Dogs can suffer from allergic reactions just like humans. Kylie Baracz discovers what type of allergies affect dogs and how you can help manage them in your pet.
Like humans, our pets can suffer from aggravating and itchy skin caused by allergies. According to Dr Rusty Muse, an expert clinical veterinary dermatologist specialising in aetiology and allergic skin disease management, the main allergies that affect dogs are split into three major types.
“The most common allergies diagnosed in dogs are environmental (pollen or indoor allergies such as dust mites), flea, food allergies or a combination of these,” says Dr Muse. “Allergies are manifested as chronic itching and scratching and are often accompanied by skin and ear infections.”
What causes itchy skin?
A combination of factors come together to cause a genetically predisposed individual to become sensitised to allergens.
According to Dr Muse, dogs that are allergic are born with an abnormal immune response and, when stimulated, produce an overabundance of substances called cytokines. These cytokines lead to numerous immunological processes and result in increased inflammation in the skin that is then sensed as an itchy sensation in the dog, which, in turn, results in the desire to scratch.
In addition, allergic patients have an abnormal cutaneous barrier that leads to increased exposure of environmental allergens, which are able to penetrate the skin more readily and initiate the allergic reaction.
Clinically, pollen or environmental allergies are those most commonly recognised by veterinarians. They are usually manifested as itching to the paws, face, ears or armpit areas and may be seasonal or non-seasonal.
“Secondary infections, which can be caused by either bacteria or yeasts, are commonly associated with underlying allergies and these are usually manifested as red papules (rash) or pustules (pimples),” says Dr Muse. “This secondary complication will increase the level of itching in most allergic patients.”
When it comes to treating the symptoms of an environmental allergy, Dr Muse says there are many options.
“There are multiple different oral and topical approaches that are important in helping to manage symptoms of allergies short term, but long-term allergy testing and successful immunotherapy (either subcutaneous injections with very small needles or oral drops) is one of the safest ways to try to control the symptoms of allergic skin disease.”
Food allergies (although much less common than people often believe) can also cause similar changes. According to Dr Muse, no reliable testing exists to distinguish food allergies, and switching commercial diets is insufficient to confirm them.
“Changing diets to either completely novel protein diets (such as kangaroo, goat, horse etc) or hydrolyzed protein diets (in which the proteins are manipulated to a very small amino acid component rendering them less likely to stimulate an immune response) are the best ways to document the presence of food allergies,” he says.
Home-prepared food trials that remove all ingredients to which the pet has been exposed can also be used. While ingredients such as grains, corn or wheat can cause allergic responses, these are much less common than the protein triggers in diets such as chicken, beef, egg, fish, lamb etc.
Flea allergy is associated with itching to the back and around the tail-head and rear legs of dogs, says Dr Muse.
“In the case of flea-allergic patients, the flea bite that allows for salivary antigen to be inoculated under the skin is the trigger for flea-induced allergic clinical signs,” he explains. “The longer the flea sucks blood from the dog, the more salivary antigen that is transmitted into the allergic dog and the more severe the reaction is in a flea-allergic patient.”
Aggressive flea control is critically important in flea-allergic patients. Anything that causes increased itching (even if the pet is not flea allergic) will lower the “itching threshold” and cause the other allergies to manifest, which, in turn, will lead to increased secondary bacterial or yeast infections.
Dr Muse says flea-allergy dermatitis is very common in allergic patients in which flea control is either sporadic or incorrectly or inconsistently applied. Clinically, flea-allergy dermatitis is associated with itching to the back, tail-head and down the rear legs of dogs, akin to flea allergy.
“Flea control is critical in managing flea-allergic patients and there are numerous products that have become available over the last few decades that have made flea control much more readily accomplished. The keys to flea control are using products with rapid kill or incapacitation of the flea, which allow for minimal flea feeding times resulting in less flea salivary antigen into the skin of the flea-allergic patient,” explains Dr Muse.
What is best to treat flea allergies?
“It is an oral product that is suitable since most allergic patients need to be bathed routinely to help decrease allergen exposure and to help reduce the tendency for secondary bacterial or yeast infections. Topical products may be affected by routine bathing with shampoos that are often used by dermatologists and veterinarians in managing allergic skin disease.
“Lastly, NexGard has very good palatability and has relatively low incidence of gastro-intestinal upset, which increases client compliance and makes administration easier.”
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