Why does my 2 year old stink?

My son is 2 1/2 and just smells. Not like you can smell him across the room or anything, but if you hug him, you definitely smell him. He sweats a LOT (as does my husband, but hubby doesn't reek!) When I put him to bed and check on him, his hair is always wet, like he just took a bath. He sweats in his sleep and during his hour long naps. Any ideas?? Should I just take him to the doctor??