What is psoriasis? Psoriasis is a chronic (long-lasting) disease in which the immune system works too much, causing patches of skin to become scaly and inflamed. Most often, psoriasis affects the: Scalp. Elbows. Knees. The symptoms of psoriasis can sometimes go through cycles, flaring for a few weeks or months followed by times when they subside (or go into remission). If you have psoriasis, you may have a higher risk of getting other serious conditions, including: Psoriatic arthritis. Heart attack or stroke. Mental health problems, such as low self-esteem, anxiety, and depression.

What is osteonecrosis? Your bones are made up of living cells that need a blood supply to stay healthy. In osteonecrosis, blood flow to part of a bone is reduced. This causes death of bone tissue, and the bone can eventually break down and the joint will collapse. Osteonecrosis can happen to any bone, but most often it develops in the ends of long bones, such as the: Thigh bone. Upper arm bone. Less often, the bones of the elbows, ankles, feet, wrists, and hands are affected. When the disease involves part of a bone in a joint, it can

What is Raynaud’s phenomenon? Raynaud’s phenomenon is a condition that causes the blood vessels in the hands and feet to narrow, decreasing blood flow. When this happens, parts of the body—usually the fingers and toes—become cold and numb, and change color (usually, to white or blue). An attack usually happens from exposure to cold or stress.

What is pachyonychia congenita? Pachyonychia congenita (PC) is a very rare genetic disorder that affects the skin and nails. Most people have thickened nails and calluses on the bottom of the feet. Painful calluses on the soles can make walking difficult. Because of the pain, some people rely on a cane, crutches, or a wheelchair to help with walking.