Chlamydia remains the most frequently diagnosed sexually transmitted infection in England, with over 150,000 cases reported annually according to the UK Health Security Agency (UKHSA). It is most prevalent among sexually active people aged 15 to 24.
How Is Chlamydia Diagnosed?
Diagnosis is straightforward. For women and people with vaginas, a self-collected vaginal swab is the most accurate method. For men and people with penises, a urine sample is typically used. Results from NHS or accredited labs are usually available within a few days.
Many people with chlamydia have no symptoms at all, which is why routine screening is so important. When symptoms do appear, they may include:
- Unusual discharge from the vagina, penis, or rectum
- Pain or burning during urination
- Pain during sex or bleeding after sex
- Lower abdominal pain
Treatment Options
Chlamydia is treated with antibiotics. Current BASHH (British Association for Sexual Health and HIV) guidelines recommend:
- Doxycycline 100 mg twice daily for 7 days – this is now the first-line treatment, replacing the previous single-dose azithromycin regimen
- Azithromycin 1 g single dose followed by 500 mg daily for two days – used as an alternative when doxycycline is not suitable
Note: The shift to doxycycline as first-line treatment reflects evidence of higher cure rates compared with single-dose azithromycin.
What Happens After Treatment?
BASHH guidelines recommend avoiding sexual contact for 7 days after starting treatment (or until both partners have completed the course). Your clinician will advise on follow-up — a test of cure is not routinely required, but may be recommended for pregnant individuals or where adherence is uncertain.
It is essential that all recent sexual partners are notified so they can also be tested and treated. Your clinic or GP can assist with partner notification, and anonymous notification services are available.
Risks of Untreated Chlamydia
Left untreated, chlamydia can lead to serious complications including pelvic inflammatory disease (PID), ectopic pregnancy, and reduced fertility in women. In men, it may cause epididymitis. Early treatment is simple, effective, and prevents long-term harm.