Calluses and Corns (Tylomas; Helomas; Clavi) By James G H Dinulos, MD, Geisel School of Medicine at Dartmouth Reviewed / Revised May 2023 View Patient Education Symptoms and Signs Diagnosis Treatment Key Points Topic Resources Corn (Little Toe) Callus (Heel) Calluses and corns are circumscribed areas of hyperkeratosis at a site of intermittent pressure or friction.