Can chronic stomach problems be due to allergies?

Dogs that have sensitive stomachs can sometimes benefit from diets that have a low allergen content (for example diets that contain hydrolised proteins). In these cases a food allergy is suspected. There is an increased likelihood of food allergy if the dog in addition to diarrhoea also suffers from pruritus (an itch seen as excessive licking, chewing or scratching) and/or skin rashes.