Evidence-Based Canine Allergy Treatment

Allergies are an incredibly common, and frustrating, problem in pet dogs. Unlike humans, respiratory manifestations of environmental allergies are not usually very noticeable. Dogs with allergies get itchy skin, and they scratch like crazy as a result. The underlying inflammation and the scratching both lead to secondary infections, especially of the ears and skin.

There are several categories of skin allergies, including allergy reactions to fleas, to foods, and to general environmental allergens such as pollen, dust mites, and so on. There are, not surprisingly, a lot of myths about allergies, and a lot of CAM treatments recommended, as is always the case with chronic disease science does not yet have definitive cures for.  In the future I hope to address some of these, but right now I want to discuss some evidence-based recommendations for treatment of atopic dermatitis (AD: environmental allergies, as distinguished from flea or food allergies).

The veterinary dermatology community seems to have adopted not only the rhetoric but the actual practice of evidence-based medicine more effectively than the profession as a whole. There are a number of published evidence-based reviews of therapies for various skin diseases, and a new review recently appeared titled Treatment of canine atopic dermatitis: 2010 clinical practice guidelines from the International Task Force on Canine Atopic Dermatitis. (Olivry T, Deboer DJ, Favrot C, Jackson HA, Mueller RS, et al; for the International Task Force on Canine Atopic Dermatitis. Treatment of canine atopic dermatitis: 2010 clinical practice guidelines from the International Task Force on Canine Atopic Dermatitis. Vet Dermatol. 2010 Apr 23 [Epub ahead of print].) After discussing what is known about the cause and mechanisms of AD, the report reviews various treatments for acute and chronic atopy and grades the evidence and strength of the recommendations for them. I have reproduced the grading scales for evidence and recommendations and then collated the findings in the chart below.

Table 1. Categories of evidence and strengths of recommendation

Category of evidence

Ia. Evidence from meta-analysis or systematic reviews
Ib. Evidence from at least one randomized controlled trial
IIa. Evidence from at least one controlled study without randomization
IIb. Evidence from at least one other type of quasi-experimental study
III. Evidence from non-experimental descriptive studies, such as comparative studies, correlation studies, and case-control studies
IV. Evidence from expert committee reports or opinions or clinical experience of respected authorities or both
LB. Evidence from laboratory-based studies

Strength of recommendations

A. Directly based on category I evidence
B. Directly based on category II evidence or extrapolated from category I evidence
C. Directly based on category III evidence or extrapolated from category II evidence
D. Directly based on category IV evidence or extrapolated from category III evidence
E. Directly based on category LB evidence
F. Based on consensus from Specialty Task Forces
Modified from: Leung DYM et al. Ann Allergy, Asthma, Immunol 2004; 93:S1–21.

Therapy Recommendation Strength of Recommendation
Acute Flareup    
Identify & avoid allergens Treat for fleas, rule out food allergies, avoid known environmental allergens, beneficial  D
Antibiotics, Antifungals Topical or oral drugs for identified secondary bacterial or yeast infections beneficial  D
Bathing Probably washing more important than shampoo used, beneficial  B
Topical glucocorticoids Short courses very beneficial A
Oral glucocorticoids Short courses if symptoms too severe for topicals, beneficial  A
Antihistamines Not beneficial
EFA (e.g. fish oil) Not beneficial
Tacrolimus Not beneficial
Cyclosporin Not beneficial
     
Chronic Treatment    
Diet trial for food allergy Beneficial if food allergy part of problem  D
Flea Control Beneficial D
Allergy testing Skin or blood testing may detect allergens (not foods) that can be avoided or guide immunotherapy  C
Dust mite control Theoretically beneficial but unlikely to clinically help most dogs  C
Antibiotics, Antifungals Topical or oral drugs for identified secondary bacterial or yeast infections beneficial  D
Bathing Probably washing more important than shampoo used, weekly, beneficial  D
EFA (e.g. fish oil) Helpful in conjunction w/ other therapies, not alone, no particular dose or product, oral only; mildly beneficial  B
Topical glucocorticoids, tacrolimus Beneficial, some adverse effects especially older products  A
Oral glucocorticoids, cyclosporin Beneficial, lowest effective dose to minimize side effects  A
Injectable interferon Beneficial A
Immunotherapy (allergy shots) Beneficial  A
Phytopica (herbal) Steroid sparing effect Ib(evidence)
Antihistamines Not beneficial
Pentoxifylline Minimal benefit, risk too high Ia(evidence)
Misoprostil Minimal benefit Ia(evidence)
Tepoxalin Minimal benefit Ib(evidence)
Leukotriene inhibitors Not beneficial Ia(evidence)
Dextromethorphane Not beneficial Ia(evidence)
Capsaicin Not beneficial Ia(evidence)

Obviously, the text of the review discusses the details of these interventions and the supporting evidence (or lack thereof). The evidence is often of low quality and quantity, but the Task Force has effectively followed the principles of evidence-based medicine in basing recommendations on the best evidence that is available and acknowledging the shortcomings of this evidence where appropriate. Obviously, the strength of their recommendations, and the confidence we as practitioners place in them, should be proportional to the quality of the supporting evidence.

The therapies with the best-documented efficacy, glucocorticoids and cyclosporin, are of course those with the best understood side effects. There is no free lunch in physiology! However, it is also notable that the supposedly safer therapy almost universally recommended in general practice, antihistamines, have little to no evidence of meaningful benefit. It seems likely we give these out mostly in response to the pressure, from the owner and from ourselves, simply to do something. The evidence seems pretty clear that we need to give up this unsupported practice.

Essential fatty acid supplements (EFA, usually fish oils) do have some demonstrable efficacy, but their effects are relatively small and best used to reduce the need for other therapies, such as glucocorticoids, not as primary therapeutic agents. One herbal preparation seemed to have a steroid sparing effect based on a single well-designed clinical trial (Phytopica), but the Task Force was careful to state clearly “Whether or not similar observations would be made with other nutritional supplements has not been established, and care must be taken to not extrapolate these findings to other untested products.”

Such a review is very helpful for the ordinary vet in practice, and while the quality of the evidence is not what we would desire, having it reviewed and explicitly graded in this way is a fine example of how evidence-based medicine can and should be applied in the veterinary field even with the limitations we face.

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42 Responses to Evidence-Based Canine Allergy Treatment

  1. lyndee says:

    Good article thanks ! What are your thoughts on broadbased allergy treatment without the testing? See vetrespit.com.

  2. Bartimaeus says:

    It’s interesting that they don’t really cite any evidence against the use of antihistamines either. There is a brief discussion of the type 1 antihistamines in the paper, and why they are probably not effective in cases of chronic atopy (basically closing the barn door after the horse is gone). Type 2 or newer generation antihistamines are still histamine receptor blockers, and therefore probably would not work very well either, but may have longer half lives and cause less drowsiness. On the other hand, the side effect of mild sedation or drowsiness might be reducing scratching somewhat, leading to a perception of efficacy in some cases.
    It’s a bit disappointing that such a commonly used class of medications has so little evidence one way or the other.

  3. skeptvet says:

    Lyndee,

    Thanks for the question. The idea that immunotherapy might be beneficial even if the specific allergens the patient is reacting to aren’t known is a little counterintuitive. A broad collection of antigens might accientally include relevant ones, so it could work in that way. Or the theory the Respit folks seem to be putting forward, that the antigens don’t really matter, could also be true.

    I consider the evidence presented on the web site a bit of a red flag, though. None of the articles cited were actually studies of the theory or the product. They do indicate some limitations to intradermal skin testing, but limitations in the diagnostic test isn’t evidence for the proposed treatment. The site also presents personal experiences suggesting the approach works, but we all know how unreliable that can be as a way to evaluate a therapy one is selling.

    I would consider the approach plausible but unproven and experimental, and I’d be more inclined to recommend it if there were some published clinical trials examining it directly, or if there was at least a consensus in the vet dermatology community that the approach was appropriate. If nobody else is doing or studying this, the question “Why not?” becomes a big one.

    And I don’t see that it is the skin testing that limits immunotherapy use in my practice. People who reject immunotherapy generally do so because they don’t want to give the shots, not because they don’t test isn’t reliable.

  4. Stephen says:

    To Me…

    Here are Dog allergy Treatment Choices.

    > Ignore = Sad for Dog

    > Chance to High End / Expensive FOODs = FOODs only 20% of Allergy Source Vs Enviro = Real Cuplrits

    > Drugs = Mask Symptoms > Leaving progression of allergy intact to continue / exacerbate unabated.. Sad for Dog / Owner

    > Skin Test w/ Immuno > Time & Costly > But DeSensitizing Source / Effective > But SHOTs / Ouch

    > > RESPIT Immuno > Time & Small Cost > Allergen Shotgun approach = OK > Treats Allergy Load 80/20 of Offendng Allergens / Treating other non-offending makes no difference > But DeSensitizing Source / Effective… > But SHOTs

    RESPIT seems to be the Same but only Different for Less $ to PET Owner

  5. skeptvet says:

    Stephen,

    Obviously ignoring the disease is not a valid option. Novel antigen diets can lead to complete remission of signs in perhaps 20% of patients, and they are not all that expensive. In fact, you can make your own quite cheaply with some advice from a nutritionist and a little work. And even if they only cause partial resolution, that’s real improvement in quality of life for the dog.

    Medications don’t “mask” symptoms, they eliminate them by directly interfering with the excessive activity of the immune system. Since allergies come and go/wax and wane, symptomatic therapy may allow a normal quality of life with few to no side effects for many dogs, so I suggest your characterization of it is inaccurate and biased by your prejudices about medicines.

    Immunotherapy is time consuming, but I have yet to see a patient who objects to the injections, so while I’m sure some do this is not a fair generalization or a reason to dismiss this valuable therapeutic tool.

    RESPIT is theoretically plausible, and if it works it may well be a great option. However, in the absence of any clinical evidence that it works, it’s an experimental therapy, and the reality is most experimental therapies never live up to our hopes for them. I have no objections to testing it, but suggesting it is a better option than the other therapies you mention isn’t supported by the existing evidence.

  6. Stephen says:

    Per my above Comment…

    Thank You Dr. SkeptVet for sharing your Time / Advise & Frank Thoughts.

    I am sure that your Blog / Information is an invaluable resource to many.. many.. Pet Lovers.

    While I do not take exception to your Advise.. and perhaps I am a little against Med’s which do not address / treat the source of a disease.

    I am Business Trained / Get to / Fix the Source of the Problem .. and my understanding of ImmunoTherapy is all about DeSensitizing as many offending allergens as possible i.e. Reducing the Allergy Load.

    To me Immunotherapy is incredible … in that it actually gets to / desensitize the Source of a Patients Allergy Disease > Wow > And it is done virtually > Let Likes Treat Likes / Drug Free. > Producing Lasting Health & Quality of Life Benefits for Pet & Owners.

    Further, ( to me ) it is not out of the question for Animal, as well as Human Medical Professions to identify the “80/20 Usual Allergy Suspects” for a given geo-region and pre-mix vaccine accordingly.

    Sure .. there will be some “ Missed “ Allergens …

    Sure … there are bound to be some extracts to which the animal is treated but not allergic ( no clinical issues as a result )…

    But given allergy presence .. the ODDs are good that your Pre-mix formulation will actually “Hit” enough offending to be clinically effective.

    I guess it is all about .. “Skipping” the Skin Test … and the resulting custom vaccine formulation that follows…

    To me..
    While there may be a number of Vet’s who are more comfortable taking the Skin / Custom Vaccine route .. it is my casual impression that many more will find the Immuno-RESPIT Program is a Quick Go To Option for Pet Allergy Desensitization.

    While I fully appreciate that most NEW Therapies do not live up to their promises .. I believe that the RESPIT Program is not really “ Experimental “ but simply leverages what is already known about Immuno-Allergy toward a more streamlined / time & cost effective methodology .

    The fact that you have no objections to try ..speaks well …

    To me, far to often ..
    Human & Animal Medical Professionals wait for “Lagging Indicator” Study Results / or “further Studies Needed” before they act .. when.. at the end of the day.. they have Patients NOW who need help…and they can use their best medical judgment / years of experience and move forward …slowly… Today.

    I guess that is why they say > Practicing Medicine is as much an Art, as it is a Science.

    Wishing You & Your Furry Friends Health = Wealth Regards

    S

  7. Jon says:

    I applaud Skeptvet’s article and welcome the discussion about RESPIT. I am the veterinary dermatologist behind RESPIT. Stephen made some excellent points, not the least of which is that RESPIT is not as different from what is already being done by veterinarians as you might think.

    Let me explain. It is not uncommon for allergy tests, either intradermal skin tests or blood allergy tests to have positive reactions to dozens of items. What do veterinary dermatologists do when this happens? They select the things that they think are most important, based on the same criteria I used to select the items for RESPIT. They might say that they use individual exposure history, but after having done this for 20 years, I can tell you that even the best-informed and intentioned pet owners can’t give you much meaningful information about the level of exposure to various pollens or dust mites in their homes. And when general practitioners run allergy tests, I expect that most just take the advice of the testing lab to formulate the allergen, without any discussion.

    Further, serum allergy testing labs have a spotty history of quality control and reliability. Studies that have looked at reliability (repeatability and reproducibility) usually turn up significant problems with the tests (with a recent exception of several labs using the same methodology). The tests usually don’t agree with intradermal tests done on the same patient. How can veterinarians know which one is accurate for a given patient? According to conventional wisdom, it should make a big difference to treatment success to pick the “right” test, and in most studies it hasn’t.

    And, even when presented with identical test results, veterinarians are still going to make different decisions regarding what to include — it is not at all standardized.

    The bottom line is that conventional immunotherapy formulation includes a lot of subjectivity and variability. RESPIT will not replace allergy testing, it is just another option for those of us who no longer want to recommend an expensive test with questionable value, but still realize the benefits of immunotherapy.

    Jon Plant, DVM
    Diplomate, American College of Veterinary Dermatology

  8. skeptvet says:

    Dr. Plant,

    Thanks for contributing to the discussion.

    There’s no doubt that there are many weaknesses to the conventional immunotherapy approach, and as an alternative RESPIT seems reasonable. But of course I’m sure you understand the importance of controlled, published research in validating (or not) new approaches, as well as in convincing veterinarians of their legitimacy. As I mentioned in my post, the veterinary dermatology community is rather ahead of the rest of the profession in terms of produing good, evidence-based literature for those of us in general practice to base our clinical decisions on. Have you publishe,d or do you plan to publish, any RCTs or other clinical trials of RESPIT that would help us evaluate it?

    Thanks again!

  9. Jon says:

    I submitted a case series for publication 2-3 months ago. It is still in the hands of the reviewers. I have also explored performing a RCT with a non-inferiority design. There are some challenges in that design that I am trying to overcome, namely that we don’t have good efficacy studies on conventional allergen-sepcific immunotherapy available. One needs to know the variability in the expected response of the positive control in order to design a solid non-inferiority study.

    Regards,
    Jon Plant, DVM, DACVD

  10. skeptvet says:

    Yes, there are always challenges in designing a good RCT, aren’t there?

    It seems that the core question you would be trying to answer is “Is the clinical outcome of immunotherapy targeted at specific antigens as determined by IDST equivalent to or superior to the clinical outcome of non-specific immunotherapy based on general assessment of antigens likely to be relevant?” Or something like that. You would need to show that the Tx and control group did not differ in salient ways (severity/duration of disease, concurrent Tx, signalment, perhaps even the specific antigens they were sensitive to, which would involve testing both groups). Then you’d have to show that the Tx, evaluation, and followup was equivalent for both groups apart from the variable of interest. And, of course, there’s always the difficulty of blinding and the subjctivity of outcome measures such as pruritis scores etc.

    I certainly appreciate the practical difficulties. Still, I’d be very interested in the results if you are able to put together such a trial, since even imperfect evidence is valuable in our field where the kind of evidence human health care takes for granted is so seldom available.

    Thanks again for taking the time to comment.

  11. Cynthia says:

    My mixed breed 9 yr old 38lb, rescue dog named SAM (DNA test performed 2005- results: 25% cocker spaniel, 12.5% chow, 12.5% collie & 50% unknown) first diagnosed via pet derm specialist with severe environ & food related allergies. Diagnosis: foods process of elimination to identify reactions coupled with skin testing. Results = specific environ allergies (dust mites, fleas, grass, eucalyptus, dogwood, certain fibers, air, water, you name it). Treatment: homemade diet, shots, frequent baths, benedryl, avoidance of allergen aggitators. After spending “thousands of dollars”, LOOSING ALMOST ALL OF HIS FUR & 3yrs later with minimal to zero results, my vet diagnosed SAM having atopica dermatitis. Prescribed Atopica 100mg 1x/day, 3mg melatonin, flea prev progr & if needed; benedryl, wait an hr before feeding home diet(turkey or fish with brocolli & sweet potatoe plus supplements) . Frequent baths, cleaning often bedding, dusting & vacuming. Limit or avoid outside walks during high allergy season along with cephalexin antibiotics for major skin out breaks. Sam’s been on this program now for over 6yrs, his fur growth doubled & started showing positive results. So far so good. To date, Sam’s having more frequent skin flare ups having to take antibiotics almost every other month. Despite steam carpet cleaning (myself I might add) my 3800 sq ft home including stairs & upholstery, unless I ripped out every carpet in my house, vacum every piece of furniture & carpets to cut down on dust mites, additionally following above mentioned program “might” result in lesser outbreaks? My concern is Sam will eventually build a tolerance to the antibiotics. Vet recently tried him on generic Cipro. Cephalexin actually worked better. He’s starting to loose some of his fur again & appears to almost now be in chronic flare up mode with “maybe” sporatic 2-3wk reprive intervals. I’m at a loss!!! Should I be changing his diet to a different allergy diet, should I be bathing him daily, should Sam have to take antibiotics every day plus 100mg atopica or generic cyclosporin every day for the rest of his life?
    How can I minimize his outbreaks as well? Would love to hear suggestions.
    Appreciate your feedback & time. Cynthia

  12. skeptvet says:

    Allergies are, as you obviously know, a frustrating chronic disease. No matter what anyone say, they are not curable, but they can usually be managed effectively, though doing so can be very time, labor, and money intensive. I cannot give you specific advice for your pet, and you need to have a close and ongoing relationship with a specific veterinarian with whom you have good communication to manage a disorder like this. But I can give you my opinion about allergy therapy in general.

    You’ve done most of the things that are possible to do, but what you have to remember is there is no single fix, and the symptoms cycle from better to worse in response to lots of factors besides our treatments. So it take months of time to really evaluate if a new treatment is or is not helping. Most of the time we take our pets in when they are at their worst, so they sem initially to be better with treatment but some of that is because the naturall cycle of the symptoms was probably on the way down anyway. For long-term management, each thing we do turns down the volume on the itching a little, so the goal is to combine therapies in a way that overall reduces the symptoms as much as possible. Infections are a secondary problem, so treating them is necessary but won’t affect the underlying alelrgies most of the time. So a combination of medication (the cyclosporine is probably the best currently available for long-term use, with intermittant steroids at low doses for flareups, fish oil, and possibly anti-histamines), topical therapy (particularly bathing), dietary management (they absolutely can develop sensitivities to diets that initially helped, so if the symptoms worsen and they’ve been on the same diet for a long time, a change to a new protein source or a hydrolyzed protein diet might help) and possibly immunotherapy (i.e. allergy shots) are often needed to keep the symptoms to a minimum. Environmental control can help with some antigens, but in general for dogs with allergies to common things that are everywhere all the time, I believe this isn’t a very effective approach. And with all this, you will still have flareups and may sometimes need antibiotics and short courses of steroids, but I would think a frequency of 3-4 months would be a lot more reasonable than 2-3 weeks.

    If you didn’t have a great experience with your first dermatologist, you might consider finding another. They really do have more expertise and knowledge of how best to manage these difficult cases than those of us in general practice. Good luck!

  13. PFUDA says:

    Thank you skeptvet for this discussion. I am considering allergy shots for my dog and saw the website for Respit. Did they ever publish additional info/trials on the efficacy versus more targeted therapy? Seems if he submitted a paper in 2010, we’d have sonething by now..

  14. skeptvet says:

    Still no additional published data on Respit, and the debates between Dr. Plant and other dermatologists on the subject are still the same. We don’t know if this approach is as effective, better, or worse when compared with targeted immunotherapy.

  15. Art says:

    http://www.us.atopica.com/pdf/product-insert.pdf
    If cyclosporine has no evidence why does the FDA allow Atopica to have a atopy label?

  16. skeptvet says:

    There is Grade A evidence to support the use of cyclosporine in management of chronic atopy (see chart above). Peraps you were looking at the “Acute Flareup” section, for which it would not be beneficial?

  17. Art says:

    I wrote “My bad” and the spam filter told me it was to short and to go back and try again. I love it when a computer does the editing.

  18. v.t. says:

    WordPress is lonely, Art, and has a mind of it’s own. We should be glad it’s not d*mned autocorrect 🙂

  19. KLD says:

    Going to try oral RESPIT because my needle phobic dog will not accept allergy shots. Wish us luck. He is age 12, mixed breed, on Atopica with methylpred for flare-ups. I’m hoping to reduce or eliminate the hard core drugs.
    I appreciate the information above and am trying this with equal measures of skepticism and optimism.

  20. KLD says:

    Five months into oral RESPIT. No Atopica or prednisone for several months. I am cautiously optomistic that RESPIT may be working. However, the area where I live just went through the driest year in recorded history, so too early to know if RESPIT is working, or if nature lowered allergens to a tolerable level for my dog.

  21. KLD says:

    Hum? RESPIT not working, or is the allergen load just overwhelming my poor dog? I’m in The S.F. Bay Area where we never got a winter. This spring is spectacular. EVERYTHING is in bloom. My dog was feeling great until the beginning of March. He was on RESPIT and nothing else. First time in 10 years that he had been completely drug free. Then the allergies hit big time and now he is on the highest dose of methylpred that he has ever been on. Still can’t control the itching. He’s started to wet his bed at night.
    His vet has Apoquel on order. Can’t wait to try the next miracle drug.

  22. Stephen Love says:

    My dog, Bear, has been receiving the Heska oral desensitization product based on both intradermal testing results and blood testing for nearly 3 years (in addition to a 25mg. Hydroxyzine tab and a squirt of Omega Tri-V Liquid a/k/a fish oil, daily) with good results. “Good” means he hasn’t had any of the large, messy hot spots he experienced prior to beginning his treatment, but he did have a small hot spot on a hind leg early in the treatment that lingered for a year before simply disappearing. He has had the same sized spot on a front leg for a little over 2 months. He wears an e-collar, the spot heals, I (gratefully) remove the e-collar and all is well for a day or two, then he suddenly licks/chews the spot and the cycle begins all over again. It’s impossible to know when the spot is actually gone for good. Friends have been using Apoquel on their dog and are very happy with the results. Based on my dog’s situation as described herein, would Apoquel be a good option for us? If so, would it be used instead of or in conjunction with his current oral desensitization meds? Any feedback would be most appreciated. Thank you.

  23. skeptvet says:

    Apoquel can be helpful to dogs with persistent allergies, though there have been significant problems with availability that have limited its usefulness. Every situation is different, so I would recommend talking about the pros and cons of adding in this treatment with the vet who s managing Bear’s treatment.

    Good luck!

  24. Jessica Lobert says:

    This thread has been incredibly helpful. I have a 5 year old American Staffordshire Terrier that’s been on Apoquel for about 8 months now. Can anyone give information on long term side effects for this “wonder drug.” I’ve read some scary things about it, but I don’t know about the credibility of the info. Some layman’s terms on how apoquel affects the immune system would be helpful I think.

    Thank you,
    Jessica

  25. skeptvet says:

    Unfortunately, no one can give you any reliable information on long-term adverse effects because the drug hasn’t been in use long enough to follow patients for extended periods of time. The package insert provides data from the licensing trials. From a purely anecdotal perspective, few serious reactions have been see as the product has come into widespread use. However, the only way to know in the long run is to watch animals on it for many years, and that simply hasn’t been possible yet.

  26. Judy Rothauser says:

    My holistic vet says that apoquel has a 5% cancer rate.

  27. skeptvet says:

    Your holistic vet is making that up. In the original short-term safety studies, 2 dogs receiving Apoquel were diagnosed with cancerous tumors during the study, and one dog receiving the placebo was diagnosed with a cancer. Given the short duration of the study and the lack of difference between the Apoquel and placebo, it is very unlikely that Apoquel was the cause since.

    In the long-term safety study, over the course of a bit more than a year, 6/239 dogs did devlope different kinds of cancer. However, there was no placebo control, so we have no idea how many dogs would have developed cancer during the same period of time without taking Apoquel. And since the cancers were a variety of common diseases, it doesn’t look at all like an unusual rate of cancer diagnosis over this period of time.

    Since cancers develop all the time, some dogs on Apoquel will get cancer, but that doesn’t mean that the Apoquel is the cause. It is possible that this medication could increase the risk of cancer, as it is possible for every other medication, herb, or compound of any kind we use as a medicine. However, as of now there is no evidence to support this, and the 5% figure from the long-term safety study that your vet is using is totally misleading since there is no group of dogs for comparison wh weren’t given the medication.

  28. Vicki C says:

    I have been reading your blog today looking for info on diets high in refined carbs and yeast in dogs. My dog is older, min schnauzer spayed female. She has had history of gastric attacks usually diagnosed as pancreatitis but the blood work would often come back w/o any clinical signs of that…she developed serious skin problems–itching, hot spots–fungus. She tried antibiotics, steroids, antihistamines for over year w/o good results. Took her to dermatologist who basically said skin tests are often unreliable methods of allergy detection. We finally decided that she was allergic to chicken because changing that protein helped calm the itching. Switched to a Royal Canin RX diet w/venison and potato–high carb count and refined carb at that. And Apoquel–which I know has many stories about side effects (w/o scientific evidence–but the MFG doesn’t exactly want to spend any money proving it has a bad product)…Anyway–our dog had no quality of life before the Apoquel…so we weighed current positive vs future negative and are still on it…

    Now I think she is developing more skin issues–maybe yeast problems from too many carbs…still on the Apoquel but she has started licking her feet more, has two bumps/on her back that seem to be yeast infections. We are away from area where our vet is–will go back in two weeks. I have taken her off the dry kibble Royal Canin and dog biscuits (wheat flour) and will add more lean cooked beef to her diet and have found a canned food that is almost all rabbit w/few additives.

    What can you offer as info regarding diets w/higher refined carb amounts and problems w/yeast in dogs? We have tried many commercial foods and even home cooked trying to find her some peace–except raw. I don’t want her to go through those trials again…

  29. skeptvet says:

    There is no evidence that carbohydrates in food are a source of skin allergy problems. Of the three macronutrients (fat, carbohydrates, and proteins), proteins are the trigger for most allergies. Some plant proteins are allergy triggers (such as corn and wheat), which often confuses people since they see “corn” and “wheat” and think carbohydrates, but it is really the proteins that the body is reacting to, just as with animal proteins.

    In the case of food allergies, dogs genetically prone to develop food allergy reactions will, over time, develop reactions to the proteins they are exposed to, regardless of origin, There are no “good’ and “bad” protein sources, just familiar proteins (which the dog may or may not have developed a reaction to) and novel or unfamiliar proteins, which the dog is unlikley to be allergic to unless they are similar to proteins he or she has been fed routinely in the past.

    As for yeast, there is a type of yeast that normally lives on the skin of all dogs, called Malessezia. This can overgrow in dogs with allergy problems, and it may itself be a trigger for allergies in some dogs. However, this has nothing to do with the amount or type of carbohydrate in the diet.

    Hope this helps!

  30. Tammy says:

    And sadly, the “miracle” Apoquel, with the immune suppression effects, could be causing the yeast to overgrow because the dogs immune system is not functioning properly. I had my french bulldog on Apoquel for about a month and while it did initally stop the itching, she started getting an inflamed vulva and her ears began to itch. I had the miracle drug called Temaril p and had her on that for over 5 years, then she developed calcinosis cutis as a complication from iatragenic cushings syndrome. In taking her off the Temaril-p the itchy dog returned and Apoquel was the solution….until the issues began. I stopped the Apoquel and within literally 1 day, her inflamed vulva was no longer red and swollen and and she had stopped scratching her parts on the ground. It happened 2 times that I stopped the Apoquel so I am certain theis was caused BY the Apoquel…she also developed bloody diarrhea which I have seen as a rare side effect of Apoquel. So now I have her on Hydroxizine and she seems to be doing ok. Apoquel is such an unknown at this point and to mess with the immune system, I feel, is just asking for trouble down the road. Having an itchy dog is so draining for both dog and owner, so I understand the desperation you all feel. But having gone from one drug that caused my dog serious harm (Temaril) to another with more potential long term health risks….I am going to investigate Respit next as it seems the least likely do do any long term harm to my dog. I wish everyone success in getting their dogs less itchy.

  31. Tammy says:

    And I forgot to mention, that while my frenchie was on Apoquel she developed an unpleasant smell…she would get stinky a few days after a bath, whereas prior to Apoquel she could go for weeks before getting stinky. I think it was the immune suppresion causing bacteria and/or yeast getting out of hand on her skin and in her folds much quicker. It was a different smell that just, “stinky, needs a bath, dog smell”

  32. Jeff McLaughlin says:

    Seeing Tammy’s note make me want to reply. My experience with Apoquel has been very positive (5 years) with no ill side effects that me or my vet have seen. Although I understand the immune suppression aspects this has to be a better choice then steroids and monthly injections that we performed previously. My dog has a better life. Luckily he does not need the medication during the late fall/winter/early spring — he is just allergic to “summer”. I don’t think it is fair to condemn a medication because it did not work for you. Yes, by all means share your experience but one should not deter others from seeking a solution because you experience did not solve the problem.

  33. Tammy says:

    Hey Jeff, happy that you have used Apoquel for so long with no known issues. I did not condem using it generally, I refuse to use it for my dog because she showed signs of problems, things she did not have ever before using Apoquel. It does come down to quality of life and to that fact, I had my vet try Cytopoint of my girl 3 weeks ago and that IS working with minimal side effects that I can see visually. What is going on internally that may cause problems down the road, I won’t until it happens, IF it happens. I still do not like giving any of these drugs/immune-messing with compounds, as I have strive to raise them as naturally as I can. But of course I do not want her to be miserable and she was. I am running out of options….no steroids, no Apoquel, no Hydroxyzine….maybe Cytopoint is the one that helps her without killing her. My intention was not to deter, it was to show that it was not always harmless and vets often do not even inform owners of potential issues….so my intention was to encourage that people educate themselves, be very cognizant of possible problems and diligent in monitoring your dog while on these meds and to give details of what my dog experienced so that others could compare their experience. Happy your dog has better quality of life.

  34. L says:

    My dog receives allergen specific immunotherapy (desensitization) times five years with excellent results. It cost a few bucks but is the most natural treatment available, no drugs.
    See a veterinary dermatologist for intradermal skin testing and treatment options.
    That’s what we found worked best for my dog.
    There is no cure for environmental allergies but there is effective treatment.

  35. Joseph says:

    SLIT therapy is a good option for pet owners afraid to give injections or animals that are timid of the needle.

  36. TANYA says:

    I luckily came across this article just before sending a hair sample to Dr. Khalsa for the Allergy Elimination 4 pets. I was skeptical and this article confirmed it. We are just so desparate to help our pets.

    Our guy has been having a hard time for the past several years mainly with ear infections, itchy skin (malassezia) and sore, swollen and bleeding paws. We had him tested for allergies (blood test) and have a list of his allergens (food and environment), so we now know what he can and can’t eat. His ears seemed to have cleared up but his underbelly and paws are still bad. On the list of allergies there was another form attached where we could order a specialized injection that would help with his “highest” allergens, we will consider this option.

    After reading all these comments I have contacted a veterinary dermatologist to schedule an appointment (the closest to us is 8hrs away, but we will make the trip). Has anyone ever used Zymox shampoo to help with the yeast overgrowth (malassezia)? It was something recommended by Dr. Khalsa.

  37. Jessica Lobert says:

    Hey hey, I’m back four years later with an update to anyone who might find this thread. I requested some info on long term impacts of apoquel in my first comment but there really wasn’t any since it’d been out such a short time.

    Story time.

    I have a now 9-year-old purebred Amstaff, brindle and white (mostly brindle). I’ve had him since he was 1.5 years old (rehomed from a family member in March 2013). He had no skin issues as a pup. Then we move to Colorado and in Feb. 2015 bam, constant itching and misery. So I put him on Apoquel, this wonder drug! Until it wasn’t, and we found cancer (Keloidal Fibrosarcoma) growing on his side, had it removed, and then had more cancer show up in his groin (Hemangiosarcoma) approximately a year and a half later. Apoquel suppresses the immune system, and the vet suspected that it also suppressed his ability to fight off cancer cells.

    We take him off the Apoquel and put him on Cytopoint injections. They very quickly became pretty ineffective, and at $120 a shot, it was hard to justify four or five days of relief. The vet suggests we see a dermatologist.

    May 2019 off to the dermatologist. They test him for allergies and he is allergic to so much stuff they can’t even fit it all into his serum.

    September 2019 his misery has gotten to a point where he’s up all night itching and we can’t take it anymore – given low dose continuous steroids to help mitigate while we pray for the allergy injections to work.

    February 2020 he breaks out with a skin infection, we try taking him off the steroids but the infection gets worse. He has a massive shed during a bath and loses probably 40-50% of his coat, still there, but very thin. Dermatologist increases his baths and we put him back on the steroids.

    Late April 2020 still has some of the skin infection and we are discussing making changes to his allergy serum with the dermatologist because it’s not working and we are approaching the year mark, I bring up his thyroid… His T4 was tested by his regular vet in December and came back low but within range. Dermatologist takes a scraping of the infection and notices his hair is in almost a hibernative state, which can happen with low thyroid. She tests his thyroid, but this time she tests the T4 and the Thyroid Stimulating Hormone (TSH). It comes back just low enough to be on the fence, but I say “let’s do it.” He goes on Levothyroxine. Still on the allergy shots.

    June 2020 he’d just had his follow up. His levels are normal, we’d backed down his steroid dosage, his energy is up, and I don’t remember the times when his skin ever looked so clear (not red/pink). The dermatologist said she thought he just seemed brighter overall and is incredibly impressed.

    October 2020 – still on the immunotherapy allergy shots, still alternating 2.5mg prednisone every other day, 0.7 mg levothyroxine twice a day. He’s itchy on occasion but not nearly what he was and it’s much more manageable with weekly MiconaHex+Triz baths.

    TL:DR – It wasn’t just allergies, his thyroid was messed up and now I have a much happier pup on much less drugs.

  38. Harold says:

    Hello Skept Vet,

    Great article as well as comments. Are you planning to do any updates on C.A.D. therapies in the future? Any thoughts on the latest study of Respit? https://bmcvetres.biomedcentral.com/articles/10.1186/s12917-016-0917-z

    The study seems to show good results though not sure if there’s an issue with competing interests? Thanks!!

  39. Karen Arkin says:

    Hi there. Wondering if this information translates to cats at all. I’m in allergy hell with my almost 18 year old DSH cat, and am at a loss as to how to help him. Tried depo medrol injections which *seemed* to work when we lived in Napa Valley, but don’t work in Chicago, even with injections every month or two, and his liver values were getting really bad. Tried chlorpheniramine which, according to your dog chart, and my experience, is useless. Doc suggested his fur chewing might be pain related, so prescribed gabapentin, of course, which has also been useless.

  40. skeptvet says:

    Allergies are much less common in cats than dogs, so consequently there is less research evidence. In general, the same approaches are used: antihistamines, glucocorticoids, cyclosporin, hydrolyzed protein diets. Apoquel (Oclacitinib) has been a game0change in dogs, and there is hope it might help cats, but the only research out so far is basic safety studies, so you could talk to you dermatologist about trying it.

    Good luck!

  41. Karen Arkin says:

    Thank you for your reply. Not sure how I missed it until now. My vet suggested trying Apoquel on my dog, who seems to have seasonal allergies, mostly in spring. It’s not out of control but would like to make him more comfortable if I can. He has a history of what vet thinks is immune mediated neutropenia. It was a hellish 3 or so years of testing, overnight hospital stays, 106 degree fevers, steroids, stem to stern gutting to get biopsies, etc. Vet suggested he may outgrow it, and shockingly it seems like he did. His last dose of prednisone was a year ago and his neutrophils have been normal for probably 18 months. Should I be concerned about using Apoquel with his history? The cat I inquired about is still here. He was diagnosed with tumors in his liver 3 weeks after my inquiry, and goes through fur chewing phases, but I don’t think it’s allergies. He goes months at a time without chewing and interestingly famotidine seems to help. He gets mirtazapine, Cerenia, and famotidine every 3 days, subQ fluids every other day, and aside from being thin, he is doing surprisingly well.

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