Clinical terms. They are not a true diagnosis. They are clinical terms that mean a red (erythro) or white (leuko) patch.
Leuk vs eryth. Leukoplakia is literally "white patch. Erythroplakia is red. Caused by blood in the lesion.
Leuko/Erythroplakia. I have attached links to 2 really thorough articles on both of these topics- http://tinyurl. Com/3sbuyyf http://en. Wikipedia. Org/wiki/erythroplakia.