What Causes Swelling And Redness In The Hand?

MY husband has swelling and redness on the top of his hand, very sore, bothers him to use that hand. Have him icing it at this time. Pain seems to radiate from the the bump near the wrist directly in line with the pointing finger. Doesn t remember hitting it, no bite marks. He thinks it s an arthritis flare, but he has never been diagnosed with arthritis other than an osteoarthritic hip that was replaced this May. Earlier this summer he reacted much the same way on both hands (very red and swollen - looked blistered but did not peel), but we thought it was a reaction to a spray Banana Boat Sun Screen that he had never used before. It went away after a few days. Today he had on sun screen again (Banana Boat regular 50 that he always uses) but had leather gloves on. Could it be the sunscreen? He used it on his arms & face, no problems there. Is there reason for concern or a trip to the ER?