Psoriasis is an autoimmune condition that causes inflammation of the skin. It occurs because an overactive immune system speeds up skin cell growth. That creates areas of thick, discolored-looking skin called plaques. On people with light-colored skin, the plaques look pink or reddish. On darker skin, they tend to be dark purple or brown. Like eczema, psoriasis isn’t contagious. You can’t get it from someone else. Triggers for flare-ups include sunburn, vaccinations, stress, and infections. Psoriasis affects fewer people than eczema, but it’s still common. According to the National Psoriasis Foundation, more than 7.5 million people in the U.S. have psoriasis. There’s no cure for psoriasis, but treatment can help you manage symptoms when it flares.