Swelling of the thumb is considered to be related to gout, rheumatoid arthritis, tenosynovitis, bone fracture and so on. 1. Gout: mainly redness, swelling and pain in the joints, the pain is more intense, and the test of uric acid can make a clear diagnosis. 2. Rheumatoid arthritis: Symmetrical swelling of the joints, accompanied by morning stiffness, limited joint movement, rheumatism test can be a clear diagnosis. 3. Tenosynovitis: stenosing tenosynovitis of the thumb flexor muscle can present with swelling of the thumb, elasticity and pain in flexion and extension, which can be treated by surgical release of the tendon sheath. 4. Fracture: If the thumb swelling is obvious after trauma, consider the possibility of fracture, and need to take radiographs to further clarify the diagnosis. When thumb swelling occurs, it is recommended to go to the hospital for further examination to clarify the cause and treatment.