The little boy I take care of is one. He scratches his face till it bleeds, pulls his hair, and screams. Why?

he cannot be soothed when he is like this. He continues to create this gargle - growling type cry, has little cuts all over his face from where he has clawed himself. I asked the parents, they just said he has a bit of a temper & gets fussy. I have never experienced 'fussy' in this manner.