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 cicatricial alopecia? Cicatricial alopecia is a group of conditions that destroy hair follicles. Hair follicles are the part of the skin where the hair grows. The follicles are replaced with scar tissue. This means the hair will fall out and not grow back.

What is pachyonychia congenita? Pachyonychia congenita is a very rare disorder. It causes thick nails and painful calluses on the bottoms of the feet. In some cases, blisters also form on the palms of the hands.

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 osteoporosis? Osteoporosis is a disease that causes bones to become weak and brittle. This increases your risk of broken bones (fractures). Osteoporosis is a “silent” disease because you may not have symptoms. You may not even know you have the disease until you break a bone. Breaks can occur in any bone but happen most often in: Hip bones. Vertebrae in the spine. Wrist. You can take steps to help prevent osteoporosis and broken bones by: Doing weight-bearing exercises, such as walking or dancing, and lifting weights. Not drinking too much alcohol. Quitting smoking, or not starting if