A.It would be very difficult for me to definitively diagnose the problem via this column, but the most common thing I have witnessed that causes signs/symptoms such as these is, believe it or not, good old fleas. The distribution pattern for the medical condition known as flea allergy dermatitis is invariably around the base of the tail and down the back surfaces of the rear legs. Bites in these areas can cause the symptoms you are describing. Remember too, that fleas live most of their time off the animal so you don’t necessarily have to see them. By definition, this is an allergy to flea saliva. High carbohydrate diets are not only “unnatural”, but can precipitate or worsen allergy conditions. This could be why the dietary change made some difference. If fleas are truly your dog’s problem, there are many products on the market to address the allergy and help naturally repel the fleas.