The common causes of swollen and unbendable fingers include trauma, onychomycosis, rheumatoid arthritis, stenosing tenosynovitis, etc. The treatments are different according to the causes of the disease, and the treatments include proper rest, medication, and surgery. 1. Trauma: If the finger is swollen and unbendable after trauma, it may be soft tissue injury or metacarpal bone fracture, which needs perfect X-ray examination. Soft tissue injury can be properly rested, and non-steroidal anti-inflammatory drugs such as Celecoxib can be taken orally to relieve pain, while bone fracture needs external fixation by splint or internal fixation by Kirschner’s pin. 2. Nail groin infection: If the finger is red, swollen, not able to bend, fever or even pus, it is mostly nail groin infection, which is caused by Staphylococcus aureus infection after the skin of the finger is broken. Need to carry out bacterial culture, according to the results of anti-infection treatment, such as cephalosporin, pus need to be incised and drained. 3. Rheumatoid arthritis: if both hands at the same time the symptoms of swelling, can not bend may be rheumatoid arthritis. Diclofenac sodium and other non-steroidal anti-inflammatory drugs can be used to relieve pain, anti-rheumatic drugs, such as methotrexate to delay the disease. 4. Stenosing tenosynovitis: If there is mild swelling, pain and popping in the fingers, it may be stenosing tenosynovitis. You can use trimethoprim and lidocaine for closed treatment, or take diclofenac sodium extended-release tablets orally to reduce inflammation and relieve pain. There are more causes of finger swelling and inability to bend, if the symptoms continue to be unrelieved, it is recommended to consult a doctor in a timely manner to clarify the cause of the disease and carry out targeted treatment.