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Trichomonas vaginalis

Trichomonas, a flagellated anaerobic protozoan, is a sexually transmitted disease with a high transmission rate. Non-sexual transmission is possible because the organism can survive for a few hours.

Symptomatic women most often have a copious, yellow-gray or green homogeneous discharge. They may also describe a foul odor, vulvovaginal irritation, and, occasionally, dysuria. The pH level is usually greater than 4.5. Frothy discharge is present in less than 35% of infected patients, and punctate lesions, or "strawberry cervix," are seen in 25% trichomonas, vaginitis.

The diagnosis of trichomonal infection is made by examining a fresh wet-mount preparation for mobile, flagellated organisms. An abundance of leukocytes usually is seen.

Occasionally the diagnosis is reported on a Pap test.

Treatment of Trichomonas vaginitis

Metronidazole ( Flagyl), 2 g PO in a single dose for both the patient and sexual partner, or 500 mg PO bid for 7 days. Ten percent of patients experience nausea and vomiting with the 2-g dose.

Topical therapy with commercially available, topical metronidazole is not recommended because the organism may persist in the urethra and Skene's glands after local therapy.

Screening for coexisting sexually transmitted diseases should be completed.

Recurrent or recalcitrant infections

If patients are compliant but develop recurrent infections, treatment of their sexual partners should be confirmed. Cultures should be performed. In patients with documented persistent infection despite compliance with treatment by the patient and her partner(s), a resistant trichomonad strain may require high dosages of metronidazole (more than 2.5 g/d), often combined with intravaginal metronidazole suppositories prepared by a pharmacist (500 mg once or twice daily) for at least 10 days. Commercial preparations of metronidazole gel are not effective.

Pregnancy. Metronidazole is contraindicated during the first trimester. Patients may be treated after the first trimester with metronidazole. Clotrimazole, 100 mg vaginally qhs x 7-14 d, is 48% effective.

Other diagnoses causing vaginal symptoms

One-third of patients with vaginal symptoms will not have laboratory evidence of bacterial vaginosis, Candida, or Trichomonas.

Other causes of the vaginal symptoms include cervicitis, allergic reactions, and vulvodynia.

Atrophic vaginitis should be considered in postmenopausal patients if the mucosa appears pale and thin and wet-mount findings are negative.

Allergy and chemical irritation

Patients with a short history of vulvar irritation should be questioned about use of substances that cause allergic or chemical irritation, such as deodorant soaps, laundry detergent, vaginal contraceptives, bath oils, perfumed or dyed toilet paper, hot tub or swimming pool chemicals, and synthetic clothing.

Topical steroids and systemic antihistamines can help alleviate the symptoms until the irritant can be identified.