Psoriasis turns your skin cells into Type A overachievers: They grow about five times faster than normal skin cells -- and your body can't keep up. The old ones pile up instead of sloughing off, making thick, flaky, itchy patches.
Why do these cells go a little haywire? There's more going on under the surface of this skin disease.
Researchers think something sets off your immune system. The exact reason is a mystery, but it's likely a combination of genetics and triggers.