Painless white spots in the mouth may be caused by candidiasis, oral lichen planus and leukoplakia. A main cause of these white spots forming in different areas of the mouth is candidiasis or oral thrush, which develops due to the candida fungus. Oral lichen planus is a condition the affects the mucosal membrane of the mouth, while the cause of leukoplakia is not entirely known but may be related to other factors, according to Mayo Clinic.
Oral thrush may more commonly affect young children, but adults may also develop this condition if their immune systems are compromised. The candida fungus can develop and grow in the mouth due to different factors, such as medical conditions and certain drugs. These different factors can include cancer, antibiotics and dry mouth, reports WebMD. Thrush appears as whitish patches or spots on the tongue, around the throat and cheek areas.
Although the direct cause of oral lichen planus is unknown. it is believed that it may be related to an autoimmune issue, relates the American Academy of Dermatology. Oral lichen planus can have the appearance of white lines, spots, patches that can be on the inner cheek and tongue. This is a chronic condition that has no cure but can be controlled.
Leukoplakia is another condition that has an unknown cause. However, the are different forms of this condition that may be linked to either tobacco use or infections. The white or gray patches that form with leukoplakia can be irregular in shape. Most of these patches can be benign, but others may present early signs of cancer, notes Mayo Clinic.