Chlamydia: testing, treatment, partner notification and complications

The NHS describes chlamydia as a sexually transmitted infection (STI) that is often passed on through unprotected sex, treated with antibiotics, and capable of causing serious health problems if untreated. Terrence Higgins Trust says it is caused by bacteria found in infected semen and vaginal fluids.

According to the NHS it is spread through vaginal fluid and semen, and can pass from person to person through vaginal, oral or anal sex without a condom, or through fluid on sex toys and hands. If you have chlamydia while pregnant, it can pass to the baby during birth. Terrence Higgins Trust adds that infected semen or vaginal fluid getting into the eye can also pass it on.

Most people have no symptoms, the NHS says. Where they occur, the NHS lists the following.

• In people with a vagina: vaginal discharge that is not normal for you, bleeding after sex or between periods, a burning feeling when you pee, and pain in the lower tummy.

• In people with a penis: white, cloudy or watery discharge from the tip of the penis, burning and itching around the testicles and penis, pain and swelling in the testicles, and burning when you pee.

• Elsewhere: pain, bleeding and discharge from the bottom, a sore throat, and eye redness, pain and discharge.

The NHS says you can be tested even if you have no symptoms. A doctor or nurse asks about symptoms and sexual partners and may need to check the penis or vagina. You may be asked for a urine sample, or a swab, like a cotton bud, may be used to take fluid from the penis or vagina, and you may be able to take the swab yourself. Swabs from the bottom, throat or eyes may be needed if those areas are affected. You may also be offered tests for other STIs at the same time, and you can ask for a chaperone when you book.

If you do not have symptoms but want a test, the NHS says you can use a self-test kit at home and send it to a lab; you will be contacted if it is positive. Free kits may be available from sexual health clinics and some pharmacies, and under-25s may be able to get free home kits. Terrence Higgins Trust describes the tests as simple and painless, with swabs taking only a few seconds, and says most people are tested at sexual health or GUM clinics, which are free and confidential, although some GP surgeries also test and treat.

The NHS advises going to a sexual health clinic or GP if you or a partner think you might have chlamydia, if you have had sex without a condom, or if you are pregnant or planning pregnancy and think you might have it.

The NHS says chlamydia is treated with antibiotics, either a single dose or tablets taken for 7 to 14 days, and that treatment may sometimes start before test results come back. You may need to be retested after treatment to check the infection has gone, and if you are pregnant you are tested again 4 weeks after treatment. Terrence Higgins Trust says the most common treatments are a single dose of azithromycin or a week-long course of doxycycline, and that antibiotics can be taken while pregnant or breastfeeding without harming the baby, although it is best to tell the doctor or nurse. The choice of antibiotic is the prescriber's.

Both sources are clear about sex. The NHS says to avoid vaginal, anal or oral sex until you and your partner have finished treatment and tests show you no longer have chlamydia. Terrence Higgins Trust says to wait 7 days after treatment has finished, even after a single dose, and notes that you could pass on the infection even with a condom if you have sex before treatment has finished.

The NHS says if you have chlamydia your current and recent sexual partners need to be tested, and a sexual health clinic can help you contact them or contact them for you. Terrence Higgins Trust makes the same point and says a clinic can contact partners if you do not want to.

The NHS lists infection of the womb, fallopian tubes and ovaries (pelvic inflammatory disease), which can lead to infertility or ectopic pregnancy; infection in the testicles; and joint pain from reactive arthritis, which usually gets better after a few months. It says the sooner you get treatment, the easier these complications are to treat.

In pregnancy, untreated chlamydia can be passed to the baby at birth and cause an eye infection (conjunctivitis) or a lung infection (pneumonia), both treatable with antibiotics, according to the NHS. Terrence Higgins Trust says it is not passed on in breastmilk and that a test is likely to be offered as part of antenatal care.

The NHS suggests:

• using condoms for vaginal or anal sex

• using a condom over the penis, or a latex or plastic square (dam) over the vagina, for oral sex

• getting tested once a year, or when you have a new sexual partner

• completing the full course of treatment if you or a partner have chlamydia

• not sharing sex toys, or washing them and covering them with a new condom before anyone else uses them