you haven’t had your test results back yet. If you’re diagnosed with chlamydia, you shouldn’t have sex again until you and the person you’re having sex with have finished treatment. Check with your doctor when exactly this should be.

The time can vary depending on which type of antibiotic treatment you have.

Can I reduce my risk of getting or passing on chlamydia?

There are many things you can do to lower your risk of getting or passing on chlamydia, as well as other sexually transmitted infections.

  • If you have a penis, use a condom whenever you have vaginal, oral or anal sex.
  • A latex square (dental dam) can also be used to cover the anus and vaginal opening, including the area around it.
  • Don’t share sex toys. If you do, wash them well or cover them with a new condom before anyone else uses them.


Before you have unprotected sex with somebody new, have a test for chlamydia and other STIs. This will also help to prevent the spread of chlamydia.

We offer a range of sexual health services within our Bupa Health Centres. So whether you have symptoms and need to speak to a GP or don't have symptoms but want a check to see if you currently have an STI we have a check to suit you. Any customers who test positive receive a follow up with a GP and support from our 24/7 Nurse HealthLine. Learn more today.

A photo of Naveen Puri
Dr Naveen Puri
Medical Director, Bupa UK Insurance

    • Sexually transmitted infections and screening for chlamydia in England, 2018. Health Protection Report. Public Health England. GOV.UK., accessed November 2021
    • Overview of sexually transmitted infections. BMJ Best Practice., last updated December 2020
    • Genital tract chlamydia infection. BMJ Best Practice., last reviewed June 2019
    • Nwokolo NC, Dragovic B, Patel S, et al. 2015 UK national guideline for the management of infection with Chlamydia trachomatis. Int J STD AIDS 2016; 27(4): 251–67. doi:10.1177/0956462415615443
    • Health Matters: Preventing STIs UK Health Security Agency., published August 2019
    • Update on the treatment of Chlamydia trachomatis (CT) infection. BASHH clinical effectiveness group., published September 2018
    • Chlamydia – uncomplicated genital. NICE Clinical Knowledge Summaries., last revised June 2019
    • Chlamydia. Family Planning Association., published December 2019
    • LGV (lymphogranuloma venereum). Terrence Higgins Trust., last reviewed September 2018
    • Chlamydia genital infection. Patient., accessed November 2021
    • Update on the treatment of Chlamydia trachomatis (CT) infection. BASHH clinical effectiveness group. , published September 2018
    • Chlamydia – CDC Fact Sheet. Centers for Disease Control and Prevention., accessed November 2021

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