Psoriasis is a common skin condition that speeds up the life cycle of skin cells. This causes cells to build up rapidly on the surface of the skin forming itchy and sometimes painful scales and red patches. Psoriasis is a chronic disease that often comes and goes, but is not contagious. Common locations for psoriasis to develop are the scalp, face, hands, feet, nails, genitals, and any skin folds such as armpits and under the breasts. There are five main types of psoriasis:

• Plaque psoriasis, the most common form of the disease, appears as raised, red patches covered with a silvery white buildup of dead skin cells. These patches mainly develop on the scalp, knees, elbows and lower back, are often itchy and painful, and can crack and bleed.
• Guttate psoriasis, the second-most common type of psoriasis, is a form of psoriasis that appears as small, dot-like lesions. It often starts in childhood or young adulthood, and can be triggered by a strep infection.
• Inverse psoriasis shows up as very red lesions in body folds, such as behind the knee, under the arm, under the breast, or in the groin. It may appear smooth and shiny. Many people with inverse psoriasis tend to have another type of psoriasis elsewhere on the body at the same time
• Pustular psoriasis is characterized by white pustules (blisters of noninfectious pus) surrounded by red skin. Pustular psoriasis can occur anywhere on the body, but occurs most often on the hands or feet.
• Erythrodermic psoriasis, the rarest form of the disease, is particularly severe as it leads to widespread, fiery redness over most of the body. It can cause intense itching and pain, and can cause the skin to come off in sheets.

Some people who have psoriasis develop a form of arthritis called psoriatic arthritis. Most cases of psoriatic arthritis are diagnosed after the diagnosis of psoriasis, but the joint problems can sometimes begin before skin lesions appear. Common symptoms of psoriatic arthritis are swollen fingers and toes, foot pain, and lower back pain.

The main goal of treatment is to stop the skin cells from growing so quickly. Treatment for psoriasis and psoriatic arthritis can be provided in the form of systemics, also known as biologics. Biologics are different from traditional systemic drugs because they target specific parts of the immune system. The biologics used to treat psoriatic disease block the action of immune cells and proteins that cause psoriasis and psoriatic arthritis.