TL;DR
Pet allergies are increasingly common and rarely have a single cause. Food allergies are diagnosed through strict elimination diets, while environmental allergens — from pollen to dust mites to storage mites in dry kibble — are managed through testing, hygiene habits, and hyposensitization therapy. Pharmaceuticals and biologics can relieve symptoms, but the broader goal is to reduce a pet’s total allergen load over time.
“Nothing about allergies is easy,” says Dr. Laura Weis, DVM, CVH, of Doylestown Veterinary Hospital. But everything about them is illogical.
“An allergy is just the immune system reacting to things it should perceive as harmless,” Dr. Weis explains.
It’s almost like the dog that jumps when the vacuum cleaner roars to life or thunder cracks just outside the window. The cause is benign, but the reaction is all too real. And scary. And with allergens that cause itching, redness, and more — quite miserable for everyone involved.
And, unfortunately, they’re on the rise.
Pet Allergy Awareness Month, recognized each May, works to educate pet parents about increasingly common allergies in our pets — itchy skin, ear infections, incessant scratching — and what to do about them.
Back in the day, if a veterinarian examined an itchy dog, they looked for fleas, Dr. Weis says. Today, flea allergy dermatitis is rarer and largely controlled with flea and tick preventives. What’s replaced medicinal treatment is a concept borrowed from human medicine: total load theory. The idea is that a dog or cat can tolerate a certain amount of allergens before their immune system goes haywire and symptoms erupt.
Modern allergy treatment, Dr. Weis says, isn’t about a cure.
“It’s not about never being allergic again,” she says. “We’re often trying to reduce that load.”
When You Itch What You Eat
Tackling the nutritional side of allergies isn’t a walk in the park, but it is typically the path of least resistance, Dr. Weis says.
When a food allergy is suspected, it’s often a non-seasonal occurrence — though the symptoms may be the same.
“It can be itchy ears. It might be overall skin inflammation. Sometimes with or without gastrointestinal signs,” Dr. Weis says.
While tests do exist for food sensitivities, they’re not always entirely accurate. Instead, diagnosis frequently involves strict adherence to a novel protein diet — “You definitely need help picking those out,” Dr. Weis says — or a hydrolyzed protein.
“Hydrolyzed diets consist of proteins that are cut into tiny pieces, ensuring the immune system doesn’t recognize it as, say, chicken or soy or fish,” Dr. Weis explains. “You have to be very strict. No flavored medications or treats for about eight to twelve weeks. That will tell you what component, if any, of a pet’s allergies are due to a food problem.”
Environmentally Unfriendly
The flip side of “total load” typically centers on environmental factors, Dr. Weis says.
Atopic dermatitis is often caused by outdoor irritants that stem from grass, pollen, and trees, while indoor allergens like dust mites wreak more consistent havoc on the susceptible.
“We find a lot of dogs are allergic to dust mites or to food storage mites or molds,” Dr. Weis says. “Even cat dander. And so, you can have a seasonal pattern with an environmental allergen, but some of the indoor allergens are year-round, causing pets to be constantly exposed.”
“Storage mites are particularly tricky,” she says — largely because almost all dry foods are teeming with them, as are human consumables like grains, processed dried foods, legumes, and cereals. At its heart, it’s a management issue: HEPA filters, replacing kibble with canned and fresh foods, and keeping pets away from people treats are a help.
“It’s a tricky business,” Dr. Weis says.
“Freezing will kill the mites,” she says. “But it doesn’t get rid of them. We see a lot of this, and I don’t think we saw as much in the past.”
Testing for environmental allergens, at least, is simple, straightforward, and quite sensitive. These blood tests guide veterinarians in detecting outside pollens and grasses.
It’s all about first steps, says Dr. Weis. “You know, just wiping your pet off when they come inside, or cleaning their feet off to get the pollen off of them.”
Testing information is also invaluable as it allows for the creation of hyposensitization vaccinations — or sublingual therapy.
“This is based on the theory of slowly exposing the immune system to tiny amounts of the things a pet is allergic to. Then, gradually, over time — usually over a period of 18-24 months — we increase the strength of those sublingual drops to help relax the immune system’s response.”
This typically doesn’t remove the allergy, but it makes it much more manageable.
Other allergens exist, Dr. Weis says — but they’re more readily located and controlled.
Contact dermatitis, for instance, can be caused by household cleaners, herbicides, or pesticides that people put on their lawns. Pet bedding, too, can trigger it, or even synthetic carpeting.
The good news? For every itch, there’s typically a biological or pharmaceutical scratch.
Just What the Doctor Ordered
Pet allergies are such a huge part of contemporary veterinary practice that interest in both biologics and pharmaceuticals is booming.
“There are a number of different pharmaceuticals that, in one way or another, suppress broad or targeted parts of the immune system,” Dr. Weis explains. “There are also injectable biologics that block the expression of itchiness and inflammation. These treatments don’t really address the root of the problem, but they’re sometimes necessary if a pet is miserable.”
Antihistamines, she notes, are also an option — though a relatively mild one. “We’re always very happy if we’re able to use them with pets, because in a lot of cases they just don’t control the allergies.”
For its part, Doylestown Veterinary Hospital & Holistic Pet Care endeavors to take both conventional and holistic approaches to allergies.
“We try to feed patients an anti-inflammatory diet and supplement with things like Omega 3s. We also look at the gut microbiome. Approximately 70 percent of our immune system functioning originates in this complex environment. Addressing imbalances in the microbiome is often a part of helping to normalize immune functioning.”
Herbal therapies, acupuncture, and homeopathy are also employed, targeted at regulating immune systems and helping them to become less reactive, Dr. Weis says.
“The problem with allergies is that they typically get worse as the years roll on, and a pet often develops multiple new allergies,” she explains. “Because of this, their allergy season lengthens, and symptomology intensifies.”
“We want to create a more homeostatic balance.”
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FAQ
What are the most common allergy triggers in pets? The big three are food, environmental allergens (pollen, grasses, dust mites), and contact irritants like household cleaners or synthetic carpeting. Indoor allergens such as storage mites and mold can cause year-round symptoms, while outdoor triggers tend to be seasonal.
How do I know if my pet has a food allergy? Food allergies often show up as itchy ears, skin inflammation, or gastrointestinal issues — and unlike seasonal allergies, they tend to occur year-round. Diagnosis typically involves an elimination diet using a novel or hydrolyzed protein for about eight weeks.
Can pet allergies be cured? Generally, no — but they can be managed effectively. Treatments range from dietary changes and HEPA filters to biologics, pharmaceuticals, and hyposensitization therapy. The goal is to reduce the total allergen load, so symptoms stay manageable.
What is total load theory? Borrowed from human medicine, total load theory holds that a pet can tolerate a certain cumulative number of allergens before symptoms erupt. Treatment often focuses on reducing that overall burden rather than eliminating any single trigger.
