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Oral Thrush

What is oral thrush?

Oral thrush occurs when a yeast infection develops on the inside of your mouth and on your tongue. This condition is also known as oropharyngeal candidiasis.

The Candida albicans fungus causes oral thrush. A small amount of this fungus normally lives in your mouth without causing harm. However, when the fungus begins to grow uncontrollably, an infection can develop in your mouth.

Oral thrush most often occurs in infants and toddlers. It causes white bumps to form on the inner cheeks and tongue. These growths usually go away once treatment is received.

Oral thrush is typically a mild infection that rarely causes complications. However, the condition can be problematic for those with weakened immune systems.

Pictures of thrush

What are the symptoms of oral thrush?

In its initial stages, oral thrush may not cause any symptoms. However, as time passes and the fungus continues to grow, the following symptoms may develop:

  • creamy white bumps on the tongue, inner cheeks, gums, or tonsils
  • slight bleeding when the bumps are scraped
  • pain at the site of the bumps
  • dry, cracked skin at the corners of the mouth
  • difficulty swallowing

In infants, oral thrush may cause:

  • difficulty feeding
  • fussiness
  • irritability

Babies with oral thrush can pass the infection on to their mothers during breastfeeding. Mothers and their infants can get caught in a cycle in which they infect and reinfect one another. If you’re breastfeeding and your breasts become infected with the fungus, you may experience:

What causes oral thrush?

Oral thrush occurs when the C. albicans fungus begins to grow out of control. Normally, the immune system uses good microorganisms to keep C. albicans and other bad microorganisms under control. When this balance is disrupted, however, harmful bacteria and fungi begin to multiply. This causes an infection to develop.

Oral thrush can occur when your immune system is weakened by certain medications that reduce the number of good microorganisms that would naturally prevent infection. Cancer treatments, including chemotherapy and radiation, can also damage or kill healthy cells. This makes you more susceptible to oral thrush and other infections.

Diseases that attack your immune system, such as HIV, AIDS, and leukemia, also increase your risk for oral thrush. Diabetes, another illness that affects your immune system, can contribute to oral thrush as well. If you have uncontrolled diabetes, you likely have a high level of sugar in your saliva. It’s thought that C. albicans can then use this extra sugar to fuel its growth in your mouth.

In newborns, oral thrush can be contracted at birth. The same fungus that causes oral thrush also causes yeast infections, so pregnant women with a vaginal yeast infection can pass the infection on to their baby during delivery.

Who's at risk for oral thrush?

Babies and toddlers have the highest risk of developing oral thrush. However, the infection can also affect people who have a weakened immune system. You may have a weak immune system and be more at risk for oral thrush if you:

How is oral thrush diagnosed?

Your doctor will probably be able to diagnose oral thrush simply by examining your mouth and tongue for the characteristic white bumps.

In some cases, your doctor may take a biopsy to confirm the diagnosis. A biopsy involves scraping off a very small portion of a bump in the mouth. The sample is then sent to a laboratory, where it will be tested for the presence of C. albicans.

If your esophagus has become infected with oral thrush, your doctor likely will perform more procedures to ensure an accurate diagnosis. These can include a throat culture and an endoscopy.

During a throat culture, your doctor will use a cotton swab to take a tissue sample from the back of your throat. The sample will then be sent to a laboratory for analysis.

Endoscopy involves the use of an endoscope, which is a thin tube with an attached light and camera. Your doctor will insert the endoscope through your mouth and into your esophagus to examine the affected area. They may also remove a sample of tissue for inspection.

How is oral thrush treated?

Treatment for oral thrush varies depending on your age and overall health. The purpose of treatment is to prevent the growth and spread of the fungus.

Medical treatment for oral thrush may consist of:

  • fluconazole, which is an oral antifungal medication
  • a clotrimazole lozenge, which is an antifungal medication that you leave in your mouth until it dissolves
  • nystatin, which is an antifungal mouthwash that you swish around in your mouth and then swallow
  • itraconazole, which is an oral antifungal medication used for people who are resistant to initial treatments or who have HIV or AIDS
  • amphotericin B, which is a drug used to treat severe infections

An at-home regimen for treating oral thrush should include:

  • brushing your teeth with a soft toothbrush to avoid scraping the lesions
  • replacing your toothbrush every day until the infection goes away
  • not using mouthwashes or sprays
  • using a saltwater mixture to rinse your mouth
  • maintaining appropriate blood sugar levels if you have diabetes
  • eating unsweetened yogurt to help restore and maintain healthy levels of good bacteria

When a breastfeeding infant has oral thrush, both the mother and infant should be treated to prevent a cycle of reinfection. Treatment in these cases may include:

  • using an antifungal medication for the baby and an antifungal cream for the mother’s breasts
  • rinsing pacifiers, bottle nipples, and all pieces of a breast pump in a solution of half water and half vinegar and allowing the items to air dry
  • using nursing pads to prevent the fungus from spreading to clothes

Once treatment begins, oral thrush usually goes away within a couple of weeks. However, the infection may return again in the future. A complete cure is more likely if you have a healthy immune system and are free of other diseases.

What are the potential complications of oral thrush?

Oral thrush rarely causes complications in people with healthy immune systems. People whose immune systems are weakened by certain diseases or medical treatments are the most likely to experience complications. If you have a weak immune system, the fungus may enter your bloodstream and spread throughout your body. This can eventually cause problems in various body structures, including the brain, heart, and liver.

Infants who develop oral thrush also may get a severe diaper rash.

How can oral thrush be prevented?

You can reduce your risk for oral thrush by following these simple routines:

  • Practice good oral hygiene by brushing your teeth. You should also floss daily. This is especially important if you have diabetes or wear dentures.
  • Rinse out your mouth after using a corticosteroid inhaler.
  • Add yogurt to your diet whenever you take prescribed antibiotics.
  • Promptly treat a vaginal yeast infection, especially if you’re pregnant.

Content licensed from:

Written by: Anna Giorgi
Medically reviewed on: Feb 16, 2016: Karen Richardson Gill, MD, FAAP

This feature is for informational purposes only and should not be used to replace the care and information received from your health care provider. Please consult a health care professional with any health concerns you may have.
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