Chlamydia

A common sexually transmitted bacterial infection that often has no symptoms but can affect fertility if untreated.

InfectionSexual healthLast updated: 21 October 2026

Quick Summary

Primary Symptoms

Often none. Discharge, pain passing urine, pelvic pain, bleeding after sex or between periods, and testicular pain.

Common Treatments

A short course of antibiotics such as doxycycline or azithromycin; partners should be treated.

Risk Factors

Unprotected sex, new or multiple partners, and age under 25.

OverviewSymptomsCausesTreatmentFAQ

Overview

Chlamydia is caused by Chlamydia trachomatis. Because it's often silent, testing is important for sexually active people at risk.

Untreated, it can cause pelvic inflammatory disease, ectopic pregnancy and infertility.

Symptoms

Often no symptoms

Especially in women.

Discharge

Unusual discharge.

Pain

Passing urine or in the pelvis.

Bleeding

After sex or between periods.

Causes & Risk Factors

Biological Causes

Infection with Chlamydia trachomatis through sexual contact.

Key Risk Factors

  • Unprotected sex Not using condoms.
  • Multiple partners Or a partner with other partners.
  • Previous STIs Increase risk.

Management & Treatment

01. Antibiotics

Doxycycline or azithromycin.

02. Partner treatment

Treat partners.

03. Retesting

As advised.

Frequently Asked Questions

Can it be cured?
Yes.
Can I have it without knowing?
Yes, which is why testing matters.

Sources and further reading

Last updated 21 October 2026. For more detail, see these trusted health organisations.