Patient information from BMJ

Chlamydia

Last published:Oct 11, 2021

Chlamydia is an infection that is passed from person to person during sex. It is easily treated. But if it isn't detected and treated it can cause serious health problems. Practising safe sex can help you to avoid getting it.

We've brought together the best and most up-to-date research about chlamydia to see what treatments work. You can use our information to talk to your doctor and decide which treatments are best for you.

What happens in chlamydia?

Chlamydia is an infection caused by bacteria called Chlamydia trachomatis. You can catch chlamydia if you have sex with an infected person.

• If you're a man it can affect the tube that carries urine down from your bladder to the outside (the urethra). And it can sometimes affect the prostate.

• If you're a woman it can affect the neck of your womb (cervix) or your urethra, or both. It can sometimes also lead to other problems including pelvic inflammatory disease (PID), a more widespread infection of the reproductive organs.

• The infection can be passed on by oral sex and anal sex as well as by vaginal sex. So it can also affect your throat and your rectum.

• If you touch your eye after touching infected fluid from your genitals you can get an eye infection.

Newborn babies also can be affected by chlamydia. This is because women who have the infection can pass it on during childbirth. If you're pregnant and you have chlamydia your baby may be born with eye infection or pneumonia. Both of these problems can be treated with antibiotics.

What are the symptoms?

Chlamydia is sometimes called the 'silent disease' because you can have it without knowing it. Many people who have chlamydia don't have any obvious signs of infection.

If you do get symptoms, you may get these if you're a woman:

• Unusual discharge from your vagina

• Bleeding between periods

• Pain when passing urine

• Pain in your lower abdomen.

If you're a man you might get:

• Discharge from your penis

• Burning and itching around your genitals

• Pain when passing urine.

How do doctors diagnose it?

If you get symptoms like those listed above you should visit your doctor or your local sexual health clinic. A sample of your urine or a swab will be tested for the infection.

If you're a woman the swab will be taken from your cervix. If you're a man the swab will be taken from the tube that carries urine down from your bladder (urethra). If you might have an infection in your throat or your rectum you'll probably also have a throat swab or a rectal swab taken.

If the test shows you have chlamydia your last sex partner, and any other partners you've had within the past few months, should be tested for chlamydia too.

Screening for chlamydia

Many countries now have national screening programmes for chlamydia for people considered at high risk of infection. For example, in the UK, testing is offered to sexually active people under 25 years of age. This is considered important because many people have chlamydia without knowing it.

What treatments work?

If you have chlamydia, treatment with antibiotics can get rid of the infection. Antibiotics are medicines that kill bacteria.

It's important not to have sex until you and your partner have finished your course of antibiotics. With some antibiotics you may have to wait longer until you can have sex. Your doctor will explain which antibiotics you are prescribed and what you need to do to make sure they work best.

Antibiotics don't usually cause serious side effects. But after taking them some people feel sick, or get an upset stomach, stomach pain, or diarrhoea.

If you're a pregnant woman

Some antibiotics are not considered safe to use during pregnancy. But there are others that you can take. Your doctor will advise you about safe treatment for chlamydia during pregnancy.

It's possible that taking antibiotics while pregnant might not prevent the infection in your baby, even if they seem to clear up your infection.

What will happen to me?

Chlamydia is usually easy to treat with simple antibiotic tablets. But if it isn't recognised and treated, chlamydia can spread. This can have serious effects on your health. Many people feel embarrassed about visiting their doctor about a sexual issue or about going to a sexual health clinic. But doctors and clinic staff deal with these problems every day, and they are there to help you.

So if you think you have chlamydia or any sexually transmitted infection, see your doctor or visit your local sexual health clinic as soon as possible.

If you're a woman

Chlamydia that isn't treated can spread to your ovaries, your womb, or the tubes that lead from your ovaries to your womb (the fallopian tubes). When this happens it's called pelvic inflammatory disease (PID).

Pelvic inflammatory disease can lead to blocked fallopian tubes, which can make it hard for you to get pregnant. It can also cause an ectopic pregnancy. In an ectopic pregnancy a fertilised egg starts growing in the fallopian tube.

Ectopic pregnancies are dangerous for the mother. The egg cannot develop into a baby and usually has to be removed, either using drugs that end the pregnancy or with an operation.

If you're a man

Chlamydia that isn't treated can lead to inflammation in the tubes leading to your testicles or in the testicles.

You can also get a form of arthritis known as reactive arthritis.

What can I do to stop getting chlamydia again?

The best way to reduce your risk of getting infected with chlamydia again is to:

• Use condoms when having sex, and make sure you're using them correctly

• Get tested for chlamydia regularly.

Some people choose to be tested when starting a new relationship. They may also ask their partner to be tested.