What is thrush infection?

Definition

Thrush is a fungal infection of the mouth caused by an overgrowth of the yeast organism Candida albicans. Thrush usually begins on
the tongue and inside the cheeks and may spread to the palate, gums, tonsils, and
throat. In severe cases, the infection may spread to the larynx (voice box),
digestive tract, respiratory system, and skin.

Causes

Many microorganisms, including yeast and bacteria, live in the mouth. Thrush occurs when the normal balance of these organisms is upset. This allows an overgrowth of Candida to occur.

Risk Factors

Risk factors for developing thrush include age (infants, toddlers, and the
elderly); a weakened immune system from human immunodeficiency
(HIV) virus infection, acquired immunodeficiency
syndrome (AIDS), cancer, or medical treatments for cancer,
such as chemotherapy; stress; prolonged illness; use of antibiotics;
use of oral or inhaled corticosteroids; diabetes; hormonal
changes, such as those associated with pregnancy or the use of birth control pills; wearing dentures; conditions that cause a dry mouth; and
smoking.

Symptoms

The symptoms of thrush, which occur in the mouth, include white, raised
patches; red, slightly raised patches; discharge with a curdlike appearance (like
cottage cheese); thick, dark brownish coating in the mouth; dry mouth; and
fissures or cracks in the mouth. If the infection spreads into the esophagus, one
may also experience difficulty or pain with swallowing or a sensation of something
“stuck” in the throat. If thrush spreads systemically, one may develop a
fever.

Screening and Diagnosis

A doctor will ask about symptoms and medical history and will examine the patient’s mouth. A sample of cells from the affected area may be scraped off and examined under a microscope.

Treatment and Therapy

The goal of treatment is to restore the normal balance of bacteria and yeast in
the mouth. Treatments may include antifungal medications such as lozenges, troches
(a type of lozenge that dissolves in the mouth), tablets, or oral rinses;
medications that are active against yeast, such as nystatin (Bio-Statin and
Nilstat), clotrimazole (Lotrimin and Mycelex), miconazole, and gentian violet;
and, for breast-feeding mothers of infants with thrush, a topical antifungal
medication placed on the woman’s nipples to reduce the infant’s infection.

Oral hygiene practices that may aid in healing include rinsing one’s mouth with warm salt-water and gently scraping off patches with a toothbrush. Finally, underlying conditions that may contribute to thrush can be identified and treated.

Prevention and Outcomes

Preventive measures can be taken to reduce the risk of thrush. Thrush in adults is often associated with AIDS, so persons with thrush should obtain a blood test for HIV and follow recommended prevention guidelines, such as using condoms and other protection and avoiding needles except under sterile conditions.

Persons who are at high risk for or who are prone to thrush may be given an antifungal medication as a preventive measure. If prone to thrush, one should avoid overuse of mouthwashes and mouth sprays, which can upset the normal balance of yeast and bacteria in the mouth. If a baby is prone to thrush and if that baby drinks from a bottle, the baby should drink from the bottle with disposable nipples.

One should avoid unnecessary use of antibiotics; if avoiding antibiotics is not
an option, one should consider eating yogurt or using acidophilus tablets
(probiotics) during antibiotic treatment and for several
weeks thereafter. One should decrease his or her intake of sugar and
yeast-containing foods and beverages, such as bread, wine, and beer, and, if using
a cortisone inhaler, should rinse the mouth thoroughly after each use.

Bibliography

Greenspan, Deborah, and John S. Greenspan. “HIV-related Oral Disease.” The Lancet 348 (September, 1996): 729-733.

Langlais, Robert P., and Craig S. Miller. Color Atlas of Common Oral Diseases. 4th ed. Philadelphia: Lippincott Williams & Wilkins, 2009.

Mandell, Gerald L., John E. Bennett, and Raphael Dolin, eds. Mandell, Douglas, and Bennett’s Principles and Practice of Infectious Diseases. 7th ed. New York: Churchill Livingstone/Elsevier, 2010.

Martin, Jeanne Marie. Complete “Candida” Yeast Guidebook: Everything You Need to Know About Prevention, Treatment, and Diet. Rev. ed. New York: Three Rivers Press, 2000.

Ohnmacht, Galen A., et al. “A Prospective, Randomized, Double-Blind, Placebo-Controlled Trial Evaluating the Effect of Nystatin on the Development of Oral Irritation in Patients Receiving High-Dose Intravenous Interleukin-2.” Journal of Immunotherapy 24, no. 2 (March/April, 2001): 188-192.

Winn, Washington C., Jr., et al. Koneman’s Color Atlas and Textbook of Diagnostic Microbiology. 6th ed. Philadelphia: Lippincott Williams & Wilkins, 2006.