Chlamydia is itself silent: about three-quarters of infected women and half of infected men have no symptoms, so it spreads invisibly until someone gets tested or a complication appears. Talking about it openly is the only way to break that silence. It's the most-reported bacterial STI in the US — roughly 1.65 million cases in 2023 — and antibiotics cure it CDC AtlasPlus, 2023.
| Item | Reported cases |
|---|---|
| Chlamydia | 1,648,568 |
| Gonorrhea | 601,319 |
| Syphilis (P&S) | 53,007 |
What chlamydia actually is
Chlamydia is caused by the bacterium Chlamydia trachomatis; most US genital infections come from serovars D–K CDC, About Chlamydia. It's the most commonly reported bacterial STI in the country, with about 1.65 million reported cases in 2023 (492 per 100,000), a rate that has stayed roughly flat across 2020–2023. The burden isn't spread evenly. Washington DC (1,228 per 100,000), Louisiana (792), and Mississippi (701) all run more than double the national rate.
Silence is what spreads it. People assume "no symptoms" means "no infection," and that assumption keeps the cycle going. Testing positive is routine and curable — clinics handle it daily — and it says nothing about your character.
Symptoms — and the silent reality
Most infections cause nothing at all. About three-quarters of infected women and half of infected men carry chlamydia without noticing. When symptoms do show, they usually appear within 1–3 weeks of exposure.
In women
Women may notice abnormal vaginal discharge or burning on urination. If the infection climbs into the upper reproductive tract, it can bring lower abdominal or low-back pain, fever, pain during intercourse, and bleeding between periods. For a fuller breakdown, see chlamydia symptoms in women.
In men
Men may have penile discharge — often clear or cloudy, sometimes just a single morning drop — along with burning on urination, or burning and itching at the penile opening. Some develop testicular pain or swelling.
Rectal and throat infections
Rectal infection can cause pain, discharge, or bleeding, but it's often silent. Throat infections are typically asymptomatic, so testing the right sites matters more than waiting for a sign.
How chlamydia spreads
It passes through vaginal, anal, or oral sex. A pregnant woman can also pass it to her baby during childbirth. Because so many infections produce no symptoms, transmission usually happens between people who have no idea they're infected.
How chlamydia is tested
The nucleic acid amplification test (NAAT) is the recommended method for both genital and extragenital infection CDC STI Treatment Guidelines, 2021. Specimens can be a first-catch urine sample, or an endocervical, vaginal, male urethral, rectal, or pharyngeal swab — matched to where exposure happened.
In practice, testing is low-drama: you pee into a cup (hold your urine about an hour first) or collect your own swab — no blood draw and no urethral probe — and results are often texted back in 1–3 days. People often test the morning after a hookup, but a NAAT is most reliable about two weeks out, so an early negative can falsely reassure you. If you're unsure of timing, read when to test after exposure.
Testing is usually free or low-cost at Planned Parenthood, health departments, and Title X clinics; at-home kits run about $50–150 and it's often $0 with insurance. You can get tested or compare testing providers to find the right option, and the chlamydia testing & diagnosis guide covers the science in depth.
Who should be screened
The USPSTF (Sept 14, 2021, Grade B) recommends screening all sexually active women 24 or younger, and women 25 and older at increased risk, including pregnant persons USPSTF, 2021. For men, the evidence is judged insufficient (an I-statement). The screening guidance is asymmetric because the complication burden of PID and infertility falls on women. The CDC additionally recommends at least annual screening of sexually active men who have sex with men at all sites of exposure, every 3–6 months for those at higher risk, and HIV testing for everyone diagnosed with chlamydia.
Treatment
Antibiotics cure chlamydia. The preferred regimen is doxycycline 100 mg orally twice daily for 7 days CDC Chlamydial Infections. Alternatives are azithromycin 1 g as a single dose, or levofloxacin 500 mg once daily for 7 days. In pregnancy, azithromycin 1 g single dose is used (alternative: amoxicillin 500 mg three times daily for 7 days).
Azithromycin was downgraded from co-equal because microbiologic treatment failure in men was higher than with doxycycline, and doxycycline clears rectal infection far better — 100% versus 74% cure in one randomized trial RCT, Clin Infect Dis. Take doxycycline with food, avoid strong sun, and put the 3-month retest in your calendar. Full details live in the chlamydia treatment guide.
Partners and retesting
Refer, test, or presumptively treat partners from the prior 60 days, and abstain for 7 days after single-dose therapy or until the 7-day course is done. Otherwise reinfection bounces back and forth between you. Expedited partner therapy (giving you medication to deliver to a partner) measurably cut persistent or repeat infection in a landmark trial Golden et al., NEJM; it's permissible in most US states but not all, so verify local status.
Everyone should be retested about 3 months after treatment to catch reinfection. This is not a test-of-cure. A test-of-cure isn't advised for non-pregnant people unless adherence is in doubt, symptoms persist, or reinfection is suspected; pregnant patients get a test-of-cure about 4 weeks after completion and a retest at 3 months.
Complications if left untreated
Untreated, chlamydia is where the silence does its damage.
- In women: pelvic inflammatory disease (PID — infection of the upper reproductive organs), fallopian-tube scarring, ectopic pregnancy (a pregnancy implanted outside the uterus, which can be life-threatening), infertility, and chronic pelvic pain.
- In men: epididymitis (inflammation of the tube behind the testicle, causing pain and fever, and rarely sterility).
- Reactive arthritis (joint inflammation, formerly called Reiter syndrome) can follow infection in either sex.
- In newborns: chlamydia is a leading cause of early infant pneumonia and conjunctivitis (eye infection) after birth.
- It may also increase the risk of acquiring or transmitting HIV.
Lymphogranuloma venereum (LGV)
LGV is caused by invasive C. trachomatis serovars L1, L2, and L3, with the highest burden in men who have sex with men CDC, LGV. It usually shows up as proctocolitis — mucoid or hemorrhagic rectal discharge, anal pain, and tenesmus (a constant urge to pass stool). Treatment is doxycycline 100 mg twice daily for 21 days (alternatives: azithromycin 1 g weekly for 3 weeks, or erythromycin base 500 mg four times daily for 21 days), and partners within 60 days get presumptive doxycycline 100 mg twice daily for 7 days.
Prevention
Condoms used correctly every time lower risk, and so does a long-term mutually monogamous relationship with a tested partner. But since most infections are silent, the tools that actually move the needle are routine screening and treating partners promptly.
DoxyPEP is another option for eligible people: a single 200 mg dose of doxycycline within 72 hours of sex reduces chlamydia by more than 70% CDC DoxyPEP, 2024. The CDC offers it to men who have sex with men and transgender women who've had a bacterial STI in the past 12 months.
When to see a clinician
See a clinician if you have discharge, burning on urination, pelvic or testicular pain, or rectal symptoms — or if a partner tests positive, even with no symptoms of your own. If you're a sexually active woman 24 or under, or otherwise at increased risk, fold a chlamydia test into your routine care rather than waiting for a reason.