Oral thrush (also known as candidiasis) is an infection of naturally occurring fungus in the mucus membranes that line the mouth and tongue.

Causes and Risk Factors

Thrush is caused by the fungus candida—the same fungus that causes yeast infections in the vagina. Small amounts of the fungus live naturally in the body and are normally regulated by the immune system. The infection begins when a person’s immune system is compromised.

People more susceptible to thrush include:

  • infants
  • elderly
  • diabetics
  • cancer patients receiving chemotherapy
  • organ transplant recipients receiving immune suppressing drugs
  • HIV or AIDS patients
  • those taking antibiotics for a long period of time
  • those taking steroid medications

Symptoms and Treatments

Thrush appears as white lesions in the mouth and on the tongue that can slowly grow in size and number. The lesions can sometimes spread to the roof of the mouth, gums, tonsils, and back of the throat. The lesions also bleed easily. Other symptoms may include:

  • pain in the mouth
  • cracking at the corner of the mouth
  • cottony feeling in the mouth
  • loss of taste

Because of the distinct appearance of thrush lesions, a doctor can diagnose the infection during a physical examination. If a doctor is unsure, a culture sample is usually taken.

Thrush is easily treated with antibiotics or antifungal mouthwash. Eating yogurt and rinsing your mouth with a diluted hydrogen peroxide solution can also help. Treatment in infants is not needed because it generally disappears within two weeks.