Last updated:

Reviewed by:

Dr Bryony Henderson

, Lead GP at Livi

Medically reviewed

Chlamydia is a bacterial infection that you can catch by having sex with an infected person. Read about the symptoms, testing, and treatment for chlamydia.

What is chlamydia?

Chlamydia is a sexually transmitted infection (STI) passed on by having sex with an infected person. It’s the most common bacterial STI in the UK, especially among teenagers and young adults. Chlamydia doesn’t usually cause symptoms, so it’s essential to have a test if you have unprotected sex with a new partner. Around 70% of women and 50% of men with chlamydia will be asymptomatic (have no symptoms). 

What causes chlamydia?

You can get chlamydia through:

  • Unprotected oral, anal or vaginal sex

  • Sharing sex toys that aren’t clean

  • Your genitals touching someone else’s – even without penetration

You can’t get infected with chlamydia by sharing cutlery, kissing on the lips, from swimming pools, toilet seats or by hugging.

What are the symptoms of chlamydia?

Most people who get chlamydia don’t have any symptoms, so they don’t know they have it. But some people do notice signs between 1 and 3 weeks, although they can take months to appear.

Possible chlamydia symptoms for women are: 

  • Unusual discharge

  • Pain when you pee

  • Tummy or pelvic pain 

  • Pain during sex

  • Bleeding after sex

  • Bleeding in between periods

Possible chlamydia symptoms for men are: 

  • White, watery or cloudy discharge from the penis

  • Pain when you pee

  • Burning or itching in the urethra

  • Swollen or painful testicles

If you get chlamydia from anal sex, you might experience pain in your rectum or notice a discharge. If you’re infected through oral sex, you might get a sore throat.

If infected semen or vaginal fluid gets into your eye, it may cause conjunctivitis. Symptoms include redness, soreness and sometimes a discharge. 

How is chlamydia diagnosed?

A chlamydia test involves giving a pee sample or having a swab taken. Talk to a GP to arrange a test. 

If you’re under 25, doctors recommend you have a chlamydia screening test once a year or whenever you have a new sexual partner. This is because, in most cases, there are no obvious symptoms, so you could have the infection without knowing it.

Having regular chlamydia tests means you can find out and treat the infection early and are less likely to have complications. You’ll also be less likely to spread it to other people.

How to treat chlamydia

Chlamydia treatment involves taking antibiotics, either a strong dose that you take all in 1 day or a course of tablets for a week.

It’s essential to finish the entire course of antibiotics and not have sex until you’ve completed the treatment. If you’re taking the one-day chlamydia treatment, you must not have sex for a week so you don’t pass the infection on. It’s also essential that your current sexual partner is treated so they don’t give the infection back to you once you’ve been treated. 

Chlamydia complications

If you don’t treat chlamydia, it can cause longer-term problems. 

For women, it can cause pelvic inflammatory disease (PID), and for men, it can cause swelling in the testicles. Both these can affect your fertility.

Untreated chlamydia can also lead to reactive arthritis, which can cause pain in your joints, eyes or urethra.

When should I seek help for chlamydia?

If you have any chlamydia symptoms, speak to a GP about having a test. You can also go to a sexual health clinic where you can have screening for other STIs too.

You should also get a chlamydia test if you haven’t got symptoms but also if:

  • You’ve had unprotected sex with a new partner

  • A sexual partner has told you they have an STI

  • Your partner has had unprotected sex with someone else

  • A condom has split during sex

If you’re pregnant or trying to conceive, you should also ask for a test as you can pass the infection to your unborn baby.

How to prevent chlamydia

Anyone sexually active can catch chlamydia. Your risk is higher if you have a new sexual partner or don’t use condoms.

The best way to reduce your risk of getting and spreading chlamydia is to have safe sex by: 

  • Using the right kind of condom for vaginal, oral and anal sex

  • Using a dental dam (a protective square of plastic) for oral sex 

  • Cleaning sex toys thoroughly (you may also want to consider placing a condom on sex toys)

Last updated:
Reviewed by:
Dr Bryony Henderson, Lead GP at Livi