Localized (Contact) Allergens: These are allergens that come into direct contact with the dog’s skin and cause an allergic reaction. The most common allergens are grass and pollen. Localized allergens usually cause dermatitis on the dog’s feet or belly. You will see your dog chewing or licking their feet. This aggravates and inflames the skin even more, which in turn causes the dog to lick and chew. It can become a vicious cycle. The best way to prevent this is to prevent the contact. There are several ways to accomplish this: make sure the hair your dog’s feet is clipped short. The hair can trap the allergen against the skin. Rinse your dog’s feet off when he comes in from being in the grass; or alternatively, have your dog wear booties on his feet when he is outside. If your dog is severely sensitive to these allergens, then he may require medication, such as anti-histamine or steroid therapy.
Food Allergens: The most common ingredients in food that dogs are sensitive to are: Beef, Chicken, Pork, Wheat, Corn, and Soy. However, they can be sensitive to other ingredients as well. One of the ways to determine if your dog may have a food allergy is to note whether or not the skin lesions are present all year round or seasonally. Due to the fact that your dog is exposed to his food all year, these allergies never clear up. Also, food allergy dermatitis will often cause chronic ear infections. This is due to the fact that the skin inside the ear is the most sensitive skin on the dog’s body. Other allergens can cause ear infections, so an ear infection doesn’t guarantee that your dog has a food sensitivity, but you would definitely need to rule it out as a possibility.
Diagnosis of a food allergy is done by starting a feeding trial. A feeding trial involves placing your dog on a very restricted diet consisting of ingredients not found in your dog’s normal diet. There are commercially available foods for this purpose or a home-made meal can also be used. The feeding trial needs to be conducted for several months to give the dog’s skin time to heal and all the allergens to be eliminated from the dog’s system. It is also very important to cut out treats, table scraps, etc during the feeding trial to eliminate them as the possible source of the allergens. Once a diagnosis of food sensitivity has been confirmed, then you can try reintroducing your dog to different treats/dog foods to determine which specific ingredients your dog is sensitive to.
Generalized Allergens: There are a variety of allergens that can cause generalized reactions in dogs. These include: Dust, pollen, dander, fleas, molds, cigarette smoke, cleaning solutions, and shampoos. Dogs with severe generalized reactions are often sensitive to more than one allergen. These can be difficult to completely control. Diagnosis is usually done by a dermatologist who runs a skin test to determine sensitivities to common allergens. Finding out what allergens your dog is sensitive to is key to being able to control the symptoms. The more you can limit your dog’s exposure to the allergens, the more successful you will be at controlling your dog’s reactions.
Treatment of generalized sensitivity reactions usually involves multiple steps: First, limiting your dog’s exposure to the allergen. Second, using a topical treatment of the inflamed skin with medicated shampoos, steroid sprays, etc. Third, giving oral medications such as fatty acid supplements, anti-histamines, and/or steroids. Allergy injections may also be needed to help de-sensitize your dog to the offending allergen.