Thrush

Description

Thrush (Candidiasis)is a superficial yeast infection of the mouth and throat. Other names for this common condition include oral candidiasis, oropharyngeal candidiasis, pseudomembranous candidiasis, and mycotic stomatitis . Thrush is characterized by the presence of thick, curd-like white patches on the tongue and inside of the cheeks. The underlying tissue is red and inflamed. The roof and floor of the mouth and the gums may also be affected. Thrush may be easily diagnosed by the appearance of the lesion. To confirm the diagnosis, a sample for microscopic analysis may be taken by scraping the lesion with a tongue depressor.

Thrush itself is a harmless infection; however, Candida may spread throughout the body (systemic infection) to the kidneys, lungs, joints, bones, and brain and spinal cord (central nervous system). A systemic infection can be very serious, especially in a cancer patient with a weakened immune system.

Causes

Thrush may be caused by several different species of Candida. Thrush rarely occurs in healthy persons. Three factors contribute to infection Candida : impairment of the immune system (immunosuppression), injury to the tissues (mucosa, mucous membranes) of the mouth, and decrease in saliva flow. In addition, thrush can occur following treatment with antibiotics , when normal mouth (oral) bacteria have been eliminated allowing for over-growth of Candida. In addition to standard intravenous chemotherapeutic agents, corticosteroids , cyclosporine A, and interleukin-2 suppress the immune system, placing the patient at a higher risk of infection. Patients who have been treated with myeloablative therapy, as in preparation for bone marrow transplantation , are at a very high risk of infection. In addition, certain cancers predispose the patient to developing candidiasis, including multiple myeloma , chronic lymphocytic leukemia , hairy cell leukemia , Hodgkin's disease , and adrenal tumors . Malnutrition, which is not uncommon among cancer patients, also suppresses the immune system.

Patients undergoing chemotherapy and/or head and neck radiation are at an increased risk of developing thrush. These therapies target the rapidly dividing cancer cells. The mucosal cells which line the mouth are also rapidly dividing. The skin and mucous membranes make up the first line of defense against invading organisms and, when damaged by cancer treatments, these tissues become susceptible to infection. Chemotherapy can decrease the number of neutrophils, a type of white blood cell, causing a condition called neutropenia . Neutropenia significantly increases the patient's risk of infection. Radiation therapy reduces the number of white blood cells which impairs the immune system.

Thrush is a temporary side effect of cancer treatment. It can take up to a year for the immune system to recover from intensive radiation therapy. Thrush that is related to the cancer may be persistent or recurrent.

Treatments

Thrush is usually treated with the antifungal drugs clotrimazole, nystatin, or amphotericin. Clotrimazole is taken as a lozenge which is allowed to dissolve slowly in the mouth. The commonly used nystatin is taken as a solution that is swished through the mouth, although recent studies have shown that nystatin may not be as effective as the newer antifungals. Amphotericin is taken as a tablet or solution. The duration of treatment may range from five to 14 days. Often, thrush resolves with local treatment alone, however, systemic medication (such as fluconazole) may be used in some cases.

The patient with thrush should faithfully conduct a daily oral hygiene routine consisting of tooth brushing two to three times, flossing once, utilizing medicated rinses as prescribed by the physician. Brushing and flossing should be performed carefully to prevent damage to the weakened oral mucosa. Dentures and other mouth appliances, which can harbor the yeast and be a source for possible reinfection, need to be disinfected.

Alternative and complementary therapies

Because there is the risk that Candida may spread and cause a serious systemic infection, thrush should be treated with antifungal drugs. The patient with thrush can help fight the infection by eating a well-balanced diet to counteract immunosuppression caused by malnutrition. Nutritional supplements may also be useful. Some practitioners claim that herbs (such as goldenseal or garlic) can be used to kill yeasts and boost the immune system. However, these complementary therapies should be discussed with the patient's physician because of thrush's potentially serious threat to the cancer patient.

See Also Chemoprevention

Resources

ORGANIZATIONS

The Cancer Center at the University of Virginia. "What to do when you have taste changes." <http:www.med.virginia.edu/medcntr/cancer/tastechanges.html>. 5 July 2001.

National Cancer Institute. CancerNet. <http://www.nci.nih.gov> 5 July 2001.

OTHER

On-line Medical Dictionary "Candidiasis" <http://www.graylab.ac.uk/cgi-bin/omd?query=thrush> 5 July 2001.

Belinda Rowland, Ph.D.

KEY TERMS

Immunosuppression

—Impairment or weakening of the immune system caused by chemotherapy or radiation therapy.

Neutropenia

—The condition of having low numbers of the white blood cells called neutrophils. Oral —Pertaining to the mouth.

Systemic

—Affecting the entire body.

Thrush

What Is Thrush?

How Is Thrush Diagnosed and Treated?

Resource

Thrush is an infection that causes raised white patches in the mouth and throat that can look like cottage cheese. It is caused by the Candida albicans fungus that aho causes diaper rash and vaginal yeast infections.

KEYWORDS

for searching the Internet and other reference sources

Candidiasis

Infection

Moniliasis

Mycotic stomatitis

What Is Thrush?

Candida albicans is a single-celled fungus that is a natural inhabitant of the mouth. Usually, the body maintains a natural balance of microbes* in the mouth. But if that natural balance has been disturbed, Candida and other fungi may begin to grow in the warm moist environment of the mouth and throat. Other names for thrush are oral candidiasis (kan-di-DY-a-sis) and oral moniliasis (mon-i-LY-a-sis).

* microbes

are small organisms that usually can be seen only under a microscope. They include bacteria, protozoa, and fungi.

Thrush and the immune system

Thrush is common in newborns. In older children, and adults, it may be a sign of an immune system disorder. People whose immune systems have been damaged by the AIDS virus, for example, may develop thrush. People who are treated with antibiotics for bacterial infections and people who use steroid inhalers for asthma may also develop thrush.

Neonatal thrush

Infants may get thrush during childbirth, if their mothers have vaginal yeast infections, or they may get thrush from bottles or nipples or family members with contaminated hands. Thrush looks like white patches of cottage cheese on the tongue, palate (roof of the mouth), inner cheeks, or throat. If the white patches of thrush are scraped, however, the sores will bleed, and infants may refuse to suck because of pain in the mouth. Candida also causes diaper rash, but those sores are reddish rather than white.

How Is Thrush Diagnosed and Treated?

Thrush usually goes away by itself. Because thrush may be a sign of an immune system disorder, however, it is important to check with a doctor or dentist, who may identify the yeast under a microscope, check for possible causes, and suggest ways to prevent its recurrence.

Thrush usually is treated by prescription medication, taken orally or applied directly to the sores, and by careful hygiene, which includes frequent hand washing, frequent diaper changes, and use of mouth washes.

See also

Asthma

Fungal Infections

Yeast Infection, Vaginal

Resource

The U.S. Centers for Disease Control and Prevention (CDC) posts ABCs of Safe and Healthy Child Care at its website, which includes a fact sheet about thrush. http://www.cdc.gov/ncidod/hip/abc/facts43.htm

Turdidae (blackbird, bluethroats, chats, nightingales, redstarts, rubythroats, shortwings, thrushes, wheatears; class Aves, order Passeriformes) A family of small to medium birds, most of which are brown, grey, black, olive, blue, or white, usually contrasting. Some Turdus species (of which there are about 63) have black-spotted, white under-parts. Some of the 29 Zoothera species have spotted under-parts or wing bars and many have distinctive, white, under-wing stripe. Most wheatears (18 species of Oenanthe) have distinctive white rumps, and black tails. Redstarts (11–13 species of Phoenicurus) have orange bellies, black throats, and black, blue, or grey heads and backs; females are duller brown but both sexes have distinctive orange-red tails and rumps. Turdids have medium-length, slender to stout bills, short and rounded to long and pointed wings, and short to long tails, some forked. Their legs are of medium length, and are ‘booted’ (have no scales). They are arboreal and terrestrial, inhabiting forests, open country, deserts, and cultivated land, and feed on animal and vegetable matter. They nest in trees and bushes, on the ground, or in tree holes or rock cavities. The 10–12 species of Monticola (rock thrushes) inhabit open, rocky areas, scrub, and dry forest, and nest in rock crevices. Luscinia megarhynchos (nightingale) is a secretive bird noted for its song (many or all of the 7–18 Luscinia species (bluethroats, nightingales, and rubythroats) are often placed in the genus Erithacus). Shortwings (six species of Brachypteryx) are robin-like birds with short wings and short tails, skulking in habit, and live in dense forest undergrowth. The 10 species of chats, of which many are migratory, comprise the genus Saxicola. Turdus merula (blackbird) and T. philomelos (song thrush) have been introduced to New Zealand which otherwise is the only part of the world from which Turdus species are absent. There are about 50 genera in the family, with about 312 species, found world-wide.

Thrush

Thrush, or oropharyngeal candidiasis , is an infection of the mouth and throat caused by the fungus Candida, a genus of yeast . This microorganism is naturally present on the skin and mucous membranes, but overgrowth can cause disease. Candidiasis is not considered communicable because the microorganism is ubiquitous (common and widespread).

Symptoms of thrush include cottage cheese-like white patches in the mouth and throat, with raw areas underneath. Esophageal involvement may result in difficulty in swallowing, nausea, vomiting, and chest pain. Candidiasis is confirmed by culture from a swab of the infected tissue.

Proliferation of Candida is most often the result of a weakened immune system . Candidiasis is one of the most common and visible opportunistic infections that strike people with AIDS , chemotherapy patients, and other immunocompromised individuals. Many AIDS patients have been first diagnosed after they, or their dentists, noticed a thrush infection. In individuals with normal immune systems, candidiasis may be associated with antibiotic use. Infants, diabetics, smokers, and denture wearers are particularly susceptible to thrush.

In addition to causing thrush, Candida may affect the gastrointestinal tract or genitals. The microorganism may also enter the bloodstream, either via surgery or catheterization, or through damage to the skin or mucosa. If the immune system is unable to clear the fungus from the bloodstream, a dangerous systemic infection may occur, resulting in endocarditis, meningitis , or other serious problems.

Antifungal medications such as fluconazole and clotrimazole are generally effective in treating candidiasis. However, drug-resistant strains of Candida are becoming increasingly prevalent, and recurrence is common. This situation is driving research into new therapies and potential vaccines.

See also Bacteria and bacterial infection; Fungal genetics; Fungi; Fungicide; Immunodeficiency; Immunosuppressant drugs; Infection and resistance; Infection control; Microbial flora of the oral cavity, dental caries; Yeast genetics; Yeast, infectious

thrush¹ / [unvoicedth]rəsh/ • n. a small or medium-sized songbird (Turdus and other genera), typically having a brown back, spotted breast, and loud song. The thrush family (subfamily Turdinae, family Muscicapidae) includes the chats, robins, bluebirds, blackbirds, nightingales, redstarts, and wheatears. thrush² • n. 1. infection of the mouth and throat, producing whitish patches, caused by a yeastlike fungus (genus Candida), esp. C. albicans Also called candidiasis. ∎  infection of the female genitals with the same fungus. 2. a chronic condition affecting the frog of a horse's foot, causing the accumulation of a dark, foul-smelling substance. Also called canker.