Multiple scenarios underlie refractory oral candidiasis

Indianapolis - As immunosuppression is a major risk factor for oral candidiasis and because HIV-infected patients are now spending less time as inpatients thanks to advances in antiretroviral therapy, clinicians may be seeing more cases of oral yeast infections in their everyday practice. Those cases can present a therapeutic challenge because of their medical complexity.

Awareness of potential pitfalls is important for enabling a successful outcome in any patient being treated primarily for refractory disease, says Ginat W. Mirowski, D.M.D., M.D.

One of the most common reasons why patients fail antifungal therapy for oral candidiasis is that the yeasts are being harbored against eradication in the crevices of an orally worn appliance. While the need to query about denture wear may be obvious when the patient is older, clinicians may overlook the potential for oral appliance wear in younger, seemingly healthy individuals. Those patients, however, may be using a retainer for orthodontic correction, an appliance for treatment of temporomandibular joint disease or an athletic mouthguard.

"It is amazing how uncomfortable some individuals feel about being seen by family members without their dentures in place. However, I jokingly explain to them that if they don't sleep with their shoes on, they shouldn't go to bed wearing their dentures. Trying to eradicate oral candidiasis in a patient wearing an oral appliance around the clock is analogous to trying to treat athlete's foot without ever taking the shoes and socks off to allow the feet to dry," Dr. Mirowski says.

Treatment failures Other factors to consider in patients whose oral disease fails to respond to conventional therapy include comorbidities and misdiagnosis. For example, the possibility of uncontrolled or occult diabetes should be investigated since the glucose content of the saliva will be elevated and fuel yeast growth in the presence of hyperglycemia.

When patients fail to respond to initial empiric therapy, it is also important to consider whether another condition is present mimicking yeast infection. Depending on the clinical manifestations, the differential diagnosis might include viral infections, vesiculobullous diseases, idiopathic burning mouth, or oral graft-versus-host disease. The history provides a useful start for diagnosing the latter entity, but a biopsy may be indicated and culture obtained in the evaluation of patients with refractory candidiasis. Nevertheless, culture results need to be interpreted carefully, Dr. Mirowski says.

"If the culture quickly comes back as positive - within a week - the patient is likely to have a yeast infection and should be treated based on the culture. However, a positive culture result after a month is probably indicative of colonization since Candida is present as a harmless commensal organism in the mouth and/or GI tract in 30 percent to 60 percent of the population," she explains.

Systemic solutions Dealing primarily with refractory cases in her tertiary care setting, Dr. Mirowski relies mostly on systemic treatment for oral candidiasis rather than topical modalities. Her drug of choice is fluconazole (Diflucan, Pfizer) administered in an off-label regimen that starts with a loading dose of two 100 mg tablets followed by100 mg once daily for three to four days and then tapered to once or twice a week for an additional one to three weeks.

She also mentioned that clinicians should be aware that unrecognized oral candidiasis is a common underlying cause for recalcitrant vulvar disease.

"Vulvar Candida infection can usually be cleared easily with a single-dose treatment, but that is not adequate for treating comorbid oral infection. If vulvar candidiasis does not respond, consider the possibility of cross-contamination via yeast passage from the mouth to the genital region through the GI tract," Dr. Mirowski says.

Disclosure: Dr. Mirowski owns some Pfizer stock as part of her investment portfolio.