Ask the Veterinarian: Beastly Allergies

By Dr. Hagerty and Avery

Blossom petals float down like a soft shower of pastel pink raindrops. Bright yellow pollen clings to the bees’ legs and coats everything with the dusting of propagation. Grass takes control over the brown mud of winter and sunshine forces the windows of houses open wide. It’s spring. For some this means the watery eyes, sneezing noses and itchy skin of allergy season has begun. 

What is an Allergy?

Many of us have them, but what actually is an allergy? An allergy is a state of “over-reactivity” or hypersensitivity of the immune system to a specific substance, known as the allergen. When the body becomes exposed to the allergen for the first time or more commonly over a period of time, the immune system becomes sensitized, triggering a complex cascade of interactions between antigens, antibodies and a specific cell type known as mast cells. These dealings wreak havoc on the mast cells and release powerful biochemical substances into the surrounding tissues and throughout the body.

What are the Signs?

Itching. From licking to chewing of the feet, over grooming, to intense scratching and even self-harm, your pet’s focus is overwhelmed by the need to itch. The area may be small or may involve the whole body. The skin is often pink or red, and may feel greasy or give off an unpleasant or different odour. The inflamed and damaged skin becomes susceptible to bacterial infections, and overgrowth of once normal pathogens. The condition becomes increasingly uncomfortable, itchy and very painful for your pet. In some cases, coughing, sneezing, runny discharge from the eyes and nose may also be seen. Allergic symptoms may also manifest as digestive systems concerns, including vomiting and diarrhea.

In general allergies can be broken up into the two most common presentations in dogs and cats; Environmental allergies, and food allergies. Flea or insect bite allergies are also common and may accompany the other allergy types.

Environmental Allergies

That sweet, warm, sun-cured smell of freshly cut hay is the most distinct smell of summer for me. Haying season was one of the best parts of summer for me growing up. However, for someone with allergies this week of grasses, dust, and summer air would be the death of them. Hay fever or other environmental allergies in our pets is known as atopy or atopic dermatitis and is most commonly manifested as itchy skin. Unfortunately, being an indoor only pet doesn’t prevent environmental allergies, as mold, mildew, house dust mites and other allergens often concentrate indoors. Symptoms of atopy may or may not be seasonal and often develop between the age of two and four years old.

Unfortunately atopic dermatitis is not a curable condition, but it can be a very manageable one. Cortisone-type medications and antihistamines, similar to those used in management of human allergies are tools used to deal with flair ups for our pets. However, long-term use of these medications can sometimes be harmful and can have unwanted side effects. Fortunately, new research has expanded our options. Some newer medications work with the immune system and the complex biological pathway of the “itch” cycle to modulate the immune response or even block the “itch” signal from reaching the brain. Omega 3 and omega 6 fatty acids, flea control, proper coat care and environmental hygiene are other things you can discuss with your veterinarian to help provide relief for your itchy pet.

Food Allergies

We all understand food allergies, weather it is peanuts, strawberries or shellfish. For our dogs and cats, they also eat a variety of foods containing different forms of nutrients and additives. Proteins or carbohydrates may be combined or changed into substances, which the immune system deems an allergen. Proteins, such as chicken, lamb or soy are a few of the most common food allergies in dogs. Similar to environmental allergies, skin is the target organ that is impacted by food allergies, resulting in itching and inflammation. In some cases, gastrointestinal involvement may also occur (typically seen in 30% of the cases). A dog or cat of any age can develop food allergies, including young puppies and kittens or even older senior pets that have been on the same food for many years.

Fortunately, with a bit of detective work and some careful feeding strategies we can determine if your pet does have a food allergy. Diet trials or feeding trials are the first step to discuss with your veterinarian. A test diet is carefully selected. The first option is a novel protein diet, with a single protein source which you’re pet has never had before. Yes, it’s going to be something exotic like kangaroo or rabbit. This way his or her immune system isn’t armed and ready for it. This surprise attack stops the body from overreaching with troops ready, as it does with an established “allergen”. If foreign cuisine isn’t the option selected by your veterinarian, you’re pet will be placed on a hydrolysed protein diet. This means instead of a surprise attack, a “Trojan horse” method is used. Hydrolysed diets take proteins your pet has had before, but breaks them down into molecules too small to excite the immune system, foiling an attack. Both forms of diet trials need 4-6 weeks to work and require a bit of tough love. This means not being tempted to allow your pet “cheat days” or caving in to giving tablet scraps.

Don’t admit defeat

Not only dogs and cats can have allergies, they are also seen in many other species. Fiona is a very large, slightly rotund, but gentle soul. She is a horse, a Friesian Clydesdale cross to be exact. She has the build capable of pulling a cart, and the head carriage of a parade horse and looks slightly menacing when forming an all black silhouette towering over you at dusk. However, the smallest creature is her nemesis. She’s allergic to tiny flying gnats (nicknamed “no-see-ums” but officially called Culicoides). She’s allergic to the protein component of their saliva, which causes intense itching. This causes her to scratch. However, unlike a dog or a cat, her scratching has taken fence posts out and trampled trees down.

Without careful management and medication, this majestic horse is slain by a tiny fly. But don’t let allergies control you or your pet’s life, we have the tools to fight back!

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