Here’s a citation for one of several technical articles I’ve been plugging through:
Thierry, Oliver, Douglas J. DeBoer, et. al. “Treatment of canine atopic dermatitis: 2010 clinical practice guidelines from the International Task Force on Canine Atopic Dermatitis. Veterinary Dermatology 21 (23 April 2010): 233-248.
This, and several other articles from Thierry (North Carolina State University) and DeBoer (University of Wisconsin – Madison) have been extremely helpful in shedding some light on the state of the field, though I’m only observing from a layman’s point of view.
I have a lot of scattered thoughts from reading their publications.
First of all, I’m thrilled that there is such a thing as an International Task Force on Canine Atopic Dermatitis, founded in 2009. This particular article is co-authored by veterinary experts from the USA (the two authors names I listed above), as well as Switzerland, Scotland, Germany, and France. Other members of the task force come from the UK, New Zealand, Australia, the Netherlands, and Japan.
From what I’ve gathered, such a group was a long time coming, and desperately needed to help bring some organization and consistency to the information collected from research and experimental trials and clinical application. The current state of the field is still riddled with huge holes and and unknowns, despite the prevalence and even increasing frequency of canine skin problems.
The abstract reads quite straightforwardly:
Atopic dermatitis (AD) is a common chronic relapsing pruritic skin disease of dogs for which treatment has varied over time and geographical location. Recent high quality randomized controlled trials and systematic reviews have established which drugs are likely to offer consistent benefit. The International Task Force for Canine AD currently recommends a multi-faceted approach to treat dogs with AD. Acute flares should be treated with a combination of nonirritating baths and topical glucocorticoids, once an attempt has been made to identify and remove the suspected causes of the flare. Oral glucocorticoids and antimicrobial therapy must be added when needed. In dogs with chronic AD, a combination of interventions should be considered. Again, factors that trigger flares of AD must be identified and, if possible, avoided. Currently recognized flare factors include food, flea and environmental allergens, Staphylococcus bacteria and Malassezia yeast. Skin and coat hygiene and care must be improved by bathing with nonirritating shampoos and dietary supplementation with essential fatty acids. The severity of pruritus and skin lesions can be reduced with a combination of anti-inflammatory drugs. Currently, medications with good evidence of high efficacy include topical and oral glucocorticoids, and calcineurin inhibitors such as oral ciclosporin and topical tacrolimus. The dose and frequency of administration of these drugs should be tailored to each patient considering each drug’s efficacy, adverse effects and cost. Allergen-specific immunotherapy should be offered, whenever feasible, in an attempt to prevent recurrence of clinical signs upon further exposure to environmental allergens to which the patient is hypersensitive.
An abstract, of course, is only an extremely condensed presentation of the information contained within. Once I actually waded through the article, I felt like I got a better sense of what was going on.
Their definition of canine atopic dermatitis: “a genetically-predisposed inflammatory and pruritic skin disease characteristic clinical features that is associated with IgE antibodies, most commonly directed against environmental allergens” (234). The genetic predisposition of CAD leads me to think that breed knowledge may be useful in understanding how to remedy particular situations. Examples pictured in this study include a West Highland White Terrier and an English Bull Terrier, breeds which I understand to be constantly plagued by skin problems. I doubt it’s feasible to churn out multiple breed-specific reports, but this underscores the point that knowing a breed, and being aware of all the possible health problems associated with the breed, is necessary to breeders, pet owners, and veterinary health advocates alike.
I find it interesting to note the emphasis on environmental allergens; food allergies are apparently treated as separate issue, with different diagnostic procedures. Nevertheless, there is some interrelation: “The International Task Force on Canine Atopic Dermatitis supports the concept that that cutaneous adverse food reactions (food allergies) might manifest as atopic dermatitis in some canine patient, or in other words, that food components might trigger flares of atopic dermatitis in dogs hypersensitive to such allergens” (236). I read at least one other article from the group [citation pending] that made the point that dietary changes and nutrition can play a role in improving the symptoms of CAD but food hasn’t been adequately considered or studied (and so with no scientific data to go on, vets generally don’t make these kinds of recommendations).
In my own experience, my vets were quick to rule out food allergies, dismissive of my changes in diet, and uninformative (or NON-informative, as in they just didn’t have any information to offer) about ingestible remedies aside from prescription drugs. I am not seeing a holistic vet [YET!], but as per my previous review, I am somewhat irate that one has to go to an explicitly branded “HOLISTIC” vet in order to obtain this kind of information at all.
The article talk about fatty acid supplements, but only in supplemental form. More on that later.
The article then goes on to list and evaluate the overall efficacy of various standard recommendations:
Identify and avoid flare factors. In order to start fixing things, you’ve got to be able to say with some degree of certainty what the problem is in the first place! If you know the problem is bacterial or fungal, then go with antimicrobial therapy (bacteria or fungus killers).
Improve skin and coat hygiene and care. You can bathe with nonirritating shampoos. This is basically common sense, and so there probably hasn’t been a sense of urgency in conducting clinical studies. The article is conservative with its conclusions on the efficacy of shampoos. “There is currently no evidence of any benefit from using other shampoos or conditioners containing ingredients such as oatmeal, pramoxine, antihistamine, lipids or glucosteroids… Taken as a whole, these findings suggest that the benefit from bathing might lie primarily with the action of washing the pet” (237).
You can also consider “pharmacological agents,” or drugs, to help boost skin care. Their recommendations of glucocorticoids (steroids) are ideally for short term use. With topical lotions, “caution is advised with long-term use, as adverse effects are likely to occur. These usually include skin thinning with or without tearing, comedones and superficial follicular cysts (milia)” (237). With oral glucocorticoids, such as the Temaril-P that Bowdu got, you may prolong use as long as the dog responds with a degree of quick and noticeable satisfaction, but everything about the paragraph makes it sound like it’s really not a preferred option, though it doesn’t come right out and say what long-term negative effects are (or even how they define “prolonged use”). It’s not a measure of desperation, but basically, if I can read a tone into this dry, scientific writing at all, it sounds like it’s saying if ANYTHING else works better, PLEASE go with another option. “Because most dogs with AD have signs that respond to oral glucocorticoids, failure of rapid clinical benefit with this category of drug should prompt the clinician to reconsider alternative diagnoses or the presence of secondary complications (for example, skin infections, ectoparasitism, or other nonatopic food reactions)” (238).
If the condition is already acute (and the article contains some wince-worthy pictures of what counts as “acute” dermatitis — Bowdu is doing quite well in comparison), things that are NOT really going to improve the condition include antihistamines, fatty acid supplements, tacrolimus ointments (Protopic, used a lot in Japan) or cyclosporin (Atopica). These things, however, are more beneficial in long-term skin management. Antihistamines, for example, may provide some relief if you can start dosing just before your dog becomes symptomatic, so you can block those buggy little histamine receptors before the allergens actually appear. This requires knowing when allergy season hits in your neighborhood — something we’ve barely gotten a handle on after the fourth year of living here.
More on long-term, chronic treatments…
Identify and avoid flare factors. Again. If the itching is not just seasonal, elimination diets are recommended to rule out food allergies. I’ve looked at some material on this, and it really sounds hard, so hard… especially with Bowdu, and our neighborhood, and all the nasty edible litter on the streets that our dogs frequently ingest (midnight sidewalk chicken bones — Bowdu’s favorite!). “Even if an attempt at controlling diets was made early in the course of the disease, this aspect might have to be reconsidered in case of disease flares, especially if anti-inflammatory therapy is not or no longer effective. Indeed, atopic dogs often acquire new hypersensitivities, and the development of a novel food allergy could be the cause of AD exacerbation” (239). Does this explain Bowdu’s rather extreme reaction to my recent offerings of beef, though he’s had cooked beef before with no problem?
This statement is also interesting: “At this time, however, there is no clear evidence of a superior benefit of hydrolysate-based compared to nonhydrolysed commercial diets, or of homemade over commercial diets” (239). I don’t quite understand what a “hydrolyzed protein” is yet, but I take it as processed kibble that is meant to be more easily consumed by dogs with protein allergies. This statement is footnoted with this citation, which I will have to follow up on:
Olivry T., Bizikova P. A systematic review of the evidence of reduced allergenicity and clinical benefit of food hydrolysates in dogs with cutaneous adverse food reactions. Veterinary Dermatology 2010; 21: 31-40.
What I take this statement to mean is not that raw or home-cooked diets don’t work, but that there haven’t been enough studies done for them to make a scientifically responsible statement as to their benefits. This was more or less noted in the introduction of the article: “Insufficient evidence for recommending an intervention does not mean that the drug or product is not effective, but simply that there are no studies documenting their efficacy or lack thereof” (234).
Use an effective flea control regimen. Year-round flea adulticides might be necessary. A single bite could set them off, as itchy dogs just become VERY itchy to everything.
Try allergy testing. Options include allergen-specific intradermal tests (IDT, the kind where they inject toxins directly into your dog’s skin and observe the results) or IgE serological tests (like VARL Liquid Gold, I guess). You’ve gotta do this if you want to proceed with allergen-specific immunotherapy, where the vet injects your dog with small doses of the specific allergens he’s most vulnerable to and slowly condition his immune system over time.
This statement is interesting: “It must be remembered, however, that positive immediate IDT reactions and IgE serologies to environmental allergens are also common in dogs without signs of AD… As a result, these tests cannot be used to differentiate dogs with AD from normal dogs. Importantly, there is no evidence that serological and intradermal tests to determine hypersensitivity to food allergens reliably predict the results of restriction to provocation dietary trials in dogs with adverse food reactions… Consequently, such tests cannot be recommended to assess the presence of food hypersensitivity in dogs with food-induced AD” (239). I find this noteworthy, because those who have reported back on allergen-specific tests have seemed so grateful to be able to list specific foods that their dog is allergic to. I would be too, because at least these are dietary ingredients that I know I can control. What I’m reading here, however, confuses my understanding of the clarity of these tests. Italso makes me wonder about discrepancies between what is tested and what is actually ingested by our dogs. If, for example, they say the dog exhibits an allergic reaction to “chicken,” are they talking about the chicken and parts that are ground up and processed into kibble, or are they talking about raw meat pulled from a freshly-slaughtered, organically-fed, cage-free backyard hen? What is going on in the lab environment vs. the real world that accounts for these inconsistencies and false positives?
Get rid of dust mites in your house. Since these are the most common allergens to be found in dogs with AD, a clean house probably helps. A very true sentence from the article summarizes my dilemma: “Reducing mites and their allergens in the home of a patient with mite sensitivity is seductive in theory, but difficult in practice” (239). To say the least. Sometimes I feel like I sweep this house and wipe down the counter so often, I’m at risk for some kind of obsessive compulsive disorder myself! I love a clean house, but I do not have the time to keep it clean enough to have any long-term effect, and I am not hiring a maid. File this recommendation under “Dream on…”
Improve skin and coat hygiene and care, over the long term. This is where dietary supplements come into play. Most surprising to me, they talk specifically not about Omega-3s, but Omega-6s. “In normal dogs, dietary supplementation with EFA [Essential Fatty Acid], or the feeding of EFA-rich diets (especially those rich in the omega-6 EFA linoleic acid) usually results in improvement in coat quality and gloss with an associated reduction in transepidermal water loss” (240). Currently, Bowdu gets some linoleic acid in egg yolk and olive oil, but not very much. Oils rich in linoleic acid include safflower, sunflower, flaxseed, and hemp — the latter two of which I’ve used on a trial basis. I guess this is worth reintegrating after all.
As for food, they list Hill’s Science Diet Canine d/d Salmon & Rice (prescription only) as an effective product based on randomized clinical trials. However, you can check out the ingredients for yourself on the Hills website, and come to your own conclusions. I doubt that other high quality, commercially available fish-based kibbles were tested in the cited study, if Hill’s Science Diet was the only one deemed worthy of mention. I wonder if the problem is that they only looked at prescription kibble? From what I’ve seen, there’s already some kind of oligopoly on that market in the US veterinary system; there are biases inherent to the study, if they limited their sample to what was available at the vet. I have to follow up and read the report, but the citation is as follows:
Glos K., Linek M, Loewenstein C. et. al. The efficacy of commercially available veterinary diets recommended for dogs with atopic dermatitis. Veterinary Dermatology 2008: 19, 280-7.
[EDIT 21 August 2010: 50 dogs total were tested on Hill's prescription salmon & rice, Eukanaba Dermatosis, Royal Canin Hypoallergenic, and the control group ate Pedigree Maxi Chicken & Rice. 43 dogs finished the trial. When you divide that up by four, there just aren't that many dogs eating each of these foods, and there's still a lot of wiggle room for error, given environmental factors and breeds and concurrent use of other allergy regimens that the dogs continued while on trial. And the study was sponsored by Procter & Gamble. This last bit isn't much of a secret -- most of the scientifically rigorous, publishable studies on dog food are sponsored by a major corporate pet food company. I'll be surprised when I see a "serious" study pitting, say, 25 dogs on Pedigree vs. 25 dogs on a raw diet, sponsored by Royal Canin.]
To my mind, this almost discredits what the report has to say on the matter of food altogether, and I’m inclined to doubt that they seriously considered the matter of nutrition at all. At least not here. Perhaps they felt food was beyond the scope of this article, as well as other topics I would have liked to see explored like the advising clinicians to consider the relationship between AD and other immune disorders (like hypothyroidism), or taking breed-specific trends and breed histories into account. But in a way, I think the kind of specialization represented by the International Task Force on Canine Atopic Dermatitis also reflects the organization of current veterinary practice that is in some ways inimical to more holistic approaches or remedies that aim to treat overall health, not just compartmentalized symptoms. None of their recommendations seem particularly bold, just an update on some already-common practices. The article does take care to stress a multifaceted approach undertaken in accordance with patient wishes, and it does highlight the need for more information. Unfortunately, I don’t see enough in the article that really presses at why current remedies remain so ineffective, and to propose radical new changes to clinical practice that could generate new solutions to these increasing problems. Maybe that’s to be found in a different kind of article, if not a different kind of practice altogether.