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InfectiousICD-10: A56.2About 1.8 million reported cases annually in the U.S.

Chlamydia

Also known as: Chlamydial Infection, Chlamydia trachomatis Infection

Chlamydia is the most commonly reported sexually transmitted infection (STI) in the United States, caused by the bacterium Chlamydia trachomatis. It often has no symptoms, which means it can be unknowingly transmitted to sexual partners. If left untreated, chlamydia can cause serious reproductive health complications including pelvic inflammatory disease and infertility.

Symptoms

Often asymptomatic (up to 70% of women and 50% of men have no symptoms)
Abnormal vaginal or penile discharge
Burning or pain during urination
Pain during sexual intercourse (women)
Testicular pain or swelling (men)
Lower abdominal or pelvic pain
Bleeding between periods or after sex (women)
Rectal pain, discharge, or bleeding (with rectal infection)

Causes

  • Infection with the bacterium Chlamydia trachomatis
  • Transmitted through vaginal, anal, or oral sexual contact
  • Can be passed from mother to infant during vaginal delivery

Risk Factors

  • Sexually active individuals under age 25
  • Multiple sexual partners
  • Not using condoms consistently
  • History of prior STIs
  • Having a partner with an STI

Diagnosis

  • Nucleic acid amplification test (NAAT) on urine or swab sample
  • Vaginal or cervical swab in women
  • Urethral swab or first-void urine in men
  • Rectal or pharyngeal swab if indicated

Treatment

  • Doxycycline (preferred first-line treatment)
  • Azithromycin (single-dose alternative)
  • Partner notification and treatment to prevent reinfection
  • Abstain from sexual activity for 7 days after treatment completion
  • Test of cure in 4 weeks for pregnant women
  • Retest 3 months after treatment to check for reinfection

Prevention

  • Use condoms consistently and correctly during sexual activity
  • Get screened annually if sexually active and under 25
  • Limit number of sexual partners
  • Ensure sexual partners are tested and treated

When to See a Doctor

  • You experience abnormal genital discharge or pain during urination
  • A sexual partner has been diagnosed with an STI
  • You are sexually active and have not been screened recently
  • You are pregnant and have not been tested for STIs

Frequently Asked Questions

Related Conditions

Cervical Cancer

Cancer

Conjunctivitis

Eye & Ear

Diverticulitis

Digestive

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