Oral thrush is a common fungal infection of the mouth that can cause white or yellow patches on the tongue, gums, or inner cheeks. It is caused by the fungus Candida albicans, which is normally present in the mouth in small amounts. However, certain factors can cause the fungus to overgrow, leading to oral thrush.
Oral thrush is most common in infants, the elderly, and people with weakened immune systems. It can also be caused by certain medications, such as antibiotics and steroids. Symptoms of oral thrush include white or yellow patches on the tongue, gums, or inner cheeks; a burning or stinging sensation in the mouth; difficulty swallowing; and a loss of taste.