Psoriasis is an inflammatory skin condition. There are five types, each with unique signs and symptoms. Between 10% and 30% of people who develop psoriasis get a related form of arthritis called “psoriatic arthritis,” which causes inflammation of the joints.

Plaque psoriasis is the most common type of psoriasis. About 80% of people who develop psoriasis have plaque psoriasis, which appears as patches of raised, reddish skin covered by silvery-white scale. These patches, or plaques, frequently form on the elbows, knees, lower back, and scalp. However, the plaques can occur anywhere on the body.

The other types are guttate psoriasis (small, red spots on the skin), pustular psoriasis (white pustules surrounded by red skin), inverse psoriasis (smooth, red lesions form in skin folds), and erythrodermic psoriasis (widespread redness, severe itching, and pain).

Regardless of type, psoriasis usually causes discomfort. The skin often itches, and it may crack and bleed. In severe cases, the itching and discomfort may keep a person awake at night, and the pain can make everyday tasks difficult.

Psoriasis is a chronic, meaning lifelong, condition because there is currently no cure. People often experience flares and remissions throughout their life. Controlling the signs and symptoms typically requires lifelong therapy.

Treatment depends on the severity and type of psoriasis. Some psoriasis is so mild that the person is unaware of the condition. A few develop such severe psoriasis that lesions cover most of the body and hospitalization is required. These represent the extremes. Most cases of psoriasis fall somewhere in between.