The most common causes of swollen feet are gouty arthritis, rheumatoid arthritis and psoriatic arthritis, which are as follows: the first one is gouty arthritis: if the patient’s feet are swollen at night when he sleeps, especially after drinking alcohol and eating high-purine diets, such as seafood, animal offal and soy products, then swelling and pain on the surface of the feet will be gouty arthritis, and he or she can go to the hospital to check the uric acid and blood sedimentation and C-reactive protein, and the diagnosis will be clear. The second is rheumatoid arthritis: rheumatoid arthritis mainly affects the small joints of the feet, that is, the metatarsophalangeal joints and interphalangeal joints. If someone in the family suffers from rheumatoid arthritis, has a family history of rheumatoid arthritis, or the hands are swollen and painful at the same time, it is considered that rheumatoid arthritis may occur; the third one is psoriatic arthritis: psoriatic arthritis belongs to a kind of arthritis of the spine. Psoriatic arthritis: psoriatic arthritis is a kind of spinal arthritis, after the occurrence of the patient’s feet will be swollen, the toes are weenie toes, check whether there is sacroiliac joint destruction and whether HLA-B27 is positive, then the diagnosis can be clear.