Learn about
Chlamydia
Chlamydia is the most common bacterial STD in the United States — and the most commonly missed. The CDC estimates more than 1.6 million cases are reported each year, but the true number is higher because most people who carry it never develop symptoms. It spreads silently, causes lasting damage if untreated, and is curable with a single antibiotic course if caught in time. The challenge is that "in time" rarely happens without deliberate testing, because most people with chlamydia have no reason to suspect it.
Chlamydia Symptoms
Up to 75% of women and approximately 50% of men with chlamydia have no symptoms at all — across the full spectrum of infections, not just mild cases. When symptoms do occur, they appear 7–21 days after exposure. In women: unusual vaginal discharge, burning on urination, pelvic pain, or bleeding between periods. In men: clear or white penile discharge, burning on urination, or testicular pain. Rectal chlamydia may cause pain, discharge, or bleeding, or nothing at all. Pharyngeal (throat) chlamydia is almost always asymptomatic. Common misdiagnoses include UTI, yeast infection, or non-specific pelvic pain — a urine test or swab is the only reliable way to distinguish them.
Chlamydia Transmission
Chlamydia spreads through vaginal, anal, or oral sex with an infected person — condoms substantially reduce but do not eliminate risk. It can be passed from an infected mother to her baby during birth, potentially causing neonatal conjunctivitis or pneumonia. Importantly, chlamydia can infect the throat and rectum as well as the genitals, meaning site-specific testing (throat and rectal swabs) is needed for people who engage in oral or anal sex — a urine test alone will miss these infections.
Chlamydia Treatment
Chlamydia is curable with antibiotics. The current CDC-recommended treatment is doxycycline 100mg twice daily for 7 days — this has replaced single-dose azithromycin as the preferred regimen based on better efficacy data. Sexual partners from the previous 60 days should be tested and treated regardless of symptoms. Abstain from sex for 7 days after completing treatment and until all recent partners have been treated. Retesting 3 months after treatment is recommended — not to confirm the antibiotics worked, but because reinfection from an untreated partner is common.
Chlamydia Health Risks
If untreated, chlamydia ascends from the cervix or urethra into the reproductive tract. In women, this causes pelvic inflammatory disease (PID) — infection of the uterus, fallopian tubes, and ovaries — which the CDC estimates affects 10–15% of women with untreated chlamydia. PID is a leading preventable cause of infertility and ectopic pregnancy in the US. In men, untreated chlamydia can cause epididymitis, which in severe or recurrent cases affects fertility. Reactive arthritis — joint inflammation in the knees, ankles, or feet appearing 1–4 weeks after infection — affects both sexes. During pregnancy, untreated chlamydia increases risk of preterm birth and neonatal infection.
Chlamydia Prevention
Consistent condom use substantially reduces chlamydia transmission risk but doesn't eliminate it. Routine annual screening for all sexually active women under 25 is the CDC recommendation — regardless of symptoms or perceived risk. Men who have sex with men should be screened at all exposure sites (urethra, rectum, throat) at least annually. For people with multiple partners or inconsistent condom use, more frequent screening (every 3–6 months) is appropriate. Regular testing is the most effective prevention strategy because it interrupts the cycle of asymptomatic transmission.
Chlamydia Diagnosis
The standard test is a nucleic acid amplification test (NAAT) — the most sensitive method available. For women: a vaginal swab (self-collected or clinician-collected) or urine sample. For men: a urine sample. Throat and rectal swabs are needed for people who engage in oral or anal sex — these sites require site-specific testing and will not be detected by urine alone. The window period is typically 1–2 weeks after exposure; testing too early can return a false negative. At-home test kits using self-collected samples sent to a certified lab are a reliable alternative to clinic visits.
Chlamydia Complications
Untreated chlamydia ascending to the uterus and fallopian tubes causes PID — a leading cause of preventable infertility in the US, with 10–15% of untreated women developing it. Repeated infections substantially increase this risk. In men, epididymitis from chlamydia can cause chronic pain and reduced fertility in severe cases. Reactive arthritis affects both sexes, presenting as knee, ankle, or foot inflammation 1–4 weeks after infection. During pregnancy, untreated chlamydia increases risk of preterm birth, premature rupture of membranes, and neonatal conjunctivitis or pneumonia. Chlamydia also increases susceptibility to HIV acquisition and transmission.
Chlamydia Post-Diagnosis Advice
Complete the full 7-day doxycycline course — don't stop early even if you feel better. Abstain from sex for 7 days after finishing treatment and until all partners have been treated; sex during this period risks reinfection. Notify sexual partners from the last 60 days so they can be tested and treated regardless of symptoms — asymptomatic partners are still infectious. Retest at 3 months after treatment, since reinfection is common. If symptoms persist after completing treatment, return to your provider — rarely, treatment failure or a different infection may be the cause.
Chlamydia Myths & Facts
Myth: Chlamydia always causes symptoms. Fact: Up to 75% of women and 50% of men have no symptoms — testing is the only way to know.
Myth: You can only get chlamydia once. Fact: Reinfection is common; past infection provides no immunity.
Myth: Chlamydia can only be transmitted through penetrative sex. Fact: Oral and anal sex can transmit it to the throat and rectum.
Myth: A negative test means your partner is clear. Fact: Your test result doesn't indicate your partner's status — they need independent testing.
Myth: Chlamydia will go away on its own. Fact: Bacterial infections don't reliably self-clear; untreated chlamydia causes progressive reproductive damage.
Chlamydia FAQ
How long does it take to cure chlamydia?
With the current CDC-recommended regimen — doxycycline 100mg twice daily — treatment takes 7 days. Abstain from sex during treatment and for 7 days after completing the course. Retesting at 3 months after treatment is recommended to catch reinfection, which is common.
Can chlamydia go away on its own?
Rarely, and not predictably. In a very small proportion of cases the immune system may clear the infection, but this cannot be reliably anticipated. Untreated chlamydia continues to cause reproductive tract damage and remains transmissible during that time. Antibiotic treatment is the only way to reliably clear the infection.
