Trichomonas vaginitis is the most prevalent nonviral sexually transmitted disease in women.  The disease is caused by a flagellated protozoan, Trichomonas vaginalis, and primarily affects women during the reproductive years. The incubation period is usually 4-28 days. Trichomonas vaginalis has been isolated in 30-40% of male partners of infected women. Trichomonas vaginitis is often recurrent.

The main symptom of trichomoniasis is usually profuse vaginal discharge.  The discharge may be gray,  yellow,  or green,  and it has been described as having a “frothy” appearance. The discharge has a foul odor and may also cause dysuria. Punctate reddened areas may be present on the vaginal and cervical mucosa. The classically described sign of “strawberry cervix and upper vagina” is seen in only about 2% of cases. Observation of flagellated mobile organisms on a wet mount provides a more conclusive diagnosis.  The sensitivity of this test is approximately 50%.

Patients who are asymptomatic but have Trichomonas vaginalis identified during a routine Papanicolaou examination should be treated because 30% of such patients will become symptomatic within 3 months if no treatment is given.

The Pap test, however, may have a high false-positive rate-up to 20%. There is an office-based monoclonal antibody test for trichomonal antigens that has a sensitivity of 85-90%, but this test is rarely used because of its cost.

Treatment options for trichomonas vaginitis are shown in Table 15-1.

The woman’s sex partner is usually treated because the risk of reinfection is 2.5-fold greater when the partner is not treated.

Other, rarer types of vaginitis are occasionally seen in patients with cancer, including desquamative inflammatory vaginitis, erosive lichen planus of the vagina,  and vaginitis caused by group A streptococci.  Table 15-2 describes the diagnostic methods and treatment for these rare conditions.

Elizabeth R. Keeler, Pedro T. Ramirez, and Ralph S. Freedman
Committee on Gynecological Practice, the American College of Obstetricians and Gynecologists. Obstet Gynecol 2007

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