What is alopecia areata? Alopecia areata is a disease that causes hair loss. In alopecia areata, the immune system attacks the structures in skin that form hair (hair follicles). Alopecia areata usually affects the head and face, though hair can be lost from any part of the body. Hair typically falls out in small, round patches about the size of a quarter. In some cases, hair loss is more extensive.
What is osteogenesis imperfecta? Osteogenesis imperfecta (OI) is a disease that causes your bones to break (fracture) easily. OI is also called brittle bone disease. Your symptoms may be mild or severe, depending on the type of OI you have.
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 spinal stenosis? Spinal stenosis happens when the spaces in the spine narrow and create pressure on the spinal cord and nerve roots. The spinal cord is a bundle of nerves that comes out of the base of the brain and runs down the center of the spine. The nerve roots branch out from the cord. In spinal stenosis, the narrowing usually occurs over time.
What is pemphigus? Pemphigus is a rare disease that causes blistering on many parts of the body, including the skin and the inside of the mouth, nose, throat, eyes, and genitals. In pemphigus, the immune system mistakenly attacks cells in the top layer of the skin.
What is gout? Gout is a type of arthritis that causes pain and swelling in your joints, usually as flares that last for a week or two, and then go away. Gout flares often begin in your big toe or a lower limb. Gout happens when high levels of a substance called serum urate build up in your body. When this happens, needle-shaped crystals form in and around the joint. This leads to inflammation and arthritis of the joint. However, many people with high levels of serum urate will not develop gout. With early diagnosis, treatment, and lifestyle changes, gout