A swollen and very painful bunion is commonly caused by the following: First, local trauma, such as a joint sprain or fracture dislocation, can cause severe local swelling, severe painful symptoms, and can be accompanied by limited movement of the bunion joint. Patients usually have a clear history of trauma, and x-rays can be taken to detect the presence of fractures and dislocations. Second, in gouty arthritis, serum uric acid metabolism is impaired and gout crystals are deposited in the bunion joint and subcutaneous tissue. Serum uric acid may be significantly higher when checked. Swelling and severe pain in the foot bunion should be diagnosed and treated promptly to restore normal local function as soon as possible.