Candidiasis is caused by the yeast Candida albicans and other Candida species, which are normal body flora found in the skin, mouth, vagina, and intestines. Although considered a yeast, C. albicans is dimorphic and can form a true mycelium. Infections occur when competing bacterial flora are eliminated, for example, by antibacterial antibiotics, allowing the yeast to overgrow. Candida infections have various manifestations, depending on the site and the degree of immunoincompetence of the patient. For example, oral candidiasis (thrush) presents as raised, white plaques on the oral mucosa, tongue, or gums. The plaques can become confluent and ulcerated and spread to the throat. Most HIV-positive individuals eventually develop oral candidiasis, which often spreads to the esophagus. The latter condition is considered an indicator of full-blown AIDS. Vaginal candidiasis presents as itching and burning pain of the vulva and vagina, accompanied by a white discharge. Systemic candidiasis is a potentially life-threatening infection that occurs in debilitated individuals, cancer patients (with neutropenia secondary to chemotherapy), individuals on systemic corticosteroids, and patients treated with broad-spectrum antibiotics, especially those with long intravenous catheters. Systemic candidiasis may involve the gastrointestinal (GI) tract, kidneys, liver, and spleen. Both oral and vaginal infections are treated topically with nystatin or clotrimazole. Depending on the severity and extent of a candidal infection, treatment with an azole drug, such as ketoconazole, fluconazole, and itraconazole, may be given orally or intravenously. Amphotericin B by itself or in combination with flucytosine is used in systemic disease. Echinocandins, such as caspofungin, micafungin and anidulafungin are active against Aspergillus and most Candida, including those species resistant to azoles.

     [ Oral candidiasis (thrush) ]