Many times, no fleas will be on the pet when examined, however, the intense biting and itching occurring near the base of the dogs tail is a giveaway. Allergic reactions to inhaled substances begin to appear at 6-24 months of age. Usually, the first experience with an inhalant allergens coincides with plant pollination. In time, however, seasonal patterns may be lost as the patient becomes sensitive to dust and other materials. Ragweed and grasses are among the most potent pollens causing allergies.
Food allergy is the least common but most overlooked cause of allergies.
Food allergic dogs develop this sensitivity against a particular item in their diet. The most common allergens in food are corn, meat, milk, whey, gluten, and soy. Dogs suspected of being food allergic need to be placed on a hypoallergenic diet for a minimum of 6-10 weeks and the response observed. Hypoallergenic diets have novel food groups such as lamb and rice as the main ingredients and lack any suspected allergens. Food allergies can only be diagnosed by a food trial.