Vaginitis: Trichomonas

Introduction

• Description: Trichomonas vaginitis is a vaginal infection caused by an anaerobic flagellate protozoan, Trichomonas vaginalis.

• Prevalence: Approximately 3.7 million cases per year in the United States (2.1% of women); accounts for 25% of “vaginal infections.” The most common nonviral sexually transmitted infection (STI).

• Predominant Age: 15–50 years (may occur at any age). One study found a peak rate at ages 47–53 years.

• Genetics: No genetic pattern.

Etiology and Pathogenesis

• Causes: Trichomonas vaginalis, an anaerobic flagellate protozoan in humans as the only natural host. The incubation period for Trichomonas infections is considered to be between 4 and 28 days.

• Risk Factors: Multiple sexual partners, vaginal pH that is less acidic (blood, semen, or bacterial pathogens increase the risk).

Signs and Symptoms

• Asymptomatic (70%–85%)

• Vulvar itching or burning

• Copious discharge with a rancid odor (generally thin, runny, and yellow-green to gray in color; “frothy” in 25%)

• “Strawberry” punctation of the cervix and upper vagina (up to 15%, pathognomonic when present)

• Dysuria

• Dyspareunia

• Edema or erythema of the vulva

Diagnostic Approach