Psoriasis is a persistent, long-lasting (chronic) disease that is not contagious. While the exact cause of psoriasis is unknown, scientists believe the immune system mistakenly activates a reaction in the skin cells that causes itchy skin spots, patches, and lesions to form.
Generally, there are 5 major types you should know about.
This is the most common form of psoriasis. It's characterized by raised, inflamed, red lesions covered by silvery white scales. Typically, it's found on the elbows, knees, scalp, and lower back. About 80% of those who have psoriasis have this type.
Guttate psoriasis often starts in childhood or young adulthood. It appears as small, red, individual spots on the skin of the torso, arms, and legs. These spots are not usually as thick as plaque lesions.
Found in the armpits, groin, under the breasts, and in other skin folds around the genitals and the buttocks. This type of psoriasis appears as bright-red lesions that are smooth and shiny.
Primarily seen in adults, pustular psoriasis is characterized by white blisters of noninfectious pus surrounded by red skin. It may either be localized to certain areas of the body, such as the hands and feet, or covering most of the body.
A particularly inflammatory form of psoriasis affecting most of the body surface, it is characterized by periodic, widespread, fiery redness of the skin and the shedding of scales in sheets.