Swelling of the index finger may be caused by the following aspects: 1. It may be a local inflammation of the joints of the fingers, usually sterile inflammation is more common, commonly gouty arthritis, rheumatism or rheumatoid arthritis. If the onset of the disease is preceded by alcohol consumption, eating animal offal, eating seafood, etc., it should be more likely to be gouty arthritis. If you want a clear diagnosis, you can go to the hospital to check the blood uric acid and rheumatism three, combined with clinical finger local joint redness, swelling, heat, pain, basically is able to confirm the diagnosis; 2, may be the finger of the infectious inflammation, the most common is the nail groove infection, resulting in the entire finger bacterial infection, you can see the nail groove where there is ooze or pus; 3, there are It may be a local allergic skin reaction, such as a mosquito bite or contact with allergic substances, which may lead to swelling, skin flushing and itching.