Additionally, skin infections are often symptoms of an underlying disease, and in dogs with chronic diarrhea, food allergy is highly suspect, so you may want to talk to your veterinarian about starting a prescription hypoallergenic diet trial (unfortunaely, there are no accurate
skin or blood tests
for food allergy, the test and
treatment are the hypoallergenic diet trial for 6-8 weeks with no other foods or treats).