Anyone got any ideas about why my dog is scratching? No sign of fleas, no sign of mites, coat and skin in v good condition, has food with no additives. He was scratching about 2 months ago then it all stopped and hes started again now. Weather is not particularly hot, he has got a thick coat. Cannot see anything on him at all. We are not using anything new at home in the way of soap powder, sprays etc. Have tried giving him piriton but not helping.