Oral Candidiasis (Thrust or Yeast Infection)

CHAPTER 53

Oral Candidiasis

(Thrush or Yeast Infection)

Presentation

An infant (who often has a concurrent diaper rash) has white patches in his mouth, or an older patient (who usually has poor oral hygiene, diabetes, a hematologic malignancy, an immunodeficiency, or who is on antibiotic, cytotoxic, or steroid therapy) may have few complaints or complains of a sore mouth and sensitivity to foods that are spicy or acidic. On physical examination, painless white patches are found in the mouth and on the tongue. The patches wipe off easily with a swab, leaving an erythematous base that may bleed. There also may be intense, dark red inflammation throughout the oral cavity.

What To Do:

If there is any doubt about the cause, confirm the diagnosis by smearing, Gram staining, and examining the exudate under a microscope for large, gram-positive pseudohyphae and spores. Mycologic confirmation can be achieved rapidly by 10% potassium hydroxide (KOH preparation) or normal saline microscopic examination. A fungal culture may also confirm the diagnosis but is usually unnecessary and does not distinguish between colonization and true infection.

Mild cases in infants may be watched without treatment. For topical treatment, prescribe an oral suspension of nystatin (Mycostatin), 100,000 U/mL; place 1 mL in each cheek for infants and 4 to 6 mL in each cheek for children and adults. Instruct the patient to gargle and swish the liquid in his mouth as long as possible before swallowing, 4 times a day, for at least 2 days beyond resolution of symptoms. Nystatin is also available in pastilles (lozenges) of 200,000 U; one or two pastilles can be dissolved in the mouth 4 to 5 times daily. Alternatively, for children younger than 3 years old, prescribe clotrimazole (Mycelex) in 10-mg troches to be dissolved slowly in the mouth 5 times a day for 7 to 14 days. The best time to administer medication is between meals, because this allows longer contact time. Nystatin suspension is the least expensive option, more palatable, and possibly more effective. When treating patients with diabetes, remember that nystatin suspension has a high sugar content.

For adults who do not have acquired immunodeficiency syndrome (AIDS), fluconazole (Diflucan), 100 mg qd for 14 days, may be a better regimen. Sometimes a single 200-mg oral dose is effective, but the longer course decreases the risk for recurrence. An acceptable compromise is to give 200 mg qd on day 1, followed by 100 mg qd for four more days. Itraconazole (Sporanox) suspension (10 mg/mL), 100 to 200 mg daily for 7 days, is as effective as fluconazole.

In patients with AIDS, give fluconazole, 200 mg on day 1, then 100 mg qd for 14 days or until improvement.

Have patients with removable dental appliances or dentures soak them overnight in a nystatin suspension to prevent reinfection with these contaminated objects.

Look elsewhere for Candida infection (e.g., esophagitis, intertrigo, vaginitis, diaper rash), and treat these conditions appropriately.

For healthy newborns or infants, reassure the parents about the benign origin and course of this minor superficial yeast infection.

What Not To Do:

Do not overlook diarrhea, rashes (other than diaper rash), failure to thrive, hepatosplenomegaly, or repeated infections that may suggest an underlying immunodeficiency. Beyond infancy, be especially vigilant for those patients who have no apparent underlying cause for thrush (e.g., antibiotics, steroids).

Discussion

Oropharyngeal candidiasis or thrush is a local infection commonly found in young infants, older individuals with poor oral hygiene or dentures, diabetics, or patients treated with antibiotics, steroids, chemotherapy, or radiation therapy. Thrush can also be found in those with a hematologic malignancy or immunodeficiency, such as human immunodeficiency virus (HIV)/AIDS.

In the healthy newborn, thrush is a self-limited infection, but it usually should be treated to avoid feeding problems. The neonate acquires the yeast from the mother at the time of delivery. Most often, thrush will appear at about 1 week of age; the incidence peaks around the fourth week of life. Infants who fail to respond to treatment with nystatin oral suspension can be given nystatin or clotrimazole vaginal suppositories placed in a split pacifier, which will provide a more prolonged topical application.

In adults, oral candidiasis is found in a variety of acute and chronic forms. The pseudomembranous form is the most common and appears as white plaques on the buccal mucosa, palate, tongue, or the oropharynx. The atrophic form does not have plaques, is more common in adults with dentures, and is known as denture stomatitis. This form of oral candidiasis presents with localized erythema and erosions with minimal white exudate, which may be caused by candidal colonies beneath dentures. It is severalfold more frequent in women than in men. Thrush may also present simply as a beefy red tongue.

Thrush may be the first sign of HIV infection; its appearance in advanced HIV indicates poor prognosis. Maintenance prophylaxis may be required in patients with AIDS who have several recurrences of symptomatic oral candidiasis. After an initial 200-mg dose, fluconazole can be continued at 100 mg qd or given intermittently (200 mg weekly). A recurrence rate of 10% to 20% can be anticipated with intermittent prophylaxis.

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