Oral thrush also called oral candidiasis or oropharyngeal candidiasis - is a medical condition in which a yeast-shaped fungus called Candida overgrows in the mouth and throat. Candida is normally present in the mouth, digestive tract, and skin of most healthy people. The immune system and the body's normal bacteria usually keep Candida in balance. When this balance is interrupted, it can result in an overgrowth of the Candida fungus, causing thrush, a yeast infection of the mouth or throat.
Oral thrush causes creamy white lesions, usually on your tongue or inner cheeks. Sometimes oral thrush may spread to the roof of your mouth, your gums or tonsils, or the back of your throat.
Although oral thrush can affect anyone, it's more likely to occur in babies, the elderly, and in people with suppressed immune systems or certain health conditions, or those who take certain medications. Oral thrush is a minor problem if you're healthy, but if you have a weakened immune system, symptoms of oral thrush may be more severe and difficult to control.
Thrush is not the same as a vaginal yeast infection. However, the Candida fungus also causes diaper rash, but diaper rash occurs on a child's rear end, genitals, and inner thighs, while oral thrush occurs in the mouth and throat. Adults may get yeast infections in areas of overlapping skin, such as underneath breasts or in skin folds like creases in skin due to fatty tissue.