Plaque psoriasis is a long-lasting autoimmune disease that causes cells to reproduce very quickly, leading to the formation of thick patches (plaques) on the skin. These plaques appear as raised, inflamed, and scaly patches of skin that may also be itchy and painful. On Caucasian skin, plaques typically appear as raised, red patches covered with a silvery white buildup of dead skin cells or scale. On skin of color, the plaques may appear darker and thicker and more of a purple or grayish color or darker brown. Plaques can appear anywhere on the body, although they most often appear on the scalp, knees, elbows, and torso. Plaques generally appear symmetrically on the body, affecting the same areas of the body on the right and left sides.

Plaque psoriasis is not contagious, and it is not caused by poor hygiene. The exact cause of plaque psoriasis is unknown, but it is thought to be an immune system problem where the immune response overreacts, causing inflammation, which leads to new skin cells growing too fast. Plaque psoriasis flare-ups differ from person to person, and common triggers may include certain foods or drinks, certain prescription medications, dry skin, emotional stress, skin injuries, and sun damage.

There is no cure for plaque psoriasis, but there are treatments available to help manage the symptoms. Treatment options include topical creams and ointments, light therapy, oral medications, and biologic drugs. It is important to work with a healthcare provider to determine the best treatment plan for each individual case.