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 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 bursitis? Bursitis is a common condition that causes swelling and pain around muscles and bones. Bursitis is the swelling of the bursa, a small, fluid-filled sac that acts as a cushion between a bone and other moving parts, such as muscles, tendons, or skin.

What is reactive arthritis? Reactive arthritis is pain or swelling in a joint that is caused by an infection in your body. You may also have red, swollen eyes and a swollen urinary tract. These symptoms may occur alone, together, or not at all. Most people with reactive arthritis recover fully from the first flare of symptoms and can return to regular activities 2 to 6 months later. Some people will have long-term, mild arthritis. A few patients will have long-term, severe arthritis that is difficult to control with treatment and may cause joint damage.

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.