Management of Patients Who Have Vaginal Infections

Vaginitis is usually characterized by a vaginal discharge and/or vulvar itching and irritation, and a vaginal odor might be present. The three diseases most frequently associated with vaginal discharge are BV (replacement of the normal vaginal flora by an overgrowth of anaerobic microorganisms, mycoplasmas, and Gardnerella vaginalis), trichomoniasis (T. vaginalis), and candidiasis (usually caused by Candida albicans). Cervicitis can sometimes cause a vaginal discharge. Although vulvovaginal candidiasis (VVC) usually is not transmitted sexually, it is included in this section because it is frequently diagnosed in women being evaluated for STDs.

Various diagnostic methods are available to identify the etiology of an abnormal vaginal discharge. Laboratory testing fails to identify the cause of vaginitis in a minority of women. The cause of vaginal symptoms usually can be determined by pH and microscopic examination of fresh samples of the discharge. The pH of the vaginal secretions can be determined by narrow-range pH paper; an elevated pH (i.e., >4.5) is common with BV or trichomoniasis but might not be highly specific. Discharge can be further examined by diluting one sample in one to two drops of 0.9% normal saline solution on one slide and a second sample in 10% potassium hydroxide (KOH) solution. An amine odor detected immediately after applying KOH suggests BV. Cover slips are placed on the slides, and they are examined under a microscope at low- and high-dry power. Motile T. vaginalis or clue cells (epithelial cells with borders obscured by small bacteria), which are characteristic of BV, usually are identified easily in the saline specimen. WBCs without evidence of trichomonads or yeast are usually suggestive of cervicitis (see Cervicitis). The yeast or pseudohyphae of Candida species are more easily identified in the KOH specimen. However, the absence of trichomonads or pseudohyphae does not rule out these infections because several studies have demonstrated the presence of these pathogens by culture or PCR after a negative microscopic examination. The presence of objective signs of vulvar inflammation in the absence of vaginal pathogens, along with a minimal amount of discharge, suggests the possibility of mechanical, chemical, allergic, or other noninfectious irritation of the vulva. Culture for T. vaginalis is more sensitive than microscopic examination. In settings where microscopy is not available, alternative point-of-care tests may be used to diagnose vaginitis.