When your pet presents signs of allergies – get a free Pet Allergies eBook
on September 14, 2016
Posted in News
Because pet allergies are so common, and the symptoms so annoying to pets, helping with allergies is one of the most common things veterinarians do. Only because there are so many different mechanisms for allergy symptoms does it seem like pet allergies can be complicated.
For the owner of the allergic dog or cat, allergies give cause to worry all the time – not just worry about when the next allergy attack will occur and what to do about it. A little extra time and research can get to the bottom of most allergies for most animals. The asthmatic cat can be helped. The itchy, atopic dog can stop scratching. The food allergy pet can find a diet that will alleviate the allergy symptoms. Sometimes it’s a matter of breaking the itchy cycle. Sometimes it’s as simple as a detoxification diet.
When a pet presents with signs of allergies, the first thing to do is review the three most common causes of allergies. Canine allergies usually present as skin disorders, but the symptoms can also be in the gut. Cats also get itchy skin disease, just less frequently than dogs.
Therefore, without diagnostics, it is quite difficult to tell if an itchy dog has atopic dermatitis, a food reaction, or both.
Before we go into the Diagnostic and “Do-it-Yourself” tips, here’s a list of some common terms:
“Allergen” – a substance that triggers an allergic response.
“Adverse food reaction” – any abnormal response to food.
“Food allergy reaction” – an abnormal reaction to food that is based on the immune system’s response to the food.
“Food intolerance” – an adverse reaction to food that is not based on an immune system-based response.
“Cutaneous adverse food reaction” – an abnormal reaction to food that manifests on the skin.
“Flea allergy dermatitis” – common in pets allergic to the actual flea bite. The allergy is to the flea’s saliva. For these dogs and cats, one flea bite can set off a whole cycle that can result in hot spots and skin rashes.
Once a diagnosis is made, it’s time to deliver the right treatment. There is no right or wrong treatment method – there is the method that works best for your pet, your budget, your situation, and your expectations. Below you will find various ways of testing which will make all the different for your pet and your family. Here’s an example just ho important the right test can be:
Ruling out fleas
Because fleas allergies are in the top three causes of pet allergies, a good starting place for all treatment involves a flea inspection. A flea comb does a great job of pulling fleas or the “flea dirt” from the pet’s coat.
Fleas like to hide in warm, dark places on the pet – around the tail, ears and armpits. Flea dirt is digested blood – when placed on a white surface in a drop of water, the “dirt” will dissolve and turn red. (It’s not really dirt; flea dirt is actually flea feces – yuck.) If fleas are found, the culprit for itch may have been found. Sometimes it is that easy.
An interesting thing that some owners aren’t aware of: for every flea found, there are usually one hundred hiding at various stages of development on the pet. Some owners see one flea and think it’s not a big deal. With a hundred hiding, one flea is a big deal in the flea-allergic pet.
Before the development of modern diagnostic methods, diagnoses were often made by response to treatment. With this empirical method (simply observing whether treatment is effective or not), veterinarians try a multi-pronged approach in attempts to find relief for the patient. Many times, this approach is successful.
Simply by monitoring responses to different treatment regimes, a diagnosis can be made. Part of implementing a multi-pronged approach includes flea treatment, as discussed above. Often, these treatments also include avoidance of common triggers, treatment for presumed mange mites, use of prescription diets and immunosuppressive therapy – these will be discussed below.
When many treatments are implemented at the same time, it can be hard to know what the cause of the allergy is; however, when one’s dog is suffering from bald, hot, oozing skin and no one can sleep due to constant scratching, relief is often what matters.
The most common test for allergies in dogs is a blood test, called a RAST – radioallergosorbent test. This test measures IgE levels in the blood and also determines if a patient is allergic to flea saliva, trees, weeds, grasses, molds, cats, dogs, humans, insects, and some household allergens. Sadly, some dogs can be allergic to humans and cat dander, and vice versa. From the information gained, desensitization shots can be formulated to help the patient.
The RAST test can measure IgE levels to foods, theoretically looking for a food allergy. But, as we discussed above, IgA is the most abundant immunoglobulin in the intestinal tract. IgA tends to be a more accurate measure of food sensitivities. By contrast, IgE testing for food allergies is only 50% accurate, at best.  The other shortcoming of this test is that most laboratories test for 30 common food proteins, so if the allergy/sensitivity lays outside of the tested proteins, it will go undetected.
On the upside, pets tested with the RAST do not need to be shaved (as they do with intradermal testing) and the pet does not have to stop taking medications which may be providing relief. On the downside, the test often takes one to two weeks before results are known, which can feel like a long time if your pet is suffering.
The skin-prick (intradermal) test is rarely performed in pets. Instead, veterinarians inject a tiny amount of a solution under the skin and look for a response – usually a raised, red bump – called a wheal. This test specifically measures IgE, and tests the same substances as the RAST. The advantage of the skin-prick test is that results are obtained right away. Disadvantages are that pets must stop taking anti-itch medications and, in most cases, the pet needs to be shaved for the test.
A study in cats found similar results when comparing RAST and intradermal testing. Interestingly, the results correlated well with their asthma triggers. As we can see, RAST or intradermal testing is not only for itchy dogs, but also asthmatic cats.
Skin Scraping & Mites
The purpose of skin scraping is to look for all the other reasons that make dogs and cats itch – primarily mites. One of the hardest things when dealing with itchy patients is knowing there can be a lot of other contributing causes, not just allergies. The skin scraping helps shorten the list. There are two commonly occurring mange mites in dogs: demodex and scabies. In cats, cheyletiella is the common mange mite, also called walking dandruff. Demodectic mange is often hard to find; a colleague of mine once performed 20 scrapings to find the mites he suspected were there.
How was this veterinarian so sure this particular dog had demodectic mange? The poor dog was itchy, had greasy skin and looked like it had raccoon eyes (hair loss around the eyes). While raccoon eyes does not definitively diagnose demodex, it does suggest to treat for mange. Demodex is sometimes itchy; while scabies and cheyletiella definitely make pets scratch.
One word of caution: cheyletiella and scabies are zoonotic which means they are transmissible to humans. Fortunately, they are easy to treat and they really prefer to stick with dogs and cats. Healthy human skin will repel most zoonotic infections; however, it’s still a good plan to let your healthcare provider know if your pet has a contagious bug.
At first glance, it seems extreme to take a skin biopsy for an itchy pet; however, there are times when initial diagnostics do not provide enough information. A skin biopsy yields a sample that penetrates deep into the skin environment. It’s surprising how many cases I have solved because I performed a skin biopsy. As I explained above, some of the mange mites are very hard to find. A biopsy has a better chance of finding mange if it is there, especially demodex. And, not all dogs fit the clinical presentation of mange.
Saliva testing in dogs, cats, and now even horses, is a relatively new testing method to determine food sensitivities. If you remember from the immunology section we discussed the different types of immunoglobulins. IgA is a secretory immunoglobulin produced mainly in the intestinal tract. For animals with food sensitivities, IgA may be a better measure of food sensitivity as compared to IgE. Currently, there is only one laboratory providing the saliva testing, Nutriscan by Dr. Jean Dodds in California. The Nutriscan test evaluates a saliva sample for both IgA and IgM antibodies to 30 different proteins. This testing has been very helpful for some of my food allergy patients.
Neurotransmitter testing is a modern, cutting edge test method to diagnose itchy skin when it is caused by the body’s own neurotransmitters. While most test kits are designed for humans, the research behind neurotransmitter testing was first conducted in animals; therefore, the results from neurotransmitter tests have equal validity in pets, even though it is an uncommonly performed test. I have had several itchy patients that I could not diagnose by any other testing method, and the neurotransmitter test provided the feedback we needed. The neurotransmitter test uses a urine sample.
Neurotransmitters are the chemicals that help nerves communicate. If neurotransmitters are out of balance, it can affect other parts of the body. Neurotransmitters are usually excitatory or inhibitory. If there is an overproduction of excitatory neurotransmitters, it can cause itch due to overstimulation. Likewise, if the inhibitory neurotransmitters are not produced in enough concentration, there is still too much stimulation, which can manifest as itch in other patients. The great thing with this testing is it may just provide the missing answer that other diagnostics have been unable to determine.
Checking body pH is wonderfully straightforward. Either the pet owner or the veterinarian can check both urinary and salivary pH. As mentioned earlier, neutral pH is 7.0. Normal urine pH should be slightly acidic, between 6.5 and 7.0. Salivary pH should be slightly alkaline, between 7.4 and 7.8. pH strips are available online, from health food stores, and some pharmacies. The most useful strips are the ones that range from 4.5 to 9.0. First thing in the morning, before a drink or food, wet one pH strip with saliva. Repeat with the first urine of the day. The pH readings should fall in the range above.
High salivary pH (alkaline) suggests there might not be enough stomach acid production. For some allergy patients, simply adding an acidifier (betaine – see the Western herbs section) can be quite useful.
Note: if your pet has a bladder infection, it can often be accompanied by very alkaline urine – in the 8.0 to 9.0 range. If you find your pet’s urine is within that range, be safe and have your veterinarian run a full urinalysis (urine test) to be sure there isn’t something more going on.
Until the advent of saliva testing, food trials were the gold standard to determine if a patient had food allergies.
Even today, food trials are still the preferred method to check for food allergies. Because it is difficult to differentiate between food allergies, food sensitivity, and food intolerance (as discussed above), sometimes it’s easiest just to perform a food trial.
In the food trial, the owner selects one protein and one carbohydrate that the pet has likely never eaten in its’ entire life. Just as Bentley ate tuna and brussels sprouts – novel foods for him – these foods could be goat, kangaroo, quail, emu, quinoa, Jerusalem artichokes or brussels sprouts, as examples.
Food trials are usually easier with dogs who usually have adventurous taste buds, whereas cats tend to be finicky about food. A relatively easy starting point for a food trial would be to use goat meat and quinoa as these ingredients are not common in pet foods.
Learn more about food allergies, Leaky Gut and specific diets, available as conventional treatment, “do-it-yourself techniques” as well as Alternative Treatments (Chinese Medicine) design to help you treat pet allergies, not their symptoms!
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Janice Huntingford, DVM, has been in veterinary practice for over 30 years and has founded two veterinary clinics since receiving her Doctor of Veterinary Medicine at the Ontario Veterinary College, University of Guelph. She has studied extensively in both conventional and holistic modalities. Ask Dr. Jan