Chlamydia

Chlamydia is a sexually transmitted infection (STI) that is passed on from one infected person to another through unprotected sex. It is the commonest sexually transmitted bacterial infection in the UK and is most prevalent in under-25s.

Chlamydia typically causes inflammation of the lower urogenital tract. In men, it affects the urethra and in women, the urethra and/or the cervix.

It can also occur in the rectum through unprotected anal sex, the nasopharynx (upper throat behind the nose) through unprotected oral sex, and the conjunctiva (eye) if an infected person’s semen or vaginal fluid comes into contact with the eyes (Brook, 2022; National Institute for Health and Care Excellence (NICE), 2022).

When genital bacteria don’t spread to the upper urogenital tract, it is sometimes known as ‘uncomplicated’ chlamydia, and can usually be treated successfully if it is identified early.

Left untreated, chlamydia can cause pelvic inflammatory disease (PID) in women

Many people with chlamydia do not experience any noticeable symptoms: around 70-75% of women and 50% of men have asymptomatic infection (Brook, 2022; NICE, 2022b). When people have symptoms, they are very often mild and transient. Onset is typically between 7 and 21 days after unprotected sex with an infected partner, but symptoms can develop months afterwards (NHS, 2021).

In sexually active women, symptoms include:

• unusual vaginal discharge
• abnormal bleeding – after sex or between periods
• pain on urinating
• pain in the abdomen and/or pelvis
• pain during sex
• cervical motion tenderness and inflammation (identified on examination)

In sexually active men, symptoms include:

• pain on urinating
• unusual discharge from the penis
• burning sensation and pain in the urethra
• inflammation of the epididymis and/or testes (epididymo-orchitis)
• reactive arthritis

Following unprotected anal or oral sex with an infected partner, chlamydia can affect the rectum and cause soreness, discomfort and discharge from the back

The cause of chlamydia is the bacterium chlamydia trachomatis, which is found in the genital fluid of the bacteria’s host – semen in men and vaginal fluid in women. It is primarily spread through unprotected vaginal, anal or oral sex with an infected person, though it can also spread through sexual contact without penetrative sex having occurred.

For example, it can spread when a person’s genitals come into contact with those of an infected partner. Sharing sex toys without using a condom each time and without cleaning them after use can also spread the bacteria between partners (Brook, 2022).

It is unclear whether the chlamydia bacteria can be passed via the hands and fingers through touch.

Chlamydia is diagnosed through testing swabs. In women, the first-line test is a vaginal swab or alternatively, a cervical swab. If the patient does not want to undergo vaginal or cervical swab, they can instead opt to provide a urine sample.

Importantly, the urine must be a ‘first-catch’ rather than mid-stream sample, in order to collect the first drops (around 20ml) of urine released after it has been in the bladder for at least 1 hour (NICE, 2022c).

For men, a first-catch urine sample is the preferred test, followed by a urethral swab.

First-catch urine sampling kits are available for anyone to self-test, and vaginal swab self-test kits are available for women.

If rectal chlamydia is suspected and the patient has symptoms, a rectal swab should be taken. This can be done by the patient or by a clinician. If the person has inflammation of the rectal lining it is

The majority of people with uncomplicated genital chlamydia – around 95% of cases – can be successfully treated with antibiotics.

Antibiotics can be initiated if chlamydia is suspected or confirmed. Usually, the preferred option is doxycycline 100mg twice daily for 7 days, or a single dose of 1g of azithromycin followed by 500mg once daily for 2 days (NICE, 2022d).

Alternatives are available to treat pregnant or breastfeeding women, and those in whom the first-line treatments are contraindicated. If there is a risk of complications, the patient can be prescribed a longer course of antibiotics. Antibiotics should also be offered to anybody whose sexual partner tests positive for chlamydia (Brook, 2022).

It is crucial that whatever treatment is offered is completed in full. Patients should seek further advice if they are symptomatic, their symptoms do not improve within 7 days, and if they (Brook, 2022):

• have unprotected sex again, before

Anyone with suspected or confirmed chlamydia should be strongly advised to follow up with a genitourinary medicine (GUM) clinic, where they should also be screened for other STIs like gonorrhoea, syphilis, hepatitis B and HIV (NICE, 2022d).

It is also important that contract tracing is conducted, and that if chlamydia and/or other STIs are confirmed by a positive test, all current and recent sexual partners – within the last 6 months – are traced and managed. People should abstain from sex, and sexual contact where there is a risk of spread, for the duration of their treatment and for 7 days afterwards, to avoid passing the infection on and becoming reinfected themselves (Brook, 2022).

If a person under the age of 25 tests positive for chlamydia, the test should be repeated 3 to 6 months after they complete the course of treatment because they are at increased risk of reinfection

References

Brook Young People. Chlamydia. 2022. https://www.brook.org.uk/your-life/chlamydia/ (accessed 26 May 2022)

European Centre for Disease Prevention and Control. Chlamydia control in Europe: literature review. 2014. https://www.ecdc.europa.eu/sites/default/files/media/en/publications/Publications/chlamydia-control-europe.pdf (accessed 26 May 2022)

NHS. Symptoms – Chlamydia. 2021. https://www.nhs.uk/conditions/chlamydia/symptoms/ (accessed 26 May 2022)

NHS. Treatment – Chlamydia. 2021b. https://www.nhs.uk/conditions/chlamydia/treatment/ (accessed 26 May 2022)

NHS Inform. Lymphogranuloma venereum (LGV). 2022. https://www.nhsinform.scot/illnesses-and-conditions/sexual-and-reproductive/lymphogranuloma-venereum-lgv (accessed 26 May 2022)

National Institute for Health and Care Excellence. Chlamydia – uncomplicated genital: summary (CKS) 2022. https://cks.nice.org.uk/topics/chlamydia-uncomplicated-genital/ (accessed 26 May 2022)

National Institute for Health and Care Excellence. Chlamydia – uncomplicated genital: When should I suspect and test for chlamydia? (CKS) 2022b. https://cks.nice.org.uk/topics/chlamydia-uncomplicated-genital/diagnosis/signs-symptoms/ (accessed 26 May 2022)

National Institute for Health and Care Excellence. Chlamydia – uncomplicated genital: How should I test for chlamydia? (CKS) 2022c. https://cks.nice.org.uk/topics/chlamydia-uncomplicated-genital/diagnosis/testing-to-confirm-the-diagnosis/ (accessed 26 May 2022)

National Institute for Health and Care Excellence. Chlamydia – uncomplicated genital: Scenario: Management of uncomplicated genital chlamydia (CKS) 2022d. https://cks.nice.org.uk/topics/chlamydia-uncomplicated-genital/management/management/