I have had him to the vets he looks much better but over the past few weeks he has started getting scabs on his back black ones started small but have become larger can u please help

Did you change his diet to grain free/wheat free food? I started my dogs on healthier foods and they have both improved health wise.

Yes he is on a strict diet and has piriton tablets every day but this scan started small and has grew bigger even though his skin and fur is looking loads better it is on one ov the patches on his back