dry scalp

My 1.5 y.o has a pretty dry scalp. On top of that he has exzema and just really sensitive skin. He had a bad case of cradle cap as a newborn but now it's hard to get past the dry skin. I put lotion on his head a lightly brush it and it works good... until it comes back. His hair seems more straw like (not too bad though) and thiner in that area. anyone else have this problem with their LO? if so what helps keep it away?