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Does My Pet Have Allergies? Part 2: Which Allergy Tests are Worth It?

Updated: Nov 4, 2022

So your pet is showing allergy symptoms, but so many of those symptoms look exactly the same, even when they come from different sources. Is it chicken? Is it pollen? Is it chicken AND pollen? Getting a direct answer for what precisely is causing the allergy could finally relieve your pet of those painful and disconcerting flare-ups, but be aware: not all allergy tests are created equal.

Going in for allergy tests can often be a long, complex, and expensive process, occasionally without a satisfactory conclusion. Getting to the bottom of an allergy mystery can take a bit of detective work, and it might take you down avenues you wouldn’t expect—or vice versa, there might be some tests you think your pet needs but might not be worth your time or money. In part 2 of our allergy blogs, we’re taking a look at the pros and cons of some of the more well-known tests for the allergy plaguing your pet.

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Does My Pet Have Allergies? Part 2: Which Allergy Tests are Worth It?

Want the Quick Synopsis? (TLDR)

  1. Currently, the only reliable way to tell if your pet has food allergies is to go through a well-constructed and dedicated food elimination diet trial, with a subsequent food “challenge” under veterinary supervision. (A food “challenge” is when your pet goes back to their original food once symptoms have subsided to make sure it was actually the food causing the issue.)

  2. On the other hand, the most reliable way to determine if your pet has environmental allergies is to work with your veterinarian to eliminate all other possibilities of conditions that may present in similar ways to allergies, with a potential referral to a veterinary dermatologist specialist.

Food Allergies

As we mentioned in our previous allergy blog, while true food allergies are relatively rare, solving them can be a stressful process for pets and pet parents alike, leaving you yearning for an easy solution. While it might be tempting to sign up for every food allergy test on the market, there are some important considerations you need to take before running the full gamut of tests.

1. Elimination Diet Trials

Often considered the gold standard, this is—to date—the only test that reliably diagnoses food allergies and intolerances (call that a two-for-one!) (7,13,14,17). Of course, there’s always a downside: elimination diets require strict dedication and self-control, which can be challenging if your dog or cat is a professional scrounger and/or has their PhD in begging. It also means everyone in your household has to be on board: no pet store treats, no scavenging on walks, and no pets hoovering the kitchen floor. Elimination diets can take a while to get concrete results, but they can provide invaluable information when done correctly.

1. The first step requires some reflection and homework. Start making a list of every food your pet has ever eaten—and yes, we mean everything. Think back on treats, table scraps, pet store visits, and boarding locations. Don’t be afraid to make phone calls to figure out exactly what your pet has been eating! This may seem excessive, but for an elimination diet to work, you need to start your pet on a protein they’ve never had before. Some vets may prescribe a hypoallergenic or hydrolyzed diet (where processing creates a chemical break down of proteins into particles small enough that the immune system won’t respond to them). We recommend using a fresh, raw, and limited ingredient diet for the best results.

See our limited ingredient Complete Meals for Dogs, and Complete Meals for Cats! With so many protein options, there’s sure to be a flavour they’ll love!

Red Dog Blue Cat Complete Meals for Dogs and Cats

2. Time to commit: once you’ve found a protein your pet hasn’t encountered before, plan on feeding this food and nothing else for 6–12 weeks (2,13,14). The hardest part about this will be constant vigilance, but hopefully, it becomes routine quickly. Remember that even just licking a plate, the kitchen counter, or another pet’s bowl—even if they’re done eating and you can’t see any food left!—can set off the whole experiment. Water bowls can also become contaminated if another pet drinks from them after eating! (2)

3. Okay, you might be thinking, no treats? What’s the point of having a spoiled fur-baby if you can’t actually spoil them? Normally, treats are off the menu on an elimination diet, but there are a few exceptions:

  1. Vegetables are acceptable if your pet will eat them (2).

  2. Bananas, canned pumpkin, sweet potato, or almond butter can be used to sneak medications if needed (2).

  3. While fruits and vegetables are ideal, you can give meat treats so long as it’s a single-source protein of the same type you’ve selected for their diet. For example, if you choose duck as your protein, freeze-dried duck liver, duck meat, or even duck feet can make a tasty little treat without disrupting the diet.

4. Start an “itch” journal! Note the location, size, and severity of any scratchy spots or lesions you find on their body, and keep track of them over time. Make a scale (e.g. 1–5 or 1–10) on how much they seem to be itching and licking, and monitor to see if it changes. Taking pictures will also help when you go to the vet! Speaking of which…

5. Make regular check-ins with your vet or veterinary dermatologist every 2–4 weeks! Gradual day-to-day changes are hard to notice (even with your itch journal), but your vet can use multiple visits to gather an approximate trend of their recovery progress. They’ll also help you keep on top of things like infections that may need additional treatment along the way (2).

6. Watch for disappearing symptoms. If it turns out that food allergies are actually responsible for your pet’s symptoms, you should see GI symptoms improve in around 2 weeks, while skin reactions may take 6 weeks or longer to fully heal (13). Cats should stay on their elimination diet for 6 weeks, and some dogs may need to be dieting for 8–13 weeks before you begin to see a definitive improvement (13,14).

7. Go back to your old diet. The only way to know with near certainty it was the food causing the reaction is to feed the old food after you’ve seen improvement on the elimination diet. This is called a food “challenge.” If skin irritations come back within 2 weeks of reverting to the original food, you can confidently conclude that some ingredient in that food is causing the problem (2,7,8,9,13,14).

  1. But which ingredient? True allergies are generally reactions to proteins; intolerances (which look similar to true allergies but are not due to responses from the immune system) are more often reactions to additives, dyes, or preservatives (2,11,13,14). This is why we recommend using a limited ingredient diet of raw, fresh foods—there are simply fewer ingredients to narrow down!

  2. Apparently, it’s currently “acceptable” in the pet food industry to have a 6-month lag between changing a recipe and updating the labels. We disagree with these standards, so contact the manufacturer if you’re not sure! RDBK is proud to have “live” labelling, so every label accurately reflects your pet’s current meal.

8. If your pet’s symptoms return, change back to the diet they improved on for another 6–12 weeks. Once their symptoms are gone on that diet, then you may try another different protein based on your vet’s recommendation. This way, you’ll be able to slowly start weeding out what your pet can and cannot tolerate!

Should You Use an Elimination Diet for Food Allergies?
  • Relatively inexpensive (compared to other options)—the only cost is the food and vet visits

  • May completely resolve skin issues!

  • Difficult to do properly—time-consuming, and requires a lot of commitment

  • Some trial and error, especially with unknown diet histories

  • Catching your pet sneaking off-diet foods may require you to start over

  • Some novel proteins can be expensive, depending on what your pet has had before


Highly recommended for food allergy and intolerance testing

Blood Serum Food Allergy Testing for Pets

2. Blood Serum Testing

Labs that test for other allergies will often include some foods in their panels. While this can seem like a “two birds with one stone” kind of situation, elevated antibodies to certain foods in blood tests (indicating allergies) don’t always match up with your pet’s real-world reactions (13,14,17). For example, when samples from healthy dogs were sent to some of these serum testing labs, they came back with positive results even when the dogs showed no clinical signs of food allergies whatsoever (13). Less research has been done for cats, but because the mechanism for reactions is similar in cats with skin issue reactions to food, we can make the same assumption of unreliability for them, too (14).

Should You Use a Blood Serum Test for Food Allergies?
  • Simple—just a quick blood draw!

  • Non-invasive

  • Unreliable for food allergies; a positive result does not confirm actual allergies

  • Difficult or impossible to replicate the results

  • Unreliable for predicting reactions to specific foods

  • Expensive! Blood serum tests can cost anywhere between $200–$700, sometimes more


NOT recommended for food allergy or intolerance testing

3. Saliva Testing

The idea behind this testing is that different antibodies to food allergens first show up in saliva before they become the slightly different bloodstream antibodies involved in allergic responses. In theory, this would allow you to catch a potential allergy before even seeing clinical signs, saving you and your pet some unnecessary misery! But like we talked about in blood serum testing, just because a sample shows high antibodies towards a particular food doesn’t mean your pet is allergic to that food. One study submitted samples from dogs with known allergies, non-allergic dogs, and water samples, all of which came back with false and non-repeatable results (19). While the theory behind this type of testing is interesting and deserves more study, it isn’t reliable enough yet to trust the answers it gives about our pets’ potential allergies (21,28).

Should You Use Saliva Test for Food Allergies?
  • Easy to collect samples

  • Can be done at home

  • Unreliable results

  • Science isn’t fully in on testing methods

  • May only be looking for intolerances instead of food allergies (but the reliability is just as questionable)

  • You may need a veterinary consultation to interpret the results

  • Expensive—anywhere between $150–$380 or more


NOT recommended for food allergy or intolerance testing

4. Hair Samples

There are currently no hair tests for allergies or intolerances used by veterinary dermatologists. Full stop. It’s easy to fall into a black hole of endless links when looking for information on this method of testing and still not get any concrete answers about how exactly it works. You’ll find vague statements like “it creates a profile of energies that radiates from a person or pet” (26) or “a bioresonance test for dogs is a natural method used to detect and recognize possible allergies and what is causing them with the help of electromagnetic waves” (25). While that sure sounds fancy, it falls definitively within the range of untested, unproven science.

Testing for allergies means you’re looking for specific antibodies…which don’t exist in hair samples (20). While some companies say they’re only looking for intolerances, not allergies, they still don’t explain exactly how they’re testing for them, and the results can vary wildly. In one test, samples of synthetic hair from a stuffed animal were sent along with samples from both healthy and allergy-affected cats, and the labs were unable to tell the difference between the three (14). So, not the most promising technology at the moment.

Should You Use Hair Sample Testing for Food Allergies?
  • Super easy—you’ve probably got enough pet hair to spare!

  • No clear information on testing methods

  • Not a proven testing method for allergies or intolerances

  • Results vary between the same sample, and fake hair samples produced results


NOT recommended for food allergy testing

Allergy Hair Samples for Dogs and Cats

Environmental Allergies

An important note here is that testing for environmental allergies doesn’t actually confirm environmental allergies or atopic dermatitis. Instead, these tests tell your veterinarian which allergens they should be targeting with specialized serums (2,4). These serums are designed to slowly desensitize your pet to some of the more reactive substances they may be getting exposed to. Alternatively, some companies also make sublingual drops to go under the tongue for pets (or owners) who are uncomfortable with needles. There are two tests that can fairly accurately determine what allergens should make up the serum, but only AFTER a diagnosis of atopy/atopic dermatitis (or environmental allergies) has been made.

How Do You Get a Diagnosis of Atopy/Atopic Dermatitis?

By now, you may have realized that nothing is cut-and-dry with our pet’s allergies, and diagnosing atopy is no different. For a proper diagnosis, your vet becomes a detective: it starts by ruling out all other conditions that may be causing the symptoms, including (but not limited to) performing flea checks, skin scraping, cytology, and elimination diet trials (4). These tests need to come back negative before proceeding to an allergy test, which will serve to determine what allergens might be causing the problems so your vet can develop an individualized immunotherapy allergy serum for treatment. (4,13,14).

The complexity of a diagnosis is why it generally takes so long for your veterinarian to come to a conclusion. Your pet WILL need to go through a thorough workup to get to this point, which requires time, patience and money (4,13,14). Jumping straight to testing might not be in your pet’s best interest, as much as you may feel like you need an immediate answer. We’ve mentioned before that occasionally, normal, healthy pets will show positive reactions to allergy tests, so you need to pair these tests with your pet’s environmental history, clinical presentation, and a veterinarian’s assessment for the process to be worthwhile.

Additionally, the whole goal of doing an environmental allergy test is to follow through with immunotherapy treatment afterwards, which involves either giving injections at home or an oral serum on a regimented schedule for years, possibly the remainder of their life. If this isn’t a commitment you’re prepared to make, then going through testing might not be the best investment for you and your pet. Still, getting answers through allergy testing can give some insight into whether your pet can avoid particular allergens. However, it won’t eliminate other treatments that might be necessary if flare-ups, you know, flare-up. (1,3,4,5,6).

1. Blood Serum Testing

Unlike with food allergies, blood serum testing for environmental allergies is a bit more reliable. By testing a blood sample collected at your veterinary hospital, vets can determine which allergens should be included in serums specific to your pet. This is in the hopes that outward clinical reactions to environmental allergens like dust, pollen, molds, dander and mites are eventually reduced or eliminated (1). ASIT (Allergy-Specific Immunotherapy) is the only therapy for atopic dermatitis that changes the disease's progress by using the body's biological mechanisms. It's also viable long-term with a low possibility of side effects (1).

Should You Use Blood Serum Tests for Environmental Allergies?
  • Non-invasive

  • Great for anxious or fearful pets that cannot tolerate sedation needed for other tests

  • No need for a specialist—any veterinary practice can do this!

  • Labs can tailor testing to regions where the pet lives for more specificity

  • Dependent on lab quality control measures, so ask experts for reliable labs for the area

  • Expensive—initial testing can cost between $200–700

  • Treatment requires continual serum purchases, which can be costly

  • While the frequency of injections can be reduced over time, this is often a lifelong treatment

  • Flare-ups can still occur and may require other therapies such as oral medications or topical treatments

  • Approximately 50% of pets that respond to therapy only show mild improvement (3)

  • Approximately 25% of animals do not respond to the therapy at all (3)

  • Best results occur if started early in the disease process


Cautiously recommended for treatment of environmental allergies

Intradermal Skin Testing (IDST) for Pets

2. Intradermal Skin Testing (IDST)

Generally done by a veterinary dermatologist, intradermal skin testing involves shaving a square of hair on your pet and making a grid of dots to mark where each allergen is injected (3,17). A small amount of each allergen, a positive control of pure histamine, and a negative saline control are injected into the marked site (3,17). After a set time, the grid is evaluated for reactions, and the areas with the highest response are selected to be part of the prepared allergy-specific immunotherapy.

Should You Use Intradermal Skin Tests for Environmental Allergies?
  • Quick results

  • Utilizes local knowledge of veterinary dermatologist

  • Can be used for a more customized treatment plan if the dermatologist makes the serum, compared to one made by a lab

  • The test can be done with varying dilutions of allergens for more accurate results

  • The test is administered to the organ that is being affected by the allergy (the skin) rather than through the blood.

  • Requires a referral to an experienced veterinary dermatologist

  • Can be expensive

  • May require sedation

  • All anti-itch medication must be stopped prior to administering this test (sometimes for 2 weeks or more), which could leave your pet uncomfortable for that time (4,5,6)

  • Similar to blood serum testing, while the frequency of serum needed may decrease over time, this is often a life-long treatment

  • Other therapies during times of flare-ups such as oral medications or topical treatments may be needed (1,3)

  • Approximately 50% of those pets that respond to therapy only show mild improvement (3), and 25% of animals do not respond to the therapy at all (3)

  • Best results occur if started early on in the disease process (1,4)


Cautiously recommended for treatment of environmental allergies

3. Hair & Saliva Testing

For the same reasons these methods are not recommended in food allergy testing, hair and saliva tests cannot be validated for environmental allergies. A reminder: the antibodies that react to allergens are not present in hair, and saliva testing continually produces incorrect results with unsubstantiated testing methods (18,19,20,21).


NOT recommended for environmental allergy testing

How to Stay Ahead of Allergies in Dogs and Cats

Staying Ahead of Allergies

While it can take a lot of time and effort to determine allergies in your pet, just having a diagnosis isn’t the end of the struggle: true allergies are lifelong and require lifelong management. The best defence we can offer our pets is quality nutrition and supplements that support the immune system, microbiome, and general health, all alongside appropriate treatments and lifestyles that work for them individually. If you suspect your pet has allergies—or at least something that looks like allergies—we cannot recommend enough that you try out a holistic veterinarian in your area and get to the bottom of the issue as soon as possible!


Want to Check Our Sources?

  1. Fadok V. Allergy Testing and Immunotherapy. In Medical FAQs. Jan 4, 2013 (published), July 6, 2017 (revised). Accessed at members page. - Fadok

  2. Griffin CE. Dermatologic Diet Trials: Mistakes & Tips (SA092). Western Veterinary Conference 2020, Animal Dermatology Group, San Diego, CA, USA - Grif

  3. Brooks W. Immunotherapy for Allergies in Dogs and Cats. Published 11/20/2006, reviewed/revised 05/11/2021. Accessed on Jan 25, 2022 - VetPart

  4. Hensel, P., Santoro, D., Favrot, C. et al. Canine atopic dermatitis: detailed guidelines for diagnosis and allergen identification. BMC Vet Res 11, 196 (2015). - BCVet

  5. The VIN Dermatology Consultants. Atopic Dermatitis in Dogs. Published 09/15/2003, reviewed/revised 04/21/2021. - VP1

  6. Brooks W. Allergies: Atopic Dermatitis (Airborne) in Dogs and Cats. Published 01/01/2001, reviewed/revised 01/05/2022. - VP2

  7. Werner Resnick A. Food Allergy: Dr. Google Debunked. Wild West Vet 2019. Accessed at members page. -DrG

  8. Mueller, R.S., Olivry, T. Critically appraised topic on adverse food reactions of companion animals (4): can we diagnose adverse food reactions in dogs and cats with in vivo or in vitro tests?. BMC Vet Res 13, 275 (2017). - Mue

  9. Brooks W. Food Allergies in Dogs and Cats. Published 01/01/2001, reviewed/revised 06/11/2021. - BWF

  10. Brooks W. Itch Relief for Dogs and Cats. Published 01/01/2001, reviewed/revised 06/21/2021. - BWI

  11. Tater K, C Laporte. Diagnosing Cutaneous Adverse Food Reactions (Food Allergies). Published March 23, 2021 - ??? - Tater

  12. White SD, KA Moriello. Allergies in Dogs. Merck Veterinary Manual Reviewed/revised Jun 2018, last modified Sep 2020. - Merck

  13. Tater K, C Laporte (revised) Food Allergy (Canine). On VINcyclopedia of Diseases. Published 07/07/2012 - FAC

  14. Tater K, C Laporte (revised) Food Allergy (Feline). On VINcyclopedia of Diseases. Published 07/08/2012 - FAF

  15. Dell D. Definitions For Atopy, Contact Dermatitis, And Environmental Allergy. 11/06/2017. VIN Members discussion boards - VINDisc

  16. Wurlod V. How to Diagnose Canine Ananphylaxis in Your Emergency Room (SA129). Western Veterinary Conference 2020. Baton Rouge, LA. - VINana

  17. Lieberman JA, Sicherer SH. Diagnosis of food allergy: epicutaneous skin tests, in vitro tests, and oral food challenge. Curr Allergy Asthma Rep. 2011 Feb;11(1):58-64. doi: 10.1007/s11882-010-0149-4. PMID: 20922509. - PM1

  18. Wünhrich B. Unproven techniques in allergy diagnosis. J Investig Allergol Clin Immunol. 2005;15(2):86-90. PMID: 16047707. -PM2

  19. Coyner K, Schick A. Hair and saliva test fails to identify allergies in dogs. J Small Anim Pract. 2019 Feb;60(2):121-125. doi: 10.1111/jsap.12952. Epub 2018 Oct 29. PMID: 30371955. - HairSaliva

  20. Cafasso J. How to Tell if you have a Food Allergy. Nov 28, 2018. - HL

  21. Niggemann, B. and Grüber, C. (2004), Unproven diagnostic procedures in IgE-mediated allergic diseases. Allergy, 59: 806-808. - Nigg

  22. Roudebush Philip, W. Grant Guilford, Hilary A. Jackson. Adverse Reactions to Food. In: Small Animal Clinical Nutrition. Mark Morris Institute, 5th ed. Ch 31 pp 609-635, Jan 1, 2010. - SACN

  23. The Microbiome - AnimalBiome. Accessed on Jan 31, 2022 - AB references, and possibly

  24. Dodds, WJ, DR Laverdure. Canine Nutrigenomics: The New Science of Feeding Your Dog for Optimum Health. Dogwise Publishing, Jan 13, 2015 - Dr Dodds

  25. Dog Insider Website. Accessed on Jan 10, 2022.

  26. 5Strands Website. Accessed on Jan 10, 2022.

  27. Mondo E , Giovanna Marliani, Pier Attilio Accorsi, Massimo Cocchi, Alberto Di Leone. Role of gut microbiota in dog and cat’s health and diseases. Open Vet J. 2019 Jul-Sep; 9(3): 253–258.

  28. Dodds WJ. Diagnosis of Canine Food Sensitivity and Intolerance Using Saliva: Report of Outcomes. Journal of the American Holistic Veterinary Medical Association (JAHVMA). Volume 49, Winter Issue, 2017/2018.


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