Your doctor will usually be able to diagnose oral trush just by a simply examination of yours or your child’s mouth. The infection usually causes distinctive white lesion on the mouth, tongue or cheeks.
However, sometimes they may examine a small sample of the lesions under a microscope. If oral trush is found in teenagers or adults, the doctor may also conduct further physical exams or ask for blood tests to asses if there is another underlying cause of the symptoms of oral trush, such as diabetes or nutritional deficiencies.
In more serious cases where it is suspected that oral trush has spread to the esophagus, your doctor may ask for a throat culture. This is where a sample of tissue is taken by swabbing the back of the throat with sterile cotton, and then examined to see what is causing the symptoms. The may also conduct an endoscopic exam to examine your esophagus, stomach and the upper part of the small intestine (the duodenum), by using a small camera attached to the tip of a flexible tube. X-rays of the esophagus can also help with the diagnosis process.