4 year old with possible anxiety?

Is nail biting a sign of anxiety? He has Eczema on his legs and all night he’s been picking at the bumps until they bleed (as he does all the time) I finally was able to get him to stop and he started biting what little nails he has and pulling off the skin around them. This is a pic of his hands every day. He literally always bites them and picks at his hands until they bleed