Ask the Vet! Helpful articles from the Precise® Vet, Dr. Lisa Drapela

What is an allergy?

In the body, antibodies are made by the immune system to substances that are recognized as foreign.   Each one is specific to the foreign invader.   IgE is the type of antibody involved in allergic dermatitis.   These antibodies cover the surface of mast cells found in the skin where they wait for contact with the specific invader.   When contact is made, the mast cells release their chemicals in an effort to destroy the invader. In an allergic animal, the whole immune system is oversensitive to invaders and the release of mast cell chemicals occurs inappropriately and in an extreme way. There are several types of allergies.   The three most common are flea allergy, inhalant allergy, and food allergy.   If the animal suffers from only one of these types or a combination, the signs are generally the same.   Dermatologic symptoms are scratching, biting, licking, chewing at feet, and reddened skin.   The dermatologic symptoms are the most common especially for flea and inhalant allergies.   Animals with food allergies more commonly show dermatologic symptoms but can also have vomiting and diarrhea. Flea allergies are very common in some areas more than others.   If you have a pet that is allergic to flea bites, it only takes one flea to send the pet into a scratching fury.   The main area where fleas are seen are around the base of the tail, lower back, and inside the hind legs.   The first line of defense in treating a pet with flea allergy is controlling the fleas on the pet and in the environment.   Flea treatments do not just consist of shampoos and collars any more.   Veterinarians are usually a good source for a complete armory of flea control products for the pet and the environment.   Many animals with other types of allergies can be made much more comfortable with minimal treatment once a flea allergy is addressed and under control. Atopy or inhalant allergy is the most common cause of allergies in dogs and it can be seen in cats as well.   The causes of atopy are as numerous as those for people.  Potential allergens include dust mites; molds; and grass, tree, and flower pollens. Atopy may appear as a seasonal problem initially and progress to a year-round problem as the pet ages.   Atopic dermatitis often appears in the first two years of age. Atopy may be suspected after taking a complete history and making a thorough examination of the pet, but diagnosis can be confirmed by skin testing.   Skin testing has been helpful because it helps veterinary dermatologists identify specific allergens to which the pet is allergic.   Avoidance of the allergens when possible is the best way to prevent allergies, but this is not always feasible.   Topical therapies such as shampoos, rinses, and topical anti-itch solutions offer immediate but short-term relief. Avoidance of the allergen is the ultimate treatment for the allergic pet, but it is not always very practical.   If the animal is allergic to dust mites, regular cleaning of bedding and vacuuming should be helpful.   Pets that are allergic to pollen can be rinsed down or wiped down with damp towels after they have been out during high pollen times.   In certain areas, molds may be difficult to avoid by some pets because the molds are ubiquitous.   In other areas, molds can be avoided by keeping pets out of damp rooms and using dehumidifiers during damp times of the year. Administration of omega-3 fatty acids orally has been helpful in treating the symptoms of allergies.   Basically, they work by helping to reduce the amount and effects of the mast cells and the chemicals they release when confronted by foreign invaders and allergens.   Fatty acid therapy does not work for all pets, but some animals will show a remarkable improvement. One major drawback of fatty acid therapy is that it does take several weeks before results can be seen.   Therefore, an owner must usually do some other type of treatment in combination with the fatty acid supplementation. Administration of antihistamines can be particularly helpful for pets that have seasonal problems or in combination with other treatments.   Use of antihistamines may be more beneficial for cats than for dogs but this should remain an option.   Because different animals respond differently to various types of antihistamines, several types can be tried before the correct one is found.   As in people, antihistamines have similar side effects on pets such as sedation, dry mouth, hyperactivity, and constipation. Immunotherapy, or hypo-sensitization, is another treatment option for pets, especially dogs, with good results.   It does require the animal to undergo intradermal skin testing to identify the exact antigens to which the pet is allergic.   A commercially prepared injection containing the exact antigens is then injected into the allergic pet in a series over the course of weeks to months.   Treatment can be time consuming and requires a dedicated owner and veterinarian, but it has been shown to have good results and should be a serious consideration if the allergic pet has not responded to any other conventional treatments. Steroids are an extremely useful tool when dealing with atopy.   They do have many unpleasant short- and long-term side effects but like many other drugs, they can be very beneficial when used correctly and at the lowest effective dose.   Steroids can be abused because they are so good at controlling inflammation and making the pet feel better quickly.   Many people are lead to believe they are a cure, instead of a short-term treatment option while other long-term treatments are being sought. Allergy to a food ingredient is another type of allergy, and food allergies account for about 10 percent of allergy problems in dogs.   Food allergies do not consistently respond as well as the other allergy types to corticosteroids.   The best way to diagnose this type of allergy is to place the pet on an elimination diet.   This diet consists of a minimum number of ingredients that are completely new to the pet.   The food should be comprised of ingredients the pet has never had before, and it may be as simple as a lamb and rice diet.   However, it may need to be something more novel such as fish and potato.   It is very important that this elimination diet be fed for eight to twelve weeks with no additional treats or supplements that may interfere with the trial.   The supplements and treats can contain hidden protein sources, such as flavorings, that may add potential allergens. If the pet shows much improvement after the twelve-week period, owners can begin adding back a former ingredient, roughly one each week, and watch for allergy symptoms to return.   If symptoms return after the addition of an ingredient, it can be concluded that ingredient is the cause of food allergy for that particular pet.   The best way to reduce allergy symptoms when food allergies are involved is to avoid the offending ingredients completely.   More commercial diets are being made that contain the novel ingredients and limited ingredients so that owners with food allergy pets have more options. If you think your pet suffers from allergies, please see your local veterinarian.   If referral is needed to a veterinary dermatologist, your veterinarian can do this to ensure that your pet receives relief from the “itches.”

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