Callus is also called callus, the scientific name is callus, mainly occurs in the palm of the hand or foot parts of the yellow hyperkeratotic plaque, is a kind of skin compensatory hyperplasia. The main reason for the friction stimulation caused by, for example, often walking, wearing uncomfortable shoes, and then as often as the bar movement, the palm of the hand will also appear keratinized thickened patches, sometimes overgrowth, causing pain, treatment can be hot water soaking, softened with a razor blade to remove the thickened keratin, you can also apply topical compound lactic acid cream or salicylic acid cream, to soften and exfoliate the role of the keratin.