Chlamydia — The most common STD you might not know you have

Chlamydia has become the most common bacterial sexually transmitted disease (STD) in the United States, but most people with chlamydia notice no symptoms. If left untreated, it can cause pelvic inflammatory disease and fertility problems.

According to Washington University infectious disease specialist Bradley Stoner, MD, PhD, “Because the symptoms can be almost non-existent, the number of reported cases of chlamydia is substantially lower than the actual cases. Recent data suggests that there are more than 2.8 million cases of chlamydia in the United States annually.”

Anyone who is sexually active is at risk. Infections can be spread during any kind of sexual activity – vaginal, anal or oral intercourse. The chlamydia organism lives only in human cells and can only be transmitted by having sexual intercourse with an infected person. It cannot be spread by other means – such as casual contact through clothing, towels or toilet seats.

What are the symptoms?

Dr. Stoner explains, “Since most cases of chlamydia are asymptomatic, it is most often diagnosed through screening, which is why it is so important to have good screening programs in place.”

A minority of cases will experience symptoms, and these can differ for men and women.Women may develop:

  • Abdominal pain
  • Discharge from the cervix (with or without odor)
  • Pain during sex
  • Bleeding after sex
  • Bleeding between periods

Men may have these symptoms:

  • Burning on urination
  • Discharge from the penis
  • Painful testicles

Long-term effects

Women are more likely than men to have long-term health consequences as a result of untreated chlamydia. These may include:

  • Severe infection with pain and fever
  • Pelvic inflammatory disease (infection of the upper reproductive tract)
  • Scaring in the reproductive tract that causes infertility

Other complications of chlamydia may include arthritis and conjunctivitis (eye infection) in both men and women. The infection can also be passed from a woman to her newborn during childbirth, causing the newborn to develop eye infections and pneumonia.

Treatment and prevention

Antibiotics such as azithromycin (Zithromax ®) and doxycycline (Doryx ®) are highly effective for treating a chlamydia infection.

Having chlamydia once does not make a person immune to ever contracting it again. If you have sex with an infected person, you can get it again – even if you have just completed treatment with antibiotics.

Dr. Stoner says, “To reduce your risk of infection, always use latex condoms when having intercourse of any kind. Abstaining from sexual contact is another way to prevent the spread of chlamydia.”


Screening for chlamydia is painless. For women, a specimen is swabbed from your vagina. For men, it is a urine sample.

You should be screened annually for chlamydia if you are:

  • Under 25 and sexually active
  • Over 25 and have multiple sexual partners
  • Have a sexual partner who has multiple sexual partners

“If you think you have been exposed to chlamydia, “Dr. Stoner adds, “see your healthcare provider to receive antibiotic medication to prevent the onset of infection.”

For more information on chlamydia or other STDs or to make an appointment with an infectious disease specialist, please call 314-747-1206.