Oral thrush and leukoplakia cause white bumps on the side of the tongue, as stated by WebMD. Oral thrush develops as a result of candida yeast, while leukoplakia is a largely harmless cell overgrowth.
Oral thrush is a condition that produces white patches throughout the mouth, including the tongue. It is common in infants, people who wear dentures and those who have a weakened immune system because of conditions like HIV/AIDS, chemotherapy or diabetes.
Leukoplakia arises when the cells on the tongue grow too fast. Although it is not a dangerous condition on its own, it can act as a precursor to oral cancer. Therefore, those who experience it should look out for other signs and discuss the matter with their dentist.