Allergies are among the top reasons for canine and feline veterinary visits. Heredity can play a role in a pet’s predisposition to developing allergies, with certain breeds being statistically more likely to develop allergies, but all breeds of cats and dogs can develop allergies after two or more exposures to a given allergen.
The first exposure causes an animal’s immune system to produce antibodies in response to the allergen while subsequent exposures trigger the allergen-antibody reaction, which releases histamine, large quantities of white blood cells, and hormones into the bloodstream. Histamine is the chemical that is responsible for the symptoms associated with an allergic reaction.
While symptoms of an allergic reaction vary, itchy, swollen skin is the primary symptom of allergies in pets. “If left untreated, dogs and cats with seasonal allergies will scratch or lick themselves constantly,” says Dr. Link Welborn, AAHA past president. “In an attempt to relieve themselves, dogs and cats often create sores that become secondary infections.” Symptoms of an allergic reaction also include difficulty breathing and disruption of the digestive system, which can lead to diarrhea or vomiting.
While allergies are incurable, lifelong conditions, you can do much to decrease your pet’s discomfort. The first order of business is to isolate the allergen(s) causing the allergic reaction so you can ensure that your pet’s environment is free of the irritant(s).
Allergens responsible for triggering allergies in pets often fall into one of four main categories, namely flea, environmental, contact, and food allergens, with flea and environmental allergies being more common in pets than contact or food allergies. If your pet’s allergies do not appear to result from one of these four main categories of allergens, consult your veterinarian. She may decide to run one of several possible tests to learn more about your pet’s allergies.
Flea allergies are possibly the most common of all, though it isn’t the fleas themselves that trigger an allergic reaction in susceptible pets. Instead, pets with this allergy are allergic to proteins secreted by fleas in their saliva.
Also note that pets with this allergy do not have to suffer a severe bout of fleas to trigger an allergic reaction. A single bite from an isolated flea can cause itchy skin for up to 5 days. This makes frequent flea baths and prescription flea applications and pills a good idea for pets diagnosed with this allergy.
Consult your veterinarian before choosing a flea preventive for your pet. Be sure to also treat your pet’s environment to be sure that all bedding and carpeting is free of fleas.
Environmental—or inhalant—allergens include the pollens and molds often found in ambient outdoor air during spring or fall. Allergies to dust mites, mildew, and molds found indoors also fall into this category.
Pets with allergies to environmental allergens often scratch themselves vehemently, with itchy areas frequently concentrated to their ears, feet, groin, and underarms, though the itching can spread over their entire body. Even more so than cats, dogs with this allergy are prone to developing hairless hot spots as a result of their constant chewing and scratching.
High-pollen times of the year often cause pets with this allergy to suffer the most, underscoring the commonly seasonal aspect of this allergy. For pets who seem to suffer seasonally, limiting their time outdoors during allergy seasons may naturally alleviate some of their symptoms.
But if your pet suffers from indoor, or non-seasonal, environmental allergies, there is little you can do to keep your pet away from the allergens that affect him. For some pets with indoor allergies, air filters help.
Contact allergies are the least common type of allergy to affect pets and result from an animal’s skin coming into contact with a material that he is allergic to. The skin at the point of contact will become irritated, which often causes it to itch, thicken, or discolor. The animal’s scratching can also dislodge or break hair in the affected area, causing thin patches.
While uncommon, these allergens are typically the easiest to isolate. Try removing materials that your pet’s skin comes into contact with, one at a time, from his environment until his symptoms resolve.
Food allergens, on the other hand, can be challenging to isolate. Most pets are not born with dietary allergies, but instead their immune systems develop an allergy to an element of their diet over time. Often, one of the animal proteins triggers the reaction.
Over-the-counter diets do not help to isolate food allergens, so consult your veterinarian to obtain novel protein diets. And remember that the allergic effects of food allergens can stay in a pet’s system for 8 to 12 weeks.
You may have to try several diets before you find one that doesn’t trigger an allergic reaction in your pet. While you are trying these test diets, you will need to ensure that your pet does not consume any treats, vitamins, or leftovers. She will need to eat only the test diet for the entire 8 to 12 week trial period in order to determine if a particular diet triggers an allergic reaction.
Pet allergies are difficult to treat because pet owners often struggle to determine the allergen behind their pet’s reaction or they are unable to fully remove a discovered allergen from their pet’s environment. This is where veterinarians can help.
With the assistance of your veterinarian, a treatment plan can be developed to mitigate a pet’s allergies. From testing to immunotherapy, antihistamines, and even steroids, which work to suppress the immune system, thereby making the allergic reaction less severe, veterinarians can help pet owners relieve their pet’s allergies or allergy symptoms.
Isolating and treating pet allergies can be a complex undertaking. With many potential allergens and ambiguous symptoms, simply determining that your pet is suffering from allergies can be a challenge in and of itself. Take special note of your pet’s symptoms and any possible irritants that exist in his environment, and consult your veterinarian promptly, with as much information as possible.
Based in Denver, Colo., where she lives with her Rhodesian ridgeback mix, Jennifer Ryan writes for the American Animal Hospital Association.
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