Sudden swelling and thickening of the digit is considered to be related to trauma, rheumatoid arthritis, osteoarthritis and other factors. 1. Trauma: traumatic injury resulting in finger fracture or soft tissue contusion will appear finger swelling pain and thickening of the manifestations, generally have a history of sprains and other traumatic injuries. 2. Rheumatoid arthritis: the proximal interphalangeal joints, metacarpophalangeal joints and other small joints of the fingers first, manifested as morning stiffness, swelling, pain, and severe deformity of the joints. 3. Osteoarthritis: it occurs in weight-bearing joints and distal interphalangeal joints, proximal interphalangeal joints, etc. It mainly manifests as joint pain, stiffness, swelling, and impaired movement. Sudden swelling and thickening of the finger may also have other causes, such as swelling and pain continue to be unrelieved, it is recommended to consult a doctor in a timely manner, improve the examination to determine the cause of the disease, and then give targeted treatment or treatment.