Sudden swelling and pain in the foot may be related to foot trauma, acute attack of gout, foot fasciitis and other elements. 1. Foot trauma: when the foot suffers from external impact or sprain, it may lead to ankle soft tissue injury or even ankle fracture, which may cause sudden swelling and pain in the foot, accompanied by local skin bruising. 2. Acute attack of gout: gout is a kind of arthropathy caused by the deposition of monosodium urate in the body, when the patient’s body serum uric acid rises, resulting in acute attack of gout, it may cause sudden swelling and pain in the feet. 3. foot fasciitis: foot fasciitis is mainly manifested as foot pain, swelling, dyskinesia, numbness of the skin and other symptoms, cold or overload exercise and other factors can induce inflammation aggravation, there will be a sudden swelling and pain in the feet. In addition, lower extremity venous thrombosis, foot infection, foot allergies and other factors may also cause sudden swelling and pain in the foot, it is recommended that the patient consult a doctor in a timely manner for examination, to clarify the cause of the disease for targeted treatment.