Candida albicans is the most frequent cause of fungal human disease in general and very much the most common cause of oral fungal involvement. The organism is a normal inhabitant of the oral cavity in 30 to 40% of the population. When the bacterial flora of the oral cavity is disturbed by antibiotic therapy, or in individuals who have diabetes mellitus, xerostomia (dry-mouth), weakened immunity (for example, AIDS), or severe debilitation, this otherwise harmless microorganism multiplies to cause overt lesions.

The causes and the course the disease:

Oral Candidiasis takes the form of a superficial, curdy, gray to white membrane that can be readily scraped off to reveal an underlying erythematous inflammatory base. In the milder expressions, there is minimal ulceration of the mucosal surface and only a superficial subepithelial inflammatory infiltrate. More severe oral infections may produce mucosal ulceration and a correspondingly greater inflammatory reaction.

In the debilitated, compromised host, the oral candidal infection may be spread into the esophagus by the introduction of a nasogastric tube. Even more threatening, in the vulnerable individual, is more widespread mucous-membrane infection with invasion of the fungi into the deeper tissues of the oral cavity, increasing the potential for bloodstream diffusion. Uncommonly, and in the vulnerable individual, oral candidiasis is followed by widespread mucous membrane infection that has greater potential for invasion and distribution.

The clinical features:

The patient with candidiasis may complain of a burning sensation, tenderness, or sometimes pain around the affected mucosa. Spicy foods will cause occasional discomfort because of the increased sensitivity of the affected mucosa. These infections were more common in women and in patients over 40 years old. Fifty percent of the patients came to them with a chief complaint of oral burning. The patient may report having been on a prolonged course of broad-spectrum antibiotics for a sore throat or other infection.

About oral candidiasis, four major types are recognized: (1) pseudomembranous; (2) hyperplastic; (3) erythematous (atrophic); and (4) angular cheilitis.

The pseudomembranous oral infection may show as fine whitish deposits on an ervthematous patch of mucosa or as more highly developed small, soft, white, slightly raised plaques that closely resemble to milk curds. The disease may range in severity from a single region to a diffuse whitish involvement of several or all the mucosal surfaces. The mucosa next to, or between, these whitish plaques appears red and moderately swollen. The plaques or pseudomembranes may be stripped off the mucosa, leaving a raw bleeding surface. When separate restricted sites are involved, the cheek mucosa and vestibule are the most frequent regions affected (followed by the dorsum of the tongue, palate, gum, floor of the mouth, and lips).

The hyperplastic type is characterized by white plaques which cannot be removed by scraping. The most common location is the cheek mucosa. In patients infected with HIV, the hyperplastic candidiasis most often is found in the lip commissures.

The erythematous (atrophic) type is characterized by a red appearance. The color intensity may vary from fiery red to a hardly distinct pink spot. Common locations are the palate and dorsum of the tongue, as in the so-called multifocal candidiasis in patients who are not infected with HIV but who are heavy smokers. However, erythematous candidiasis may also appear as spotty areas of the cheek mucosa. This is a characteristic feature of the HIV infection, but is often overlooked.

Angular cheilitis is characterized by cracks radiating from the angles of the mouth, often associated with small white plaques. In the elderly, this is not an unusual lesion and may be because of anemia, loss of chewing vertical dimension, or vitamin deficiency. But it should be remembered that when it is noted in a young man, it could be the first sign of an HIV infection. Today it is recognized the most important etiologic cause is Candida albicans. However, Staphylococcus aureus may also be present in some patients.

The differential diagnosis:

The diagnosis of candidiasis relies on the clinical features and the presence of Candida hyphae on smears examined by potassium hydroxide, periodic acid-Schiff or Gram stain.

As a rule all the keratotic lesions may be readily ruled out from consideration, since they cannot be easily removed by scraping. Necrotic white lesions that must be considered in the differential diagnosis are chemical burns, gangrenous stomatitis, superficial bacterial infections, traumatic ulcers, necrotic ulcers of systemic disease, and the mucous patch.

The mucous patch of syphilis is usually a discrete, small, white necrotic lesion on the tongue, palate, or lips, whereas candidiasis is usually much more diffuse. The accompanying skin lesions of secondary syphilis and the positive serologic findings readily distinguish the mucous patch from candidiasis.

Necrotic ulcers and gangrenous stomatitis of debilitating systemic disease may be difficult to differentiate from candidiasis because the latter entity is usually also found in patients with undermining secondary disease. As a general rule, if the ulcer is deep then candidiasis would not be the primary cause. Traumatic ulcers with necrotic surfaces can often be related to a history of specific trauma. Chemical burns sometimes closely mimic candidiasis. The distinction is usually made by an accurate history, disclosing that a medicament has been applied to the mucosa.

Superficial bacterial infections may occur in patients with debilitating disease and indeed may mimic pseudomembranous candidiasis. Culture of these lesions yielded generous bacteria such as staphylococci, Neisseria, coliform bacteria, and lactobacilli.

The recommended treatment:

The management of patients with oral candidiasis is twofold: (1) to identify, correct, or eliminate predisposing or precipitating causes and (2) to provide antifungal therapy.

The underlying systemic conditions (such as diabetes, malnutrition, and anemia) and the discontinuation of broad-spectrum antibiotics are recommended for the first approaches. Local resistance can be improved by good oral hygiene and by leaving dentures out as much as possible.

The six drugs that are chiefly used for antifungal therapy are gentian violet, nvstatin, amphotericin B, miconazole, clotrimazole, and ketoconazole. Nystatin and amphotericin have been the standard drugs used for oral candidal infections for the last 35 years. Each of these drugs is absorbed poorly from the gastrointestinal tract but is excellent for topical use on mucous membrane and skin lesions. Most dentists and physicians stress the importance of continuing antifungal therapy at least 2 weeks following disappearance of signs and symptoms of oral lesions.