With leukoplakia (loo-koh-PLAY-key-uh), thickened, white patches form on your gums, the insides of your cheeks, the bottom of your mouth and, sometimes, your tongue. These patches can't be scraped off.
Doctors don't know what causes leukoplakia but consider chronic irritation from tobacco — whether smoked, dipped or chewed — to be the main culprit in its development.
Most leukoplakia patches are noncancerous (benign), though some show early signs of cancer. Cancers on the bottom of the mouth can occur next to areas of leukoplakia. And white areas mixed in with red areas (speckled leukoplakia) may indicate the potential for cancer. So it's best to see your dentist or primary care professional if you have unusual, persistent changes in your mouth.
A type of leukoplakia called hairy leukoplakia, sometimes called oral hairy leukoplakia, primarily affects people whose immune systems have been weakened by disease, especially HIV/AIDS.