What Causes Swelling All Over The Body And Weight Gain?

Thank you. Our son who is 31 just contacted us and said his body is swelling - hands, feet, face, whole body. He said it doesn't itch, but he has gained 25 pounds since yesterday. We advised him to go to the emergency room. He has been gaining weight, about 30 pounds, over the last months, but gradually. He is 6ft4inchs tall.