Arthritis affects the joints, causing pain, stiffness and swelling. The knuckles are commonly affected by arthritis and the inflammation may cause not only pain, but also visible swelling. Some forms of arthritis occur in conjunction with or as a result of other underlying disorders, while other forms are disorders in their own right. Treatments for arthritis depends on the type, so an accurate diagnosis is essential.
Osteoarthritis
Osteoarthritis, the most common form of arthritis, happens when the bone and cartilage of a joint break down. Old age may be a factor in the development of osteoarthritis. When osteoarthritis affects the hands, the knuckles are often one of the first areas to be affected. According to the Centers for Disease Control and Prevention, osteoarthritis affects 33.6 percent of people over the age of 65 and is more prevalent in women than in men.
Rheumatoid Arthritis
Rheumatoid arthritis occurs when the body;'s immune system malfunctions and attacks the joints. According to the National Institute of Arthritis and Musculoskeletal and Skin Diseases, rheumatoid arthritis affects about 1.3 milion people in the U.S. and is more common in older individuals and women. Rheumatoid arthritis typically strikes both sides of the body at once, affecting the knuckles of both hands instead of just one, for example. Rheumatoid arthritis in the knuckle frequently causes deformities that affect the entire finger.
Gout
Gout is a form of arthritis that is more prevalent in men, explains the CDC. In a case of gout, crystals of uric acid build up in the joints, causing pain and a decrease in the ability to use those joints. Gout often develops asymmetrically, affecting one knuckle joint but not the corresponding joint on the other side of the body. Gout can be acute, flaring up in painful short-term instances, or chronic.
Pseudogout
Pseudogout is similar to gout but involves the buildup of calcium pyrophosphate crystals, not uric acid, in the joints. The knuckles of either hand can be affected. Because the difference in crystals can't be determined without physical observation, a doctor has to pull fluid from the joint with a needle to view it under a microscope and accurately determine which type of arthritis it is.
Spondyloarthropathies
Spondyloarthropathies are arthritic diseases that cause joint inflammation alongside other symptoms, according to The Merck Manuals Online Medical Library. Some researchers believe that they are all one disease that manifests in different ways in different people, while others maintain that they are separate related disorders. Psoriatic arthritis is a spondyloarthropathy that develops in people who have psoriasis, a skin disease. Reactive arthritis, or Reiter syndrome, occurs in conjunction with an infection such as the sexually transmitted disease chlamydia or gastrointestinal infections.
