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Oral Thrush

Girl with oral thrush

What is oral thrush?

Oral thrush is a yeast infection that develops inside your mouth. It may also be called oral candidiasis.

What causes oral thrush?

Oral thrush is caused by a yeast called Candida Albicans (C. Albicans) which is a type of fungus.

C. Albicans is a normal inhabitant of your mouth and usually causes no harm because it is kept in check by beneficial bacteria. Our immune system is responsible for maintaining this balance.

If our immune system becomes compromised in some way or something disrupts the quantities of beneficial bacteria (such as antibiotics), C.Albicans can grow out of control and cause thrush.

Oral thrush is more likely to develop in the very young or very old.

Other people who are at risk of oral thrush include those:

  • Receiving broad-spectrum antibiotics (these can alter the balance of beneficial bacteria)
  • Prescribed oral corticosteroids or prednisone
  • Receiving chemotherapy or radiation therapy for cancer as both of these treatments can damage healthy cells
  • With certain nutritional deficiencies, such as iron deficiency or vitamin B deficiency
  • With conditions such as HIV, leukemia or other types of cancer that weaken the immune system
  • With dentures or injury or trauma to the mouth
  • With poorly treated diabetes
  • With persistent dry mouth due to disease or certain medications (such as antihistamines, diuretics)
  • Who smoke
  • With thrush elsewhere (eg, vaginal thrush infections during pregnancy can be passed to newborns during birth)

What are the symptoms of oral thrush?

Initially, symptoms may be mild and not easily noticed. As the infection worsens, creamy white or yellow spots or patches may become noticeable on the tongue, insides of the cheeks, tonsils and sometimes the gums and lips. These patches may bleed if scraped.

Other symptoms may include:

  • A bad taste in the mouth or loss of taste
  • A cotton-wool like sensation in the mouth
  • Soreness or burning inside the mouth
  • Difficulty swallowing
  • The skin at the corners of your mouth may become dry and cracked

C. Albicans can also spread to other people who come into contact with the infection (for example, the nipples of mothers who are breastfeeding babies with oral thrush may become infected), although they may not develop symptoms if their immune system is strong.

How is oral thrush treated?

Oral thrush may be treated using oral antifungals, antifungal lozenges, or antifungal mouthwashes. The infection usually resolves within two weeks.

It is not uncommon for infants to have several episodes of thrush in their first year of life but adults with recurring thrush should see their doctor for further investigations for any underlying medical conditions that may be contributing to thrush.