I know 3 dogs like yours that have lost there fur and a little scabby, The vet's said its an allergy with it beeing spring everything shooting and the new grass growth, try piriton tablets, ( Antihistamine ) ring the vet to find out what dose to give depending on size of dog, its perfectly harmless and will help with the itching/scratching, you can also rub germaline/savlon on the scabs but make sure the dog does not like the scab as tigger could end up with a skin infection and may need antibiotics.....Hope this helps