If you have a compromised immune system due to prolonged antibiotic or oral steroid use, you may be at risk for a mouth yeast infection. These oral yeast infections are referred to as thrush. Oral thrush is caused by an over abundance of the yeast like fungi Candida. Candida is present in everyone’s system but in those with weakened immune systems, the Candida can grow out of control and cause an oral thrush infection.

Oral candidacies are an infection of yeast fungus, Candida albicans, in the mucous membranes of the mouth. Oral thrush refers to short-term candidacies in the mouths of babies, whilst if happening in the mouth or throat of adults it may also be termed candidacies.
Symptoms:
Oral infections of Candida generally appear as thick white or cream-colour deposits. [...]