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Chlamydia trachomatis

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What is chlamydia?

Chlamydia trachomatis, known as Chlamydia, is one of the most common sexually transmitted infections (STIs). It affects both men and women and is especially prevalent in young adults or sexually active teenagers. In order to enjoy a healthy sex life and protect yourself and partners it is important to get regularly checked by your GP or a nurse at a sexual health clinic.

It is also wise to be aware of the types of sexually transmitted infections and diseases that can be contracted, and how these can be passed between sexual partners. It is advised that you are tested once a year or whenever you change sexual partners, as well as practising safe sex by using condoms.

What causes chlamydia?

Chlamydia is caused by the bacterium chlamydia trachomatis. The bacterium infects the cervix, urethra and rectum as well as non-genital areas such as the eyes and lungs. The bacteria are usually spread through unprotected sex or contact with infected genital fluids including semen and vaginal fluid.

How can you catch chlamydia?

  • Through unprotected vaginal, oral or anal sex with someone who has the infection
  • Infected semen or vaginal fluids getting into your eye
  • Sharing sex toys that have not been washed or covered with a new condom every time they are used
  • Your genitals touching someone else’s genitals even if there is no penetration, orgasm or ejaculation

Pregnant women can also pass the infection to their baby during childbirth, which means that their baby could develop an eye infection such as conjunctivitis or a lung infection like pneumonia.

You can’t contract chlamydia through:

  • Kissing or hugging
  • Sharing baths or towels
  • Swimming in your local leisure centre pool
  • Toilet seats
  • Cutlery


Most people who have chlamydia do not have any symptoms and do not know that they have the infection. If symptoms do appear these can take anywhere between a few weeks to a few months to become noticeable. Therefore many people may not use protection when having vaginal, anal or oral sex, and so give the infection to multiple partners.

Sometimes the symptoms can disappear after a few days, however just because they are no longer noticeable does not mean that the infection has gone, and you are still able to pass this on to your sexual partners. Visit this page to find out more about the symptoms that occur in men and women.


If untreated, chlamydia can lead to serious complications for both men and women. For women, these can include pelvic inflammatory disease (PID) which affects fertility, as well as increasing the risk of ectopic pregnancies and chronic pelvic pain. In men the infection can spread to the testicles and epididymis tubes, causing them to become swollen and painful, if this is not treated it can lead to fertility issues in the future.

Chlamydia is also the most frequent cause of sexually acquired reactive arthiritus. It can affect women who have had the infection but it is more common in men. The joints, eyes and uretha become painfully inflamed and swollen; this tends to happen within the first weeks of the person contracting the STI.

At this time there is no cure for reactive arthritis, and the symptoms should improve within a few months by themselves. Although treating the infection with anti-inflammatory medicines such as ibuprofen can help to relieve symptoms and pain.

Diagnosis and testing

Testing for chlamydia is done with a urine sample or a swab test, both of which can be down confidentiality at a health clinic, your GP surgery, genitourinary medicine (GUM) clinic or at home. You can get an at home chlamydia test kit from LloydsPharmacy or through a service like Online Doctor, where the test for chlamydia is typically combined with gonorrhoea. Commonly people who have one of these infections tend to have the other. Men can complete a urine sample and women can take a vaginal swab, both of these can then be sent to a partner laboratory for free. Your results will be sent to you and then you can decide where the best place for you to receive treatment is, whether at your doctors or a clinic.

Chlamydia is either treated with a one day course of antibiotic treatment or a longer course of tablets for a week. It is advised that after the course of antibiotics you should have another STI test carried out to make sure that the infection has cleared. You should avoid having sex for a week after receiving the treatment.

Is chlamydia curable?

Yes it is, however if you have had Chlamydia in the past and it was treated with a course of antibiotics, you can still catch the STI again in the future. In other words treatment for chlamydia does not make you immune to the infection. It is still important that you look after your own and your partner’s sexual health, by using male and female condoms and getting regularly tested.

How can I treat chlamydia?

Chlamydia is treated with a course of antibiotic tablets. Azithromycin is given as two or four tablets at once, and doxycycline is given as two capsules a day for one week.

How can I prevent catching chlamydia?

Using a condom during sexual intercourse or contact is the most effective method of protection.