Chlamydia Infections: Symptoms, Diagnosis, Treatment, Prevention

Chlamydia is the most common sexually transmitted disease(STD) in the US that can infect both men and women. Chlamydia trachomatis, commonly known as Chlamydia, or C. trachomatis, is a bacterium that can afflict the cervix in women and the urethra and rectum in both men and women. Occasionally the eyelid lining and throat can be affected.

Chlamydia trachomatis affects all age groups, and prevalence is highest in persons aged ≤24 years. More than half of the affected people have no symptoms. Chlamydia isn’t difficult to treat. If left untreated, however, it can cause serious, permanent damage to a woman’s reproductive system, including PID, ectopic pregnancy, and infertility.


Asymptomatic infection is common among both men and women. In fact, about 75% of infections in women and 50% in men are without symptoms.

If you do have symptoms, they usually appear one or two weeks after exposure to Chlamydia. Even when Chlamydia causes no symptoms, it can damage a woman’s reproductive system.

Women with symptoms may notice

  • an abnormal vaginal discharge;
  • a burning sensation when urinating;
  • low abdominal pain;
  • painful sexual intercourse;
  • irregular vaginal bleeding.

Symptoms in men can include

  • a discharge from their penis;
  • a burning sensation when urinating;
  • pain and swelling in one or both testicles (although this is less common).

Men and women can also get infected with Chlamydia in their rectum. This happens either by having receptive anal sex, or by spread from another infected site (such as the vagina). While these infections often cause no symptoms, they can cause

  • rectal pain;
  • discharge;
  • bleeding.


Diagnosis of chlamydia is relatively simple. Tests include:

  • a first-catch urine specimen;
  • a swab specimen from the endocervix or vagina(women) or a urethral swab(men).

Since most people don’t have signs or symptoms when they’re infected by Chlamydia, the Centers for Disease Control and Prevention recommends annual screening for

  • all sexually active women aged <25 years;
  • older women at increased risk for infection (e.g., those who have a new sex partner, more than one sex partner, a sex partner with concurrent partners, or a sex partner who has a sexually transmitted infection).


Chlamydia infection is treated with antibiotics. Chlamydia treatment should be provided promptly for all persons testing positive. Treating their sex partners can prevent reinfection.

Recommended Regimens
  • Azithromycin 1 g orally in a single dose
  • Doxycycline 100 mg orally twice a day for 7 days
Alternative Regimens
  • Erythromycin base 500 mg orally four times a day for 7 days
  • Erythromycin ethylsuccinate 800 mg orally four times a day for 7 days
  • Levofloxacin 500 mg orally once daily for 7 days
  • Ofloxacin 300 mg orally twice a day for 7 days

Having chlamydia or having been treated for it in the past provides no immunity against reinfection in the future.


The most common ways to contract Chlamydia are the following:

  • unprotected intercourse (vaginal, anal) with an infected partner;
  • sharing sex toys;
  • from mother to the newborn during vaginal childbirth;
  • from fingers to other parts of the body, e.g. the eyes.

To protect yourself from contracting Chlamydia, you could

  • use condoms;
  • limit your sex partners;
  • get regular screening;
  • avoid douching.

* The Content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.