Swelling and thickening of the thumb may be due to traumatic factors, arthritis, tumor and gout. 1. Traumatic factors: thumb phalangeal fracture, joint dislocation may cause swelling of the finger, there will be transient thickening, resulting in limited activities, there is obvious pain phenomenon, generally need to choose early fixation and reset, cold compress treatment. 2. Joint inflammation: including rheumatoid arthritis, degenerative osteoarthritis, can lead to finger swelling, thickening, and even finger skewing, after taking X-ray film will find that the joint force line changes. 3. Tumor: if there is a tumor in the thumb bone and soft tissue, it will also lead to swelling and thickening of the thumb, and then ultrasound and nuclear magnetic examination should be done. 4. Gout: If gout stone exists in the thumb, there will be swelling and thickening of the thumb, and usually there will be severe pain. There are many reasons for the swelling and coarsening of the thumb, so it is recommended to go to the regular hospital in time for examination to determine the cause of the condition before it can be effectively controlled.