Swelling and pain in the thumb may also be caused by overstrain of the thumb, or it may be caused by gout, or it may be caused by infection. 1. Overstrain: the thumb belongs to the most important finger in the hand function, there are many muscles, tendons, ligaments and other soft tissue structures around the thumb, the usual daily work life if the thumb is used for a long time, may cause the thumb and its surrounding soft tissue fatigue, aseptic inflammation, causing swelling and pain symptoms. 2. Gout: itself due to the body’s hyperuricemia gout, may also appear in the finger joints of the accumulation, resulting in urate crystals and the body’s immune system metamorphosis, caused by immune complexes deposition, may also appear in the thumb of the symptoms of swelling and pain, the serious patients may appear in the gouty stone performance. 3. Infection: various reasons cause the thumb area to appear pathogenic bacteria invasion, will cause local vascular inflammatory reaction, may also appear thumb swelling and pain symptoms, such as inguinitis, purulent dactylitis. The symptoms of swelling and pain in the thumb alone sometimes cannot accurately determine the cause, and it is also necessary to rule out the presence of bone tumors and fractures and other diseases. It needs to be combined with the characteristics of the medical history and other test results to make an accurate judgment, and it is recommended to clarify the cause of the disease under the guidance of a doctor.