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Overview

What Is Chlamydia?

Chlamydia is a common sexually transmitted infection caused by the bacterium Chlamydia trachomatis. It can affect the cervix, urethra, rectum, throat or eyes. Anyone who has sexual contact can develop chlamydia, regardless of sex or gender. Because it often causes no symptoms, a person may have and pass it on without knowing it.

Symptoms

Chlamydia Symptoms

Chlamydia frequently causes no noticeable symptoms. When symptoms do occur, they may begin several weeks after exposure or may not appear at all, so testing is important even when you feel well.

  • Pain or burning when urinating
  • Unusual vaginal discharge
  • Bleeding between periods
  • Bleeding after sex
  • Lower abdominal or pelvic pain
  • Pain during sex
  • Pain or burning when urinating
  • Discharge from the penis
  • Pain or swelling in a testicle
  • Rectal pain or discharge (proctitis)
  • Rectal bleeding
  • Sore throat after oral exposure

How It Spreads

How Chlamydia Spreads

Chlamydia spreads through vaginal, anal or oral sex when infected genital fluids or mucous membranes come into contact with another person. It can be passed on even when the infected person has no symptoms. Understanding how do you get chlamydia can help you choose testing and safer-sex measures.

  • Oral sex: Chlamydia can spread through oral sex involving an infected throat, penis, vagina or rectum.
  • Kissing: Ordinary kissing does not spread chlamydia because the infection is not passed through saliva.
  • Shared sex toys: Sharing sex toys without washing them or using a new condom on each toy can transmit the infection.
  • Pregnancy or childbirth: A pregnant person can pass chlamydia to a baby during childbirth, potentially causing eye or lung infection.
  • Casual contact: Hugging, sharing food, toilet seats or swimming pools does not spread chlamydia.

Risk Factors

Chlamydia Risk Factors

  • Age under 25 is a non-modifiable factor associated with a higher chance of chlamydia, particularly among sexually active people.
  • Having a new sexual partner is a modifiable relationship or exposure factor that may increase the need for testing.
  • Having multiple sexual partners can increase the chance of contact with an untreated infection.
  • Having a partner with an STI or a partner whose testing status is unknown can increase exposure risk.
  • Using condoms or dental dams inconsistently can increase the chance of transmission.
  • A previous episode of chlamydia or another STI increases the importance of future prevention and testing.
  • Pregnancy does not cause chlamydia, but it makes timely testing and treatment especially important.

Complications

Chlamydia Complications

Prompt treatment usually prevents complications, but untreated chlamydia can spread and damage reproductive organs. Some complications can occur even when symptoms are mild or absent.

  • Pelvic inflammatory disease can affect the uterus, fallopian tubes and ovaries.
  • Infertility can result from damage and scarring in the reproductive tract.
  • Ectopic pregnancy may occur when scarring prevents a fertilized egg from reaching the uterus normally.
  • Epididymitis can cause inflammation and pain in the tube behind a testicle and may affect fertility.
  • Reactive arthritis can cause joint, eye or urinary symptoms after an infection.
  • During pregnancy, untreated infection may contribute to pregnancy or newborn health complications.
  • A newborn exposed during childbirth may develop an eye infection or pneumonia.

Diagnosis

How Chlamydia Is Diagnosed

A healthcare professional diagnoses chlamydia with a laboratory test, not by appearance or symptoms alone. Testing usually looks for the infection in a urine sample or a swab from the body site that may have been exposed.

Sample or testWhen it may be used
Urine testingOften used to test for genital infection, especially when a person has a penis.
Vaginal or cervical swabMay be used to test for infection in the vagina or cervix and can often be collected by a clinician or, where available, by self-swab.
Urethral swabMay be considered when urethral symptoms are present or when a clinician needs a sample from the urethra.
Rectal swabUsed when there has been anal exposure or when rectal symptoms suggest possible infection.
Throat swabMay be used when oral exposure or throat symptoms make infection at that site a concern.

Treatment & Management

Chlamydia Treatment and Management

Chlamydia is curable with prescription antibiotics. The specific chlamydia medication and treatment duration depend on factors such as pregnancy, the infection site, allergies and current clinical guidance. Do not treat yourself without medical advice.

  • Take the full antibiotic prescription exactly as directed, even if symptoms improve sooner.
  • Avoid vaginal, anal and oral sex until your clinician says treatment is complete and partners have been treated as advised.
  • Make sure recent sexual partners are told, evaluated and treated to reduce reinfection.
  • Return for a chlamydia test or follow-up testing when your clinician recommends it.

USE ANTIBIOTICS SAFELY

Follow the prescribed treatment plan

Do not share antibiotics or use leftover medicine, because the drug or dose may be inappropriate and the infection may not be fully treated. Seek prompt clinical review for persistent symptoms, pelvic or testicular pain, fever or pregnancy-related concerns.

Prevention & Screening

Chlamydia Prevention and Screening

  • Use condoms or dental dams correctly during vaginal, anal and oral sex to reduce transmission risk.
  • Limit sexual exposure to partners who have been tested and treated when needed.
  • Consider testing before starting a new sexual relationship when appropriate for your circumstances.
  • Complete treatment and make sure recent partners receive evaluation and treatment to prevent reinfection.
  • Do not share sex toys, or wash them and use a new condom on each toy between users.

Who should discuss routine chlamydia screening?

Annual screening is commonly recommended for sexually active women under 25 and for older women with risk factors. Testing during pregnancy and repeat testing after treatment should follow clinician advice and local recommendations. Screening may also be appropriate for men and other people based on sexual exposure, symptoms or individual risk, so ask a healthcare professional when to check chlamydia.

Outlook and Prognosis

Outlook and Prognosis for Chlamydia

Chlamydia is generally curable with appropriate antibiotics, and symptoms should improve after treatment. However, untreated infection can cause permanent complications even when symptoms are mild or absent. Treatment cures the current infection but does not provide immunity, so a person can become infected again.

When Should You See a Doctor

When Should You See a Doctor for Chlamydia?

  • Arrange testing if you have possible chlamydia symptoms, even if they are mild.
  • Seek medical advice if a current or recent sexual partner has tested positive.
  • Arrange a chlamydia test after sex without a barrier with a new or multiple partner when exposure is a concern.
  • Seek confidential medical support and testing after sexual assault.
  • Discuss routine screening if you are sexually active and meet age, pregnancy or other risk-based recommendations.

SEEK PROMPT CARE

Some symptoms need timely evaluation

Seek prompt or urgent care for severe pelvic or testicular pain, fever or vomiting. If you are pregnant and may have been exposed, contact a healthcare professional promptly; seek urgent care for a newborn with eye or breathing symptoms.

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