What is Chlamydia? Symptoms, Testing, Treatments, and Preventions.

Chlamydia is the most commonly reported bacterial STI worldwide, and rates continue to climb among young adults aged 15–29, even today. The same quiet worry is still found in people’s eyes when the test comes back positive. The good news? Chlamydia remains one of the most curable STIs—if we find it early. The challenging news? In 2024 the CDC reported 1.64 million cases in the United States alone, and global estimates from WHO suggest more than 120 million new infections occur every year.

This article gives you everything you need to know right now—no shame, no outdated information, just clear, evidence-based guidance so you can protect yourself and the people you care about.

1. Introduction: What Is Chlamydia and Why It Still Matters in 2025

Chlamydia is caused by the bacterium *Chlamydia trachomatis*. It primarily infects the urethra, cervix, rectum, and sometimes the throat or eyes. What makes it uniquely stubborn and in that 70–90% of women and over 50% of men experience no symptoms at all, allowing silent spread for months or even years.

Recent data from the CDC’s 2024 Surveillance Report (released October 2025) show chlamydia cases rose 4.8% from 2023 to 2024, driven by reduced routine screening during the post-COVID healthcare shift and higher rates of partner change among dating-app users. In the UK, Public Health England recorded over 230,000 diagnoses in 2024—its highest number ever. The bacterium hasn’t changed dramatically, but our testing and treatment strategies have, which is why up-to-date information matters more than ever.

2. How Chlamydia Spreads (All Transmission Routes Including Lesser-Known Ones)

Most people know about vaginal and anal sex, but chlamydia has several under-discussed pathways:

• Vaginal or anal intercourse (with or without ejaculation) 
• Oral sex (fellatio, cunnilingus, anilingus) → throat (pharyngeal) infection 
• Sharing of sex toys without cleaning or condom coverage 
• Genital-to-hand-to-eye contact → conjunctivitis (rare but painful) 
• Vertical transmission from mother to newborn during vaginal delivery 
• Rectal infection from anal sex or from vaginal fluids spreading to the anus (common in women who have vaginal chlamydia)

Important 2025 note: Re-infection from untreated partners remains the leading cause of persistent or recurrent cases. A 2024 Lancet Infectious Diseases study found that 1 in 5 people treated for chlamydia were re-infected within 6 months—almost always from the same partner.

3. Symptoms in Women, Men, and Non-Binary/LGBT+ People

Up to 90% of infections are asymptomatic, but when symptoms do appear, they usually start 1–3 weeks after exposure.

Symptom	Women	Men	Rectal/Pharyngeal (any gender)
Abnormal discharge	Yes (yellowish, strong odor)	Yes (clear or white from penis)	Rectal mucus/pus
Painful urination	Common	Very common	Sometimes
Bleeding between periods	Common	N/A	Rectal bleeding
Lower abdominal pain	Common (PID risk)	Rare	Rectal pain or tenesmus
Pain during sex	Common	Rare	Pain with bowel movements
Testicular pain/swelling	N/A	1–2 % of cases	N/A
Sore throat	If oral exposure	If oral exposure	Persistent sore throat

Non-binary and transgender individuals on hormone therapy: Estrogen increases cervical/vaginal susceptibility; testosterone does not appear to change urethral risk significantly (2024 JAIDS cohort).

Patient story – Alex, 28 (they/them): 

“I had zero symptoms, just a routine check before starting testosterone. The nurse almost skipped the swab because I ‘looked fine.’ Positive rectal chlamydia from rimming. I’m glad I asked for the full panel test.”

4. Long-Term Complications If Untreated

Untreated chlamydia is not “no big deal.” Recent studies quantify the risk:

• Pelvic inflammatory disease (PID) in women: 10–16% within 12 months (2023 New England Journal of Medicine long-term follow-up) 
• Chronic pelvic pain: 18 % of women with PID 
• Infertility (tubal factor): 1 in 7 women with documented PID 
• Ectopic pregnancy risk: 8-fold increase 
• Epididymitis in men: up to 40 % develop chronic testicular pain (2024 Sexually Transmitted Infections journal) 
• Reactive arthritis (formerly Reiter’s syndrome): 1–3 % of untreated cases, especially in HLA-B27 positive individuals

5. How Chlamydia Is Diagnosed in 2025–2026

The gold standard remains nucleic acid amplification testing (NAAT) on urine or self-collected vaginal/rectal/throat swabs—99 %+ sensitivity.

Clinic testing is still excellent, but many patients now prefer the privacy and speed of at-home or direct-to-lab services. Services like STDcheck.com offer FDA-cleared 10-panel test (chlamydia, gonorrhea, HIV, syphilis, hepatitis, trichomoniasis, etc.) with results in 1–2 days. You order online, visit one of their 4,500+ nationwide Quest Diagnostics labs without an appointment, and results arrive in a secure portal. No awkward conversations, no paper trail on insurance.

Patient story – Sarah, 34: 

“I found out my ex was cheating. I couldn’t face my family doctor. STDcheck.com let me test the same day in a lab five minutes from work. Positive for chlamydia, treated the next week, and my new partner tested negative. Huge relief.”

6. Latest Treatment Guidelines (2025 CDC, WHO, BASHH)

The biggest change since 2021: doxycycline is now first-line therapy for uncomplicated urogenital, rectal, and pharyngeal chlamydia in adults.

Guideline Year	First-Line Treatment	Second-Line / Special Cases
CDC 2021	Azithromycin 1 g single dose OR Doxycycline 100 mg twice daily × 7 days (doxy preferred if rectal)	Levofloxacin, sitafloxacin (rare)
CDC/WHO/BASHH 2025	Doxycycline 100 mg twice daily × 7 days (all sites)	Azithromycin 1 g single dose ONLY if adherence concern or pregnancy
Pregnancy	Azithromycin 1 g single dose (preferred) or amoxicillin	Doxycycline contraindicated

Expedited Partner Therapy (EPT) – giving medication or prescriptions to partners without an exam – is legal in 47 U.S. states as of 2025 and remains critical to stopping ping-pong re-infection.

Disclaimer: This is not medical advice. For informational purposes only. Consult your GP or a qualified doctor for personal medical advice.

7. Antibiotic Resistance Update and Why Guidelines Changed

Although full-blown resistance to doxycycline or azithromycin is still rare (<3 % globally), microbiological “treatment failures” with azithromycin climbed to 15–20 % for rectal infections by 2023 (IUSTI-Europe 2024 data). A landmark 2023–2024 randomized trial in The Lancet showed doxycycline cured 100 % of rectal and 98.5 % of urogenital infections versus only 76 % and 92 % for azithromycin. That evidence flipped the guidelines worldwide in 2025.

Disclaimer: This is not medical advice. For informational purposes only. Consult your GP or a qualified doctor for personal medical advice.

8. Prevention Strategies That Actually Work in Real Life

1. Consistent condom/dental dam use (reduces risk by ~90 % when used perfectly) 
2. Regular screening every 3–6 months if you have new or multiple partners 
3. Mutual testing with new partners before unprotected sex 
4. Post-exposure doxycycline (doxy-PEP) – 200 mg within 72 hours of condomless sex – reduced chlamydia by 74 % in San Francisco/LA 2024–2025 trials (CDC now studying for broader rollout) 
5. Vaccination research – mRNA and protein subunit vaccines in phase 2 trials (expected 2029–2032)

9. Chlamydia and Pregnancy: Risks and Screening Recommendations

All pregnant individuals should be screened at the first prenatal visit, again in the third trimester, and at delivery if high risk (CDC 2025). Untreated chlamydia causes preterm birth (RR 1.5), low birth weight, and neonatal pneumonia or conjunctivitis in 30–50 % of exposed infants.

Patient story – Maya, 26: 

“I tested positive at 16 weeks. One dose of azithromycin, re-tested negative at 20 weeks, and my daughter was born healthy at 39 weeks. I wish I’d known routine screening was standard—I almost skipped it.”

10. FAQs – Frequently Asked Questions

11. When You Should Get Tested? – Today!

Get tested now if you:

• Had condomless sex with a new partner in the last 3 months 
• Received a partner notification 
• Have any unusual discharge, pain, or bleeding 
• Are pregnant or planning pregnancy 
• Simply want peace of mind before your next relationship

Waiting “to see if symptoms appear” is the single biggest reason complications happen. Confidential services like STDcheck.com let you order a comprehensive panel test today, walk into a nearby lab tomorrow, and have results before the weekend.

12. Conclusion and Key Takeaways

Chlamydia is common, curable, and almost entirely preventable with today’s tools. The 2025 message is simple: test early, treat completely, notify partners, and re-test in 3 months. You deserve sexual health without anxiety.

Chlamydia is often a “silent” infection, detectable through routine sexual health screening. Early detection and treatment can prevent transmission and reduce the risk of complications. Consult a healthcare professional or a sexual health clinic for advice and testing if you suspect exposure or infection.

Take control right now—visit stdcheck.com to order fast, private, FDA-approved testing and know your status in 1–2 days.

You’ve got this.

13. Trusted Resources for Chlamydia

• CDC Chlamydia Facts (2024-2025)
• Find STD Testing Near You
• Planned Parenthood Clinics & Info
• WHO Global Guidelines
• At-Home Testing Kits
• 24/7 Hotline: 1-800-232-4636 (confidential)