What Is It?

Candidiasis is an infection caused by species of Candida fungi, especially Candida albicans. These fungi are found almost everywhere in the environment, and some may live harmlessly along with the abundant "native" species of bacteria that normally colonize the mouth, gastrointestinal tract and vagina. Usually, Candida is kept under control by the native bacteria and by the body's immune defenses. If the number of native bacteria is decreased by antibiotics or if the patient's immune defenses are weakened by illness (especially AIDS or diabetes), malnutrition, or certain medications (corticosteroids or anticancer drugs), Candida fungi can multiply enough to cause symptoms. Candida infections also can create occasional symptoms in healthy people. Candidiasis can affect many different parts of the body, causing either localized infections or overwhelming illness, depending on the patient and his or her underlying health.

• Thrush - Thrush is the common name for a mouth infection caused by the Candida albicans fungus. It affects moist surfaces around the lips, inside the cheeks, and on the tongue and palate. Thrush is common in people with diseases such as cancer and AIDS, which suppress the immune system. It also can develop in people with normal immune systems, particularly people who have diabetes or who have long-lasting irritation from dentures.

• Esophagitis - Candida infections of the mouth can spread to the esophagus, causing esophagitis. This infection is most common in people with AIDS and people receiving chemotherapy for cancer.

• Cutaneous (skin) candidiasis - Candida can cause skin infections, including diaper rash, in areas of skin that receive little ventilation and are unusually moist. Some common sites include the diaper area; the hands of people who routinely wear rubber gloves; the rim of skin at the base of the fingernail, especially for hands that are exposed to moisture; areas around the groin and in the crease of the buttocks; and the skin folds under large breasts in women.

• Vaginal yeast infections - Vaginal yeast infections are not usually transmitted sexually. During a lifetime, 75% of all women are likely to have at least one vaginal Candida infection, and up to 45% have two or more. Women may be more susceptible to vaginal yeast infections if they are pregnant or have diabetes. The use of antibiotics, use of birth control pills, or frequent douching also can promote yeast infections.

• Deep candidiasis (for example, candida sepsis) - In deep candidiasis, Candida fungi contaminate the bloodstream and spread throughout the body, causing severe infection. This type of candidiasis is especially common in newborns with very low birth weights and in patients with severely depleted immune systems or severe medical problems. In these people, Candida fungi may get into the bloodstream through skin catheters, tracheostomy sites, ventilation tubing or surgical wounds. Deep candidiasis also may occur in healthy people if Candida fungi enter the blood through intravenous drug abuse, severe burns or wounds caused by trauma.