Psoriasis is an immune-mediated disease that causes inflammation in the body. This skin disorder causes skin cells to multiply up to 10 times faster than normal and makes the skin build up into bumpy red patches covered with white scales. Psoriasis is not contagious but these patches can appear anywhere on the body, on the eyelids, ears, lips, skin folds, hands, feet, and nails. Raised plaques and scales on the skin are the visible signs of inflammation caused by psoriasis.