What is ichthyosis? Ichthyosis is a group of skin disorders. It leads to dry, itchy skin that appears scaly, rough, and red. The symptoms can range from mild to severe. Ichthyosis can affect only the skin, but sometimes the disease can affect internal organs, too.

What is reactive arthritis? Reactive arthritis happens when an infection causes joint pain and swelling. A bacterial infection in the digestive or urinary tract or the genitals usually triggers the condition, but arthritis symptoms typically do not start until a few weeks after you have recovered from the infection. The most common features of reactive arthritis are inflammation of the joints (especially the knees and ankles), eyes, and urinary tract, but not everyone gets all three, or they might not happen at the same time.

What is atopic dermatitis? Atopic dermatitis, often called eczema, is a chronic (long-lasting) disease that causes the skin to become inflamed and irritated, making it extremely itchy. Scratching leads to: Redness. Swelling. Cracking. “Weeping” clear fluid. Crusting. Scaling. In most cases, there are times when the disease is worse, called flares, followed by times when the skin improves or clears up entirely, called remissions. Atopic dermatitis is a common condition, and anyone can get the disease. However, it usually begins in childhood. Atopic dermatitis cannot be spread from person to person. No one knows what causes atopic dermatitis. Depending on

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