Why would the back of my left hand just above the knuckles swell

Hello. Thank you for posting today.

Numerous conditions can cause swelling of the hands, including injury, arthritis or carpal tunnel. Hand swelling is also common during exercise, resulting from the way the body and blood vessels respond to the demands for more energy from the muscles. People who experience chronic hand swelling should consult a doctor for advice. In some cases, an underlying medical condition may be the cause of hands swelling.

Helena