Chlamydia Overview

Nongonococcal urethritis (NGU) is a nongonorrheal bacterial infection of the urethra (tube that carries urine out of the body) in men. NGU involves Chlamydia trachomatis, which causes chlamydia. The term NGU refers to the condition in men and chlamydia refers to the condition in women.

Incidence and Prevalence of Chlamydia

According to the Centers for Disease Control and Prevention (CDC), chlamydia is the most common bacterial infection in the United States. About 1.4 million new cases were reported in 2012. However, because as many as 75 percent of infected women and 50 percent of infected men do not experience symptoms of infection, the CDC estimates that up to 2.8 million new cases may occur each year in the United States.

Chlamydia is most prevalent among teenagers. Nearly 75 percent of all new cases occur in women under the age of 25. By age 30, 50 percent of sexually active women have been exposed to chlamydia. NGU is the most commonly diagnosed sexually transmitted disease in men in the United States.

Causes of Chlamydia

Bacteria are spread through direct sexual contact involving the genitals, anus, or mouth. Several types of bacteria cause NGU and many are undetectable during diagnosis. The most common are Chlamydia trachomatis (causes 50 percent of cases), Mycoplasma genitalium, and Ureaplasma urealyticum.

Signs and Symptoms of Chlamydia

Most people who develop NGU for the first time do so 1 to 3 weeks after having sex with a new partner. Symptoms may be similar to those of gonorrhea and include yellow or clear urethral discharge; pain and tenderness in the genitals; pain, burning, and itching during urination; and low-grade fever. Oral-genital or oral-anal contact can result in throat infection (pharyngitis) and inflammation of the rectum (proctitis).

Some women experience pain or cramping in the lower abdomen, especially during intercourse, and bleeding between menstrual periods. Inflammation of the cervix (cervicitis) with discharge is common. Notably, most infected women and 50 percent of infected men experience no symptoms.

Chlamydia Complications

In men, untreated NGU can cause epididymitis, inflammation of the reproductive system that may result in fertility problems. NGU symptoms resolve in about 60% of untreated chalmydial infections.

About 40 percent of women with untreated chlamydia develop pelvic inflammatory disease (PID), which creates a risk for infertility, endometriosis, and other reproductive tract problems.

Pregnant women with chlamydia are at increased risk for miscarriage and premature detachment of the placenta (abruptio placentae). Babies born to infected women may suffer eye, ear, genital, and lung infections; serious infection can be fatal to an infant.

Women with chlamydia are 3 to 5 times more likely to become infected with HIV if they are exposed to the virus.

Chlamydia Diagnosis

Diagnosis involves observing signs and symptoms and analyzing urethral discharge (usually at least 4 hours after urination). Urine is usually collected in the morning. Urethral inflammation may be noticeable. If discharge is present, a sample is collected and cultured to determine the presence of and identify bacteria. Blood tests are performed to check for signs of infection. A small cotton swab is inserted just inside the urethra to collect cells to check for other STDs.

Because infection may be asymptomatic, people with multiple sex partners should be tested annually, even if they feel fine.

Treatment for Chlamydia

Antibiotics are used to fight the infection; treatments may vary for men and women. A single dose of azithromycin (Zithromax) or a 7-day course of doxycycline (Periostat) usually is prescribed. Erythromycin is the preferred treatment for pregnant women, nursing mothers, infants, children, and adults unable to tolerate tetracycline. Recurrent NGU that is not associated with re-exposure may be treated with a drug that was not previously used. Ofloxacin (Floxin) may be used for recurrent NGU if white blood cell count is high.

Publication Review By: Stanley J. Swierzewski, III, M.D.

Published: 09 Jun 1998

Last Modified: 04 Sep 2015