Vaginal Infection, Trichomonas vaginitis, Trich, Trichomonal Vaginitis

What is Trichomoniasis?

Trichomoniasis is an infection of the vagina and urethra caused by the one-celled Trichomonas vaginalis. This sexually transmitted disease is common worldwide and growing in incidence, especially in HIV-infected persons.

Males are subject to the infection but usually have no symptoms, which is a factor contributing to the spread and persistence of the disease. The infection is often seen in combination with gonorrhea or chlamydia infection. It is easily treatable.

How is it diagnosed?

Trichomoniasis signs and symptoms

  • Foul-smelling, frothy vaginal discharge that is most noticeable several days after a menstrual period.
  • Vaginal itching and pain.
  • Redness of the vaginal lips (labia) and vagina.
  • Painful urination, if urine touches inflamed tissue.

The severity of discomfort varies greatly from woman to woman and from time to time in the same woman. Infected men may have no symptoms.

History is of irritation of the vagina or vulva, often including a vaginal discharge around the time of menstruation or during pregnancy. Some women also have pain or burning with urination. Symptoms may be absent in males. There may be a history of contact with an infected person or promiscuous sexual activity.

Physical exam may show a green or yellow, foul-smelling vaginal discharge. The vulva or vagina may be inflamed. Severe cases may also show inflammation of the cervix. There may be a discharge from the urethra. In males, inflammation of the prostate may be detected.

Tests: T. vaginalis is usually diagnosed by examining the vaginal or urethral discharge under a microscope and identifying the organism. Several specimens may be needed to detect T. vaginalis. The organism may also be found on urinalysis. Culturing of the organism, although difficult, may be performed using vaginal or urethral discharges. An immunologic blood test for T. vaginalis is a very effective confirmatory test. Culture for gonococcus and chlamydia should also be performed.

How is Trichomoniasis treated?

Trichomoniasis is treated with an antibiotic. All sexual partners should be treated simultaneously. If initial treatment fails, higher drug concentrations are used for a second round of treatment. Drug treatment should be avoided in the first trimester of pregnancy.


Information Brand Generic Label Rating
Flagyl 400 mg Flagyl Metronidazole On-Label


Avoid overexertion, heat and excessive sweating. Delay sexual relations until you are well. Allow about 10 days for recovery.

What might complicate it?

The development of drug resistant strains has been reported, and infection with these strains may lead to chronic trichomoniasis. Chronic trichomoniasis may cause cellular changes that can be misinterpreted on Pap smear.

Predicted outcome

The prognosis for treated trichomoniasis is excellent. But, if any sexual partner(s) is not treated, reinfection is likely.


Various bacterial and chlamydial infections of the urinary and genital systems may give similar symptoms. Pelvic inflammatory disease may also present with a similar history.

Appropriate specialists

Gynecologist, urologist, and infectious disease specialist.

Notify your physician if

  • You or a family member has symptoms of trichomonal vaginitis.
  • Symptoms persist longer than 1 week or worsen, despite treatment.
  • Unusual vaginal bleeding or swelling develops.
  • After treatment, symptoms recur.

Last updated 17 November 2015


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