A. The most typical place for flea related chewing is the lower back area but I'm sure it's been ruled out. Of the flea treatment has not been change I would advice to change it just in case, even if you can't find any fleas as some dogs suffer from flea allergy and one flea would be enough. Other than that the next highest possibility would be allergy. This could be from food or environmental and this is usually more complicated to solve. Ask your vet about allergy tests option.
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