Rheumatoid arthritis almost always affects the hands, and swelling is one of the main symptoms associated with the disease, according to WebMD. Rheumatoid arthritis causes fluid to enter the joints, which causes swelling and stiffness.
Osteoarthritis and rheumatoid arthritis cause many similar symptoms, but rheumatoid arthritis usually causes more long-term swelling and redness than osteoarthritis, notes Cleveland Clinic. Normally, stiffness accompanies swelling of the hands. In the early stages of rheumatoid arthritis, individuals may feel weak or tired or have a loss of appetite. As the disease progresses, loss of motion in the hands may occur, along with pain and joints that are tender to the touch.