What Is Chlamydia?

STI

What Is Chlamydia?

Chlamydia is the most commonly diagnosed bacterial STI in the UK. It’s caused by the bacterium Chlamydia trachomatis and can infect the genitals, throat and rectum. Up to 70-80% of women and many men have no symptoms, which is why regular testing matters. Chlamydia is easily cured with a short course of antibiotics, and early treatment prevents complications like pelvic inflammatory disease and infertility.

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Key Facts

Symptoms

• Women: often silent; unusual discharge, bleeding between periods, pelvic pain
• Men: discharge from penis, burning on urination; sometimes silent
• Throat and rectum: almost always silent

Complications If Untreated

• Pelvic inflammatory disease (PID)
• Infertility
• Ectopic pregnancy
• Epididymitis in men
• Reactive arthritis
• Increased HIV susceptibility

Testing

• Urine sample or self-collected vaginal swab
• Home test kits free in many areas
• Include throat and rectal swabs if relevant
• Reliable from 1-2 weeks after exposure

Treatment

• Doxycycline 100mg twice daily for 7 days
• Avoid sex for 7 days after starting
• Partners tested and treated
• Retest 3 months later to catch reinfection

Prevention

• Condoms
• Regular testing (yearly under 25; more often with new partners)
• Partner treatment prevents reinfection

Read more: Home chlamydia tests | Chlamydia from oral sex | UK rates

Frequently Asked Questions

Can I have chlamydia without symptoms?

Yes — most people have none.

Is chlamydia curable?

Yes — easily with a 7-day course of doxycycline.

How often should I test?

Yearly if under 25; after each new partner; more often if at higher risk.

Related reading

• What Is Mycoplasma Genitalium?
• Can You Get Chlamydia From Kissing?
• Can You Have Chlamydia and Test Negative?
• How Common Is Chlamydia in the UK?
• Multi-Site STI Testing: Genital, Rectal and Throat

Sources

• NHS — Sexual health conditions
• BASHH — UK clinical guidelines for STI management
• British HIV Association (BHIVA) — HIV treatment guidelines
• Terrence Higgins Trust — sexual health information
• UK Health Security Agency — STI surveillance data

Steve Page

Steve Page is a recognised expert on Sexually Transmitted Diseases (STDs) and STD treatments, having published numerous articles in peer-reviewed journals and presented his research at conferences around the world. He has an in-depth understanding of the latest medical research on STDs, and is an advocate for the development of new treatments and protocols to improve the health of those affected. In addition to his research, he has dedicated his career to understanding the causes and symptoms of STDs, as well as how to best treat those impacted.