Allergies are a very common cause of skin disease in dogs and cats. Most of the time, the allergies are due to environmental allergens such as various pollens, molds, and house dust mites. While many pets have food sensitivities, true food allergies are quite rare. Despite the fact that many food companies claim their foods are ?hypoallergenic? and won?t cause your pet to itch, this is rarely the case. Since I started in the veterinary proofession, I?ve seen less than a handful of pets with true food allergies. That?s not to say that pets might not itch less when switched to a better diet. I think a better more natural diet is important for all pets. I just doubt that a dietary problem is the cause of nost itchiness in pets. In fact, most pets with allergies to environmental allergens have normal skin (unless they have secondary infections or the allergies are a chronic problem that have never been treated.) Conversely, most pets with food allergies are not only VERY itchy, their skin is abnormal; usually they have severe ulcerations with bleeding and crusting. Blood allergy testing can be helpful in diagnosing environmental allergies in pets, although skin testing is considered the gold standard. However, blood testing is useless in diagnosing food allergies; many normal pets will show an ?allergic response? on blood testing to various foods such as wheat, corn, or other grains. Instead, a food trial in which a hypoalllergenic diet is fed exclusively for 8-12 weeks is the proper way to diagnose this problem.