What is the difference in appearance between lichen planus and leukoplakia?

White patches : Leukoplakia means "white plaque" or white patch. Lichen planus is an autoimmune reaction between cell layers of the oral mucosa usually with a white, lace like appearance in the cheeks. Lichen planus is usually painless, but can be tender and usually treated with topical steroids if at all. A leukoplakia is more of a generic term for a white patch, where as lichen planus is a diagnosis.

Subset of other: Leukoplakia is a broad category of white spot or lesion. Lichen planus is a white lesion that usually appears lacy-like on the inside of your cheeks. Either/both should be evaluated and monitored by your dentist as they can become pre-cancerous.

Diff can be serious: Lichen planus can be scraped off the mucosa, leukoplakia can not. Also sometimes leukoplakia can be pre malignant, much more serious lesion.