What is psoriatic arthritis? Psoriatic arthritis can occur in people who have psoriasis (scaly red and white skin patches). It affects the joints and areas where tissues attach to bone. The joints most often affected are: The outer joints of the fingers or toes. Wrists. Knees. Ankles. Lower back.

What is osteonecrosis? Osteonecrosis is a bone disease. It results from the loss of blood supply to the bone. Without blood, the bone tissue dies. This causes the bone to collapse. It may also cause the joints that surround the bone to collapse. If you have osteonecrosis, you may have pain or be limited in your physical activity. Osteonecrosis can develop in any bone, most often in the: Thigh bone (femur). Upper arm bone (humerus). Knees. Shoulders. Ankles. It is also called: Avascular necrosis. Aseptic necrosis. Ischemic necrosis.

What is epidermolysis bullosa? Epidermolysis bullosa is a group of rare diseases that cause fragile skin that leads to blisters and tearing. Tears, sores, and blisters in the skin happen when something rubs or bumps the skin. They can appear anywhere on the body. In severe cases, blisters may also develop inside the body. The symptoms of the disease usually begin at birth or during infancy and range from mild to severe.

What is alopecia areata? Alopecia areata is a disease that attacks your hair follicles (the part of your skin that makes hair). In most cases, hair falls out in small, round patches about the size of a quarter. This causes only a few bare patches. Some people may lose more hair. In only a few people, the disease causes total loss of hair on the head or loss of all body hair. Your hair may grow back, even if you lose all of it. But it may fall out again. No one can tell you when it might fall out

What is Behçet’s disease? Behçet’s disease can affect different parts of your body. If you have the disease, you probably have sores in the mouth or on the genitals (sex organs). More serious symptoms can include swelling, heat, redness, and pain in the eyes and other parts of the body. The disease is named after the doctor who first described it, Dr. Hulusi Behçet.