Psoriasis is an immune-mediated disease that causes your body to make new skin cells too quickly. As a result, thick, scaly rashes called plaques form on the skin, especially on knees, elbows, the lower back, and the scalp. Called “plaque psoriasis,” this form of the condition affects 90% of people with the disease.
Another common form of psoriasis appears as small red dots or blotches spread over large areas. Psoriasis is often accompanied by itching, stinging, or burning and can increase the risk of developing serious diseases, such as psoriatic arthritis or diabetes.