Vulvovaginal Yeast Infections
1. What every clinician should know
Vulvovaginal candidiasis (VVC) is a common cause of irritative lower genital tract symptoms in women. Approximately 75% of women will experience at least one episode of VVC during their life time, while up to 45% will experience two or more episodes. Chronic, recurrent VVC (RVVC) is defined in women experiencing four or more episodes within a year and occurs in less than 5% of women.
The normal vaginal flora is characterized by a predominance of hydrogen peroxide-producing lactobacilli. These microorganisms by virtue of secreting both lactic acid and H2O2 are important in maintaining a normal bacterial ecology in the vagina. Antibiotics, by virtue of decreasing the numbers of lactobacilli, predispose to an overgrowth of Candida albicans and other yeasts often causing symptoms of VVC. Pregnancy and diabetes are also risk factors for the development of VVC in that these diseases have a qualitative depressing effect on local immune mechanisms allowing for an overgrowth of yeast.
2. Diagnosis and differential diagnosis
Women with lower genital tract symptoms, such as a change in vaginal discharge, vulvar irritation, itching or burning, and/or external dysuria should be evaluated for VVC. An external exam of the vulva and vestibule should be performed looking for erythema, fissures, and satellite lesions that appear as a small pustulopapular rash. A speculum exam should then be performed to evaluate the character of the vaginal secretions. Women with VVC will commonly have a cheesy vaginal discharge and the vagina may be erythematous.
A specimen of the vaginal secretions should be obtained. This is best obtained with a cotton swab and placed in a test tube with 0.5 cc of normal saline. A single drop of this preparation can then be decanted onto a slide and covered with a slip for microscopic examination. Characteristically, fungal elements will be observed.
If the vaginal epithelial cells obstruct the examiner’s view, add 10% potassium hydroxide (KOH) in order to remove the obstructing vaginal epithelial cells. If fungal hyphae are confirmed, then a vaginal yeast culture is not necessary. On the other hand, if fungal elements are not seen, a vaginal culture for yeast is recommended to either confirm or rule out the diagnosis of VVC.
Vaginal yeast culture
Microscopically the fungal elements will either be hyphae or budding yeast forms. If budding yeast forms are visualized, culture is important to rule out non-albicans Candida which tend to be more resistant to standard treatment. Women with four or more episodes of VVC in a year should have a vaginal yeast culture to rule out the possibility of non-albicans Candida as well. A yeast culture can be submitted to your lab using the same culturette used for sampling the vagina for GBS except you need to label the culture “vaginal yeast culture.”
Women with lower genital tract symptoms but no signs of vulvovaginitis, and a negative microscopy for fungal elements will have yeast cultured from the vagina only 14% of the time. For this reason, women presenting with this constellation of symptoms and signs and a negative wet mount should not receive empiric therapy prior to obtaining the yeast culture results.
The differential diagnosis of lower genital tract symptoms include VVC, bacterial vaginosis (BV), trichomonas vaginitis (TV) and cervicitis. Women with BV or TV generally have an abnormal vaginal pH (>4.5). In addition, women with BV will have clue cells noted during microscopy of the vaginal secretions and a positive whiff test (a fishy, amine odor noted with the addition of 10% KOH).
TV is diagnosed when motile trichomonads are noted during microscopy but this is a relatively insensitive test (~65%) and culture should be considered in women with an elevated pH and an increased number of leukocytes noted during microscopy.
Cervicitis can be diagnosed when a green or yellow mucopurulent exudate is noted from the endocervix and friability (easy bleeding) is noted when the endocervix is sampled with a cotton swab.
The management of women with VVC requires an assessment as to whether their infection is uncomplicated or complicated VVC.
Uncomplicated VVC occurs in immunocompetent women with mild to moderate symptoms having infrequent episodes of confirmed VVC where hyphae are noted microscopically. Women with uncomplicated VVC may be treated with any one of the several available over-the-counter topical antifungals, including miconazole, tioconazole, terconazole, butaconazole, or clotrimazole. An alternative to topical therapy is the single 150 mg dose of oral fluconazole.
Complicated VVC is characterized in women with moderate to severe symptoms who may be immunocompromised (e.g. AIDS/HIV infection, steroid therapy, uncontrolled diabetes, etc) or who have frequent recurrences (>4 per year). Women with complicated VVC are candidates for more prolonged therapy. These patients should receive fluconazole 150mg orally every three days for three doses. This will induce remission of their symptoms. To prevent recurrence, they should be maintained on weekly fluconazole 150mg orally for six months. After six months of suppressive therapy, the fluconazole can be discontinued. If relapse occurs, then reinitiation of fluconazole maintenance is recommended. Patients who are unable to take weekly fluconazole may substitute with weekly intravaginal miconazole 1200mg.
Some patients with significant vulvar erythema benefit from a short course of a topical steroid, such as triamcinalone cream applied to the area twice daily. They can also use co-formulated triamcinolone or Betamethasone (topical steroid) plus antifungal like nystatin or clotrimazole.
RVVC can lead to significant dyspareunia from the associated inflammation and fissuring of the vestibule. Occasionally medical therapy for complicated VVC, although successful in controlling recurrent acute symptoms, may not be successful in normalizing an already damaged vulvar vestibule epithelium. Dyspareunia in these patients may persist despite control of the infection. Although rare, if these women fail to respond to topical steroid therapy, they may require medical management of dyspareunia or surgical management with vestibulectomy to overcome the severe dyspareunia.
Lichen simplex chronicus
Another uncommon complication of RVVC is the initiation of a chronic itch/scratch cycle resulting in lichen simplex chronicus. This disease leads to a thickened vulvar epithelium characterized by excoriations from intractable scratching. Treatment consists of antifungal therapy as noted above for complicated VVC as well as an agent to combat the pruritus such as oral hydroxyzine or doxepin to allow a restful sleep.
The thickened vulvar epithelium will require a minimum of six weeks of twice daily applications of a topical steroid such as triamcinolone or in the case of more severe cases, clobetasol. Lichen simplex chronicus is commonly recalcitrant to therapy and requires persistence from both patient and provider to reverse the skin changes seen with this disease. Therapy is commonly months long.
5. Prognosis and outcome
Women with uncomplicated VVC promptly respond to any of the available topical antifungal medications. Women using oral fluconazole should be advised that it may take approximately 48 hours for the resolution of symptoms. Some providers may wish to augment a prescription for oral fluconazole with the addition of a topical steroid cream (e.g. 1% hydrocortisone cream or 0.1% triamcinalone cream) to speed the resolution of vulvar burning and itching.
Women with RVVC can also be confident that their chronic, recurrent symptoms will resolve with more prolonged therapy with fluconazole. This is effective over 90% of the time. If the patient fails to respond to this regimen, the diagnosis should be questioned. Some of these women may have a vulvar dermatologic condition or vulvodynia.
Less commonly (<5% of the time) the patient’s infection may be due to a more resistant non-albicans Candida (e.g. Candida tropicalis or Candida glabrata). Treatment of these infections are best done in consultation with an expert. Alternative therapies for the more resistant Candida species include boric acid suppositories or flucytosine cream, both of which require formulation in a compounding pharmacy.
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