Allergies are common in dogs and they crop up when your dogs immune system reacts to an otherwise harmless substance in its environment the digestive tract and skin are two of your pets most sensitive organs and they come into contact with many different substances your dog can develop allergies or intolerances to foodstuffs of vegetable or animal origin typical symptoms are itching and inflammation of the skin as well as sickness and diarrhoea royal canin hypoallergenic moderate calorie