Malassezia Dermatitis is a fancy way of saying yeast infection of the skin. Small amounts of yeast on the skin is normal, but when the conditions change yeast may overgrow and cause odor, itchiness, rashes, and skin thickening in some cases. To diagnose we use a few different tests, like the impression smear. Treatment is fairly simple, sometimes as simple as a medicated shampoo. In more serious cases an antimicrobial may be prescribed as well.