Chlamydia: Symptoms, Causes, Treatment  and Prevention in Men and Women 

Introduction

Many people find sexual health difficult to talk about, but noticing symptoms and getting regular check-ups can protect your health. Chlamydia is a common sexually transmitted infection (STI) that often causes mild symptoms or no symptoms at all. If it is not treated, it can lead to health problems. This article explains what chlamydia is, how it spreads, possible symptoms, risk factors, complications, diagnosis, treatment, and ways to reduce your risk. 

What Is Chlamydia?

Chlamydia is a bacterial infection caused by Chlamydia trachomatis. It is one of the most common STIs and can be cured with antibiotics¹. It can affect both men and women². Chlamydia can spread through vaginal, anal, or oral sex with a person who has the infection. It can also pass from the mother to the baby during childbirth¹. Because many people have no symptoms, testing is the only reliable way to know if you have this infection. 

Symptoms of Chlamydia in Men and Women

Chlamydia infection often presents with no noticeable symptoms. When symptoms do appear, they may start about 1 to 3 weeks after exposure, although they can appear later. Symptoms may affect the genitals, rectum, throat, or eyes. Symptoms that can occur in anyone include¹:

• Rectal infection: pain, bleeding, or unusual discharge from the anus 
• Throat infection: often no symptoms, but a sore throat may occur 

Chlamydia symptoms in men

In men, chlamydia symptoms may involve the penis, urinary tract, or testicles. These symptoms can include: 

• Clear, white, cloudy, or yellow discharge from the penis 
• Pain or burning when passing urine 
• Pain or swelling in the testicles 

These symptoms can affect comfort, sexual health, and urinary health. Testing is important because many men have no symptoms. 

Chlamydia symptoms in women

In women, chlamydia can affect the urinary and reproductive systems. Symptoms can include: 

• Clear, white, or yellow discharge from the vagina 
• Burning sensation or pain during urination 
• Pain in the lower abdomen 
• Pain during sex 
• Bleeding between periods or after intercourse 

Causes of Chlamydia

Chlamydia is caused by the bacterium Chlamydia trachomatis. It spreads when a person has sexual contact with someone who has the infection. Common routes include³: 

• Vaginal sex with an infected person 
• Anal sex with an infected person 
• Oral sex with an infected person 
• Passing from a pregnant person to a baby during childbirth 

Risk Factors

Anyone sexually active can get chlamydia. The risk is higher in some situations, including⁴: 

• Sex without a condom with a person who has chlamydia 
• Having more than one sexual partner 
• Not using condoms correctly every time 
• Having a current or past STI 

Complications of Untreated Chlamydia in Men and Women

Many people with chlamydia have no symptoms. However, untreated infection can still cause complications in both men and women. 

• Pelvic Inflammatory Disease (PID): PID is an infection of the uterus, ovaries, or fallopian tubes and is considered the most important long-term complication of untreated chlamydia. It can happen when bacteria move from the vagina to the upper reproductive organs, such as the uterus, fallopian tubes, or ovaries⁵. Chlamydia and gonorrhoea are common STI-related causes of PID^5,6. 
• Ectopic Pregnancy: An ectopic pregnancy happens when a fertilised egg grows outside the uterus, most often in a fallopian tube. Ectopic pregnancy can result as a complication of tubal damage. Untreated chlamydia can increase the risk of ectopic pregnancy by damaging the reproductive tract⁷. 
• Pregnancy and Neonatal Complications: Chlamydia during pregnancy may increase the risk of delivery before time (preterm delivery)⁸. If chlamydia passes to a baby during childbirth, it can cause eye (conjunctivitis) and lung infections (pneumonia) in the baby.  
• Infertility: In men, untreated chlamydia can sometimes cause pain and swelling near the testicles, which may affect fertility. In women, infertility as a complication is usually a consequence of PID rather than as a result of direct chlamydia infection⁹. 
• Reactive Arthritis: This is joint inflammation that can occur after some infections, including chlamydia. It may also involve eye irritation and pain when passing urine⁹. 
• Higher Risk of HIV Infections: Untreated chlamydia may increase the risk of getting or passing on HIV³.

Diagnosis of Chlamydia

Chlamydia is usually diagnosed with a laboratory test on a urine sample or a swab from the area that may be infected, such as the vagina, cervix, penis, rectum, or throat. The best test depends on your symptoms, sexual history, and the area that may have been exposed¹⁰. 

• Nucleic acid amplification testing (NAAT): NAAT is the preferred test for chlamydia because it is highly accurate. It can be done on a urine sample or a swab. In women, a vaginal swab is preferred, and in men, first-catch urine is preferred^8,10.
• Blood antibody tests: These tests look for the body’s immune response to infection. They are not usually the first choice for diagnosing current genital chlamydia because they may not show when or where the infection happened^10,11. 
• Culture tests: Chlamydia can be difficult to grow in a laboratory, so culture tests are not used routinely. They may be considered in selected situations when the doctor needs more detailed information⁸.
• Rapid diagnostic tests (RDTs): Some rapid tests can give results quickly, within a few minutes, but may be less accurate than NAAT. Your doctor can advise whether a rapid test is suitable¹⁰.

Your doctor or sexual health clinic can recommend the most appropriate test for you. 

Treatment for Chlamydia

Chlamydia is treated with antibiotics. Treatment helps cure the infection, reduce the chance of passing it to others, and prevents complications. The antibiotic chosen depends on factors such as the site of infection, pregnancy, allergies, other health conditions, and local medical guidance. Treatment for men and women is usually similar, except in situations such as pregnancy. The following options are included in the WHO guidance for chlamydial infections¹². 

1. Uncomplicated genital chlamydia

WHO STI treatment guidelines recommend one of the following options:

• Azithromycin 1 g orally in a single dose 
• Doxycycline 100 mg orally twice a day for 7 days 

Other options may include tetracycline, erythromycin, or ofloxacin. Doxycycline, tetracycline, and ofloxacin are not recommended during pregnancy. 

2. Anorectal chlamydial infection

For chlamydia affecting the rectum or anus, WHO guidance prefers doxycycline 100 mg by mouth twice a day for 7 days. 

3. Chlamydial infection in pregnancy

WHO guidance recommends azithromycin as the preferred antibiotic in pregnancy. Amoxicillin is considered an acceptable alternative to azithromycin. Recommended doses include: 

• Azithromycin 1 g orally in a single dose 
• Amoxicillin 500 mg orally thrice a day for 7 days 

4. Chlamydial eye infection in newborns

For newborn eye infection caused by chlamydia, WHO guidance recommends azithromycin 20 mg/kg/day by mouth, once daily for 3 days. 

Treatment should also include a proper testing and management for recent sexual partners, because partners may have chlamydia even if they do not have symptoms. 

• Treating the sexual partners of infected people can help in preventing transmission to others, and treating pregnant women can help in preventing transmission to the baby¹³. 
• Recent sexual partners should be tested and treated if needed. People being treated should avoid sex for 7 days after a single-dose treatment, or until they finish a 7-day treatment course. HIV testing may also be recommended⁸.
• Chlamydia and gonorrhoea can occur together. Your doctor will decide whether testing or treatment for other STIs is needed based on your situation⁸. 
• Follow-up Recommendation: A retest is recommended after 3 months of treatment⁸.

Chlamydia is curable with antibiotics, but reinfection is possible. That is why retesting after about 3 months is often recommended.  

For a personal treatment plan, speak with a doctor or sexual health clinic. 

Prevention of Chlamydia

Preventing chlamydia focuses on lowering the chance of exposure and getting tested when needed. 

• Use condoms correctly every time during vaginal or anal sex. Condoms reduce the risk, although they do not remove it completely³.
• Consider a mutually monogamous relationship with a partner who has tested negative for STIs. 
• Get routine STI screening if you are at risk or if your healthcare provider recommends it¹⁴. 

This can help detect infection early and prevent spread. Screening during pregnancy can help avoid passing the infection to the baby¹⁵. 

• Avoid sex with a partner who has untreated chlamydia until treatment is complete. 
• After single-dose treatment, wait at least 7 days before having sex. If you are taking medicine for 7 days, wait until you have finished all the medicine³.

Also Read: Is HPV Herpes? Our Doctor Explains the Difference

When to See a Doctor?

See a doctor or visit a sexual health clinic if you or your partner has symptoms of chlamydia, if a partner has been diagnosed with an STI, or if you have had sex without a condom and are worried about infection. Pregnant people should ask about chlamydia testing. Regular testing is recommended for people at higher risk, including sexually active women aged 25 or below, older women with new or multiple sexual partners, people with a partner who has STI symptoms, and men who have sex with men³.

Conclusion

Chlamydia is a common STI caused by the bacterium Chlamydia trachomatis. It often causes no symptoms, so testing is important if you may have been exposed. If left untreated, chlamydia can affect reproductive and urinary health and may cause complications. The infection is curable with antibiotics, but treatment cannot always reverse damage that has already happened. If you are concerned about chlamydia, speak with a healthcare provider for testing and advice. 

Frequently Asked Questions (FAQs)

References

1. Chlamydia. Accessed July 27, 2026. Available from: https://www.nj.gov/health/sti/information/chlamydia/ 

2. CDC. About Chlamydia. Chlamydia. February 23, 2026. Accessed July 27, 2026. Available from: https://www.cdc.gov/chlamydia/about/index.html 

3. Chlamydia Infections. Accessed July 27, 2026. Available from: https://medlineplus.gov/chlamydiainfections.html 

4. Chlamydia. Communicable Diseases Agency. Accessed July 27, 2026. Available from: https://www.cda.gov.sg/professionals/diseases/chlamydia/ 

5. Pelvic inflammatory disease (PID): MedlinePlus Medical Encyclopedia. Accessed July 27, 2026. Available from: https://medlineplus.gov/ency/article/000888.htm 

6. Paavonen J, Lehtinen M. Chlamydial pelvic inflammatory disease. Hum Reprod Update. 1996 Nov-Dec;2(6):519-29. doi: 10.1093/humupd/2.6.519. PMID: 9111185. Available from: https://pubmed.ncbi.nlm.nih.gov/9111185/

7. Xia Q, Wang T, Xian J, et al. Relation of Chlamydia trachomatis infections to ectopic pregnancy. Medicine (Baltimore). 2020;99(1):e18489. doi:10.1097/MD.0000000000018489 Available from: https://pubmed.ncbi.nlm.nih.gov/31895782/

8. Mohseni M, Sung S, Rausch-Phung EA, Takov V. Chlamydia. In: StatPearls. StatPearls Publishing; 2026. Accessed July 27, 2026. Available from: http://www.ncbi.nlm.nih.gov/books/NBK537286/ 

9. Centre for Health Protection, Department of Health – Men’s Health Line – Chlamydia. Accessed July 27, 2026. Available from: https://www.chp.gov.hk/en/static/80030.html 

10. Meyer T. Diagnostic Procedures to Detect Chlamydia trachomatis Infections. Microorganisms. 2016;4(3):25. doi:10.3390/microorganisms4030025 Available from: https://pubmed.ncbi.nlm.nih.gov/27681919/

11. Numazaki K. Serological Tests for Chlamydia trachomatis Infections. Clin Microbiol Rev. 1998;11(1):228-229. doi:10.1128/cmr.11.1.228 Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC116715/

12. RECOMMENDATIONS FOR TREATMENT OF CHLAMYDIAL INFECTIONS. In: WHO Guidelines for the Treatment of Chlamydia Trachomatis. World Health Organization; 2016. Accessed July 27, 2026. Available from: https://www.ncbi.nlm.nih.gov/books/NBK379708/ 

13. Chlamydial Infections – STI Treatment Guidelines. August 15, 2022. Accessed July 27, 2026. Available from: https://www.cdc.gov/std/treatment-guidelines/chlamydia.htm 

14. Chlamydia. Communicable Diseases Agency. Accessed July 28, 2026. Available from: https://www.cda.gov.sg/public/diseases/chlamydia/ 

15. Chlamydia. Accessed July 27, 2026. Available from: https://www.who.int/news-room/fact-sheets/detail/chlamydia 

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