What is chlamydia?

Chlamydia is a sexually transmitted infection (STI). You can catch it by having unprotected sex. Chlamydia is caused by a bacterium called chlamydia trachomatis.

Chlamydia is the most frequently reported infectious disease in Australia. In 2021, nearly 86,000 people were diagnosed with it. If you are sexually active and younger than 30 years old, you are at the highest risk of catching chlamydia.

Chlamydia can infect your:

• cervix
• urethra
• testicles
• mouth and throat
• anus
• eyes

What are the symptoms of chlamydia?

In females, chlamydia can cause the following symptoms

• change in your vaginal discharge
• bleeding or spotting between periods or after sex
• burning or stinging when urinating
• pain during sex
• cramps or pain in your lower stomach

In males, chlamydia can cause the following symptoms::

• clear or 'milky' discharge from your penis
• redness at the opening of your penis
• burning or stinging when urinating
• pain or swelling in one or both of your testicles

Most people who have chlamydia do not have any symptoms. This means you or your partner can be infected for months or years without knowing.

If you do get symptoms, they usually appear 2 – 14 days after you have had unprotected sex.

How do I get chlamydia?

You can get chlamydia from unprotected sexual contact with someone who already has it. Unprotected sexual contact means having vaginal, oral or anal sex without using a condom.

A newborn baby can get chlamydia from their mother during childbirth.

You cannot get chlamydia from toilets, swimming pools, spas or everyday contact with people.

When should I see my doctor?

You should see your doctor, visit a family planning clinic or a sexual health clinic if you:

• are concerned that you have an STI, even if you do not have any symptoms
• have had sexual contact with someone who has an STI

It's a good idea to avoid sex until you get medical advice.

If you are younger than 30 years old and sexually active, it's recommended to get checked for chlamydia and other STIs once a year.

For males who have sex with males, screening for chlamydia every 12 months is recommended.

Depending on your situation, your doctor may recommend more frequent screening. If you have any questions, check with your doctor or sexual health clinic.

How is chlamydia diagnosed?

Your doctor can diagnose chlamydia by sending a sample of your urine or a swab from your vagina cervix, anus or throat to a laboratory.

It is easy to collect the swab or sample. You can do it yourself (self-collected) or your health professional can help you.

Chlamydia and gonorrhoea testing is usually done together, as many people are infected with both. It is also a good idea to be tested for other STIs at the same time.

You cannot test for chlamydia with a blood test.

You can also be screened for chlamydia while getting other check-ups. For example, you can have a chlamydia screening while getting a cervical screening test.

Chlamydia is a nationally notifiable disease in Australia. This means that government health authorities must be told about all cases of chlamydia. This is done so that infections can be tracked. It is important to try stop outbreaks, because chlamydia can cause long-term health complications.

How is chlamydia treated?

Chlamydia is treated with antibiotics such as doxycycline or azithromycin. Usually, one dose is needed. If you develop a secondary infection, you may need to take antibiotics for longer.

Your sexual partners will also need to be treated. If you are worried they will not seek treatment themselves, you can get them an antibiotics prescription yourself. This is called patient delivered partner therapy (PDPT).

You are also recommended to:

• avoid sex, even with a condom, until 7 days after you have started antibiotics, or until you have finished treatment and symptoms have gone — whichever is later
• avoid sex with any partners from the past 6 months until they have been tested and treated
• test again for chlamydia 3 months after you have finished treatment, to make sure you have not been reinfected

Remember, after you finish your treatment, you are not immune to chlamydia. You can catch it again.

If you have chlamydia and do not get treated, you can develop painful and serious complications.

Can I prevent chlamydia?

You can lower your risk of getting chlamydia and other STIs by:

• using a condom every time you have vaginal, oral or anal sex
• not having sex with someone with chlamydia, even with a condom, until one week after their last dose of antibiotics

Remember that most people with chlamydia do not have any symptoms. They will not know they have it. Feeling 'well' does not mean that you or your partner are not infected. If in doubt, get tested.

Contact tracing

If you have chlamydia, you should tell all your sexual partners. That way they can also get tested and treated if needed. This helps to stop spreading the infection. Your doctor can help you decide who needs to be told.

Complications of chlamydia

If you have chlamydia and do not get treated, you can develop complications including:

• arthritis (joint inflammation)
• conjunctivitis and uveitis (eye inflammation)
• proctitis (inflammation of your rectum)
• infertility
• pelvic inflammatory disease (PID), ectopic pregnancies, miscarriages or premature birth
• epididymitis, urethritis (the tube that carries urine from your bladder to outside your body becomes inflamed)

If you have chlamydia during pregnancy, your baby can catch chlamydia and develop an eye or lung infection.

You can read more about chlamydia and pregnancy here.

Coping with my diagnosis

Finding out you have chlamydia can be distressing. You might feel alone, embarrassed, anxious and afraid of rejection or not being sexually desirable.

Chlamydia is a very common STI. It can be easily treated and you can fully recover.

If you are worried about telling recent sexual partners that you have chlamydia, you can send them an anonymous text message or email through some websites, such as Let Them Know.

Remember, your diagnosis is confidential. Your health professional is not allowed to tell anyone without your permission.

However, you may find it helpful to talk to a parent or a friend you trust. There are organisations that can support you, such as Sexual Health Quarters. They can provide counselling, help you with your treatments and answer questions you may have.

Resources and support

For more information and support, try these resources:

• NSW Sexual Health Infolink (1800 451 624; weekdays 9am to 5.30pm) is a non-judgemental information and STI referral service in New South Wales.
• Family Planning provides sexual health and reproductive services, including STI testing. Get information and find clinics in your state or territory here.
• The Let Them Know website helps you send free, anonymous text messages or emails to sexual partners to help with contact tracing.
• Drama Down Under is a website specifically for men with male sexual partners. Learn more about STIs, contact tracing and receive reminders when it's time to be retested.
• Learn more about the HPV vaccine on the Cancer Council HPV Vaccine webpage.

Other languages

The Melbourne Sexual Health Centre has fact sheets on chlamydia and other STIs in Chinese, Korean and Thai.