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 giant cell arteritis? Giant cell arteritis causes the arteries of the scalp and neck to become red, hot, swollen, or painful. The arteries most affected are those in the temples on either side of the head. These arteries narrow, so not enough blood can pass through. It is important that you get treatment right away. Otherwise, the arteries could be permanently damaged. There is also a risk of blindness or stroke. If you have giant cell arteritis, your doctor should also look for signs of another disorder, polymyalgia rheumatica. These conditions often occur together.
What is ankylosing spondylitis? Ankylosing spondylitis is a type of arthritis that causes inflammation in certain parts of the spine. Over time, this inflammation in the joints and tissues of the spine can cause stiffness. In severe cases, this may cause the bones in the spine to grow together, which can lead to a rigid spine that is difficult to bend. Many people with ankylosing spondylitis have mild episodes of back pain and stiffness that come and go. But others have severe, ongoing back pain and stiffness. Other symptoms also may develop if other areas of the body are affected