Case Studies in Canine Dermatology


Q: Are commercially available fatty acid supplements (such as those purchased from human health food shops) comparable in efficacy to the specialist prescription diets you mentioned in the talk?

The commercial and fatty acid supplements available on the market are of variable efficacy. Those found in human health stores will not have conducted efficacy and safety studies in dogs and cats. For this reason, while adequate bioavailability and beneficial effects may occur as a consequence of supplementation, it cannot be quantified. Manufacturers of each of the FA supplements on the veterinary market will have their own data to support their product however direct inclusion in the diet not only makes the entire process more convenient for the owner but anecdotal evidence recently presented at dermatology meets (In: Annual Meeting of the American Academy of Veterinary Dermatology & American College of Veterinary Dermatology) suggest that ‘higher amounts’ may be delivered to the animal by this method (Roudebush 2001). This may be related to both the digestive process and also the greater compliance due to more reliable delivery via dietary methods.

Q: Does the Skin Care diet contain enough fatty acids that you do not need to supplement the animal as well, for example to support an atopic animal?

As detailed in our presentation, the Skin Care products have been trialled in the field on diagnosed Atopic dogs, precipitating impressive results with a highly significant 3x reduction in clinical CADESI score. So there is no need to supplement the fatty acid levels within the diet any further.

Q: Question for Catherine: please can you repeat the author of the study about fatty acids and its conflicting blends?

The publication is: Olivry T, Foster AP, Mueller RS et al. Interventions for atopic dermatitis in dogs: asystematic review of randomized controlled trials. Veterinary Dermatology 2010; 81: 143-146.Please note, this is a review discussing many different methods for the management of dogs with atopic dermatitis. The section discussing fatty acids makes up just a small part of it. You can view most Veterinary Dermatology articles for free online.

Q: Are royal canin looking at doing skin care diet for cats in the near future?

At present we know not of any plans to release a Feline Skin Care product. The Feline skin care market is developing however (as we’ll note in this week’s presentation) so we can only hope for the future!

Q: What are the advantages of the skin diet over the hypoallergenic diet which is also recommended for skin allergies as they both have similar dermal care properties?

The indications for using the Hypo and Skin Care products are similar in that they are both good options when dealing with dermatoses; both have an optimal level of highly digestible protein, both have the skin barrier complex which supports cutaneous ceramide production (Watson 2006)and both have supplemented omega-3’s (EPA and DHA). However the big difference between the two is that Skin Care contains a blend of fatty acids (particularly those from the linoleic acid andgamma-linolenic acid group) which we have demonstrated to be beneficial in our studies. This is why Skin Care is a good option for nutritional management in cases of atopy, FAD and pyoderma for example. Hypoallergenic, on the other hand incorporates hydrolysed proteins, so this diet is more geared towards food allergies and food elimination trials. Being hyper-digestible it has gastrointestinal benefits also, so a dog with combined skin and GI signs would do well on Hypoallergenic. Sensitivity Control backs up these diets as a secondary offering with select protein and carbohydrate sources (duck and tapioca in the canine dry and chicken or duck and rice in the canine wet formats). These are another option and are produced in the same ‘line-cleaned’ batches as Hypoallergenic to prevent stray protein sources from entering the food. However feeding Sensitivity Control as an elimination food is dependent upon a complete lack of previous exposure to its ingredients. (Watson AL, Fray TR, Bailey J et al. Dietary constituents are able to play beneficial role in canine epidermal barrier function. Experimental Dermatology 2006; 15: 74-81.)

Q: when to start with skin care / when with hypoallergenic or sensitivity control?


Q: What is the protein source of the Skin Care diet? Wheat gluten; found to be 99% digestible (RC internal data)

Q: which is the perfect omega 6 : omega 3 ratio for dogs and cats supplementation?

At Royal Canin our belief is that clinical studies are more valuable than relying on specific ratios of which fatty acids to supplement. This is because even published studies quote wide (and often very different) ranges of ratios as being optimal, so it is hard to know where the best ratio lies. Therefore, we feel clinical studies (which we have already performed and that I briefly detailed in the webinar) provide us with the information about our diets that we can most reliably trust, instead of relying on (at the moment) what seems to be inconsistencies in publications.

Q: Many of our clients use Evening Primrose Oil or Cod Liver Oil (human formations) in their dogs for healthy skin. Are the EFAs in these oils helpful in dogs and in the correct ratios?

The commercial and fatty acid supplements available on the market are likely to be of variable efficacy. Particularly those manufactured for human use will not have had efficacy and safety studies conducted in dogs. For this reason, we cannot make recommendations on these products because there are other highly effective options (such as the Skin Care diets) which have been demonstrated in the species in question and are nutrionally balanced for that species as well.



Q: How does James Wellbeloved fare as a hypoallergenic food trial?

To my mind there are 3 levels of diets which are currently marketed as ‘hypoallergenic’: 1)The naturally-sourced or named-protein products (such as James Wellbeloved) – they take their proteins from ingredients which aren’t normally associated with adverse reactions to food but are not manufactured to the same standards as elimination diets 2) The exclusively select (novel) protein diet such as Sensitivity Control which are manufactured with very stringent internal controls on production and quality assurance and 3) the truly hypoallergenic diet; these are produced more specifically for the purposes of elimination trials (with pre-digested proteins or ‘hydrolysates’).These are best suited to food elimination trials.

Q: Can feeding the dog’s ‘normal’ diet at the same time as a hypoallergenic diet (i.e. while transitioning from one to another) cause sensitisation to

We recommend immediate removal of a diet with allergenic properties without a transition period so concurrent feeding of a normal and hypoallergenic diet should not occur.

Q: you mention that food allergic dogs are often less than 6 months old -many of the hypo allergenic diets are unsuitable for young dogs – which diets can you recommend that avoid the ubiquitous poultry in such youngsters?

To be clear and re-iterate what we said in our webinar, Hypoallergenic is formulated such that it is fully complete and balanced for a growing puppy (and kitten). You can feed a young dog confidently with this product using the feeding guides found in our product books or available through our helpline. This way you can go one step beyond avoiding poultry, and feed a hydrolysate instead.

Q: are all hydrolysate diets effective?

Great question. The effectiveness of hydrolysate diets are very much dependent upon the individual animal and the quality of the hydrolysate in question. This is why it’s so difficult to paint all diets with the same (‘efficacious’ or ‘non-efficacious’) brush. The premise of a hydrolysate diet is to reduce (ideally completely eliminate) allergenicity such that the typical type-1 hypersensitivity reactions to food proteins don’t occur. Where this becomes a problem is where an animal displays an allergy which is NOT IgE-mediated (i.e. not type-1; a concept suggested but not yet explored in the veterinary world) or displays multiple allergies, sometimes to multiple proteins or very select amino acids which somehow make their way into the digestive tract. This is the very small population (5%of food adverse patients – Biourge et al 2003) of dogs that are refractory to currently available hydrolysed diets. Manufacturers such as Royal Canin are doing all they can to help these patients further by improving contaminant-controls (to reduce the incidence of ancillary proteins making their way into the food) and exploring the best protein sources to tackle adverse reactions. – What about the fact that there tends to be a wider span of protein sizes in some diets compared to others?

Q: if you suggest fish and potato for dogs, what would you suggest for cats as a homemade hypoallergenic diet?

My suggested answer: We would not suggest homemade diets for food elimination trials, unless trials with the commercially available diets had proved unsuccessful and a food allergy were still strongly suspected, in which case there is no other option. Good sources of protein for Feline elimination diets can include duck, goat, horse, pheasant, rabbit and even venison. Your owner should be guided by availability of these ingredients but more so by their cat’s dietary history. In order to be truly effective as an elimination diet the cat must not have had any prior dietary exposure to this ‘novel’ protein source. The owner should also be made aware that a homemade diet of this sort is unlikely to be nutritionally balanced.

Q: I have such a problem with food trials – the clients I have with pruritic animals can never afford to feed the hypoallergenic prescription diets -can you offer any suggestions?

I’d be sure the owner is completely aware of the value of an elimination trial (after all without a trial there is no confirmed diagnosis!) and then also the actual cost to feed (per day) a diet such as Hypoallergenic. In fact, feeding a 15kg dog from a 7kg bag, sold at our SSP, will only cost them around £1.53 per day if they’re feeding according to our guidelines. If they cut out all other food sources (chews, rewards, supplements..) they may even make a saving. Because diet isn’t perceived be as valuable as a ‘medicine’ it’s always going to be difficult… what I think we need to make owners aware of is that in the case of true food allergy, the food IS often the be all and end all of management of that dog or cat; if the owner can be consistent in their feeding, this is a MUCH better option than having to repeat-visit for symptomatic treatments for the rest of their dog’s life.

Q: What about gluten allergy?

Canine allergies to gluten are in fact rare. Apart from the breed idiosyncrasy we’ve seen in Irish Setters (the original line of affected individuals has now been bred out) literature supporting sensitivities in the general Canine population is difficult to come by. These proteins have been extensively investigated (and are often thought of negatively) due to their allergy-inducing abilities in humans. Wheat gluten is in fact an exceptional protein source as it’s highly concentrated (with protein), free of biogenic amines (histamine for example) and has a low fibre level meaning it’s highly digestible (99%). This is why we use wheat gluten in our Skin Care product. It’s also high in glutamine (important in maintaining digestive integrity and supplemented in human gastro-enteral cases) and relatively available and sustainable.. So watch this protein source! Having said all of the above, if an animal is confirmed gluten-sensitive (by means of not only serological tests but a dietary challenge) then a hydrolysed protein diet such as Hypoallergenic is currently our 1st choice in

Recommendation. Hall, E.J. (2004) Breed specific intestinal disease, In Waltham Focus, 15(2) pp36-


Q: How long does it take for a dog to become food allergic if it’s been on the same diet for 2.5 years and then starts to have skin lesions as you described in your first food allergic slide?

Seeing as a true food allergy is dependent upon the affected individual going through a period of sensitisation whereby the immune system is being ‘primed’ to react to that unique dietary allergen it’s almost impossible to put a definite figure on how long it takes for the clinical signs of an allergy to kick in. Texts I’ve read have mentioned allergies developing after as short a feeding period as 2months through to 3 years… very frustrating obviously when an owner insists that ‘everything was completely fine and consistent until now’. In a slow-developing allergy we’ll still have to change the diet.

Q: what is the difference between food allergy and food intolerance? Some of the subtleties in these terms are dependent on the source of your information.

From my reading I see it as thus: Food allergies, food intolerance and food intoxications are all part of the larger ADVERSE FOOD REACTION (AFR) group. An intolerance is a lot more common than an allergy and entails metabolic, pharmacologic and idiosyncratic reactions to ingesta (for example enzyme deficiencies, histamine consumption in spoiled fish and gluten-enteropathies in Irish Setters respectively). True food allergies are the ones that involve the immune system, are unique to the individual and entail a period of sensitisation (much the same as a reaction to a vaccine) during which time the animal develops an unhealthy bodily reaction to an allergen. The vast majority of these are proposed to be type 1 (IgE-mediated) hypersensitivity reactions however type III and I have also been proposed. An intolerance case will need a low-residue highly digestible diet, an allergic one will need one that avoids the offending allergen at all costs. There is still a lot we can learn in the area of small animal AFRs and only further investigation will disclose exactly what is happening in our truly ‘food allergic’ cases, however clinical signs and our approach to management are usually consistent across the entire AFR group; identification and avoidance of the offending foodstuff is key.

Case Studies in Feline Dermatology


Q: Do you have a diet that helps with improved coat condition in cats that get matted easily, esp. Persians?

For long-haired cats that are prone to matting, we would always advise regular grooming, as very often this will be the most effective way of keeping the matting under control. It is also important to consider obesity, arthritis and other causes of joint pain in a cat that used to be able to keep its coat in good condition but now fails to do so, as very often a problem resulting in painful and or reduced mobility for the cat can also result in reduced grooming, particularly if it becomes too painful for the cat to groom itself as it did before. However, if the matting is purely linked to the fact the cat has a long coat, we would advise regular grooming coupled with a diet targeted at optimising the health of the skin and coat. Diets from Royal Canin developed for long-haired cats include the Feline Neutered Skin Diets as discussed in the webinar but in this case (a Persian cat) you could also consider using the Persian diet from our Feline Breed Nutrition range (also available to order through your Royal Canin Veterinary Business Manager).

Q: what sort of dose do you recommend of essential fatty acids in cats ?

Even published studies quote wide (and often very different) doses, ratios and combinations of fatty acids for use in cats and dogs with skin disease. Therefore, we believe that running studies on our diets, which we carry out before we launch a diet, to ensure we see changes in the skin condition of that animal on the dose/combination of fatty acid(s) used in that diet, is the most reliable way of ensuring the dog or cat is receiving the appropriate nutrition, rather than relying on a specific dose when the available science cannot yet reliably inform us of what is optimal.



Q: Advice please for feeding these in multicat households. Not feasible to seperate long term

Unfortunately, in multicat households, the only options for feeding include: a) feeding all cats the same diet; b) feeding all cats separately under supervision at set times or; c) separating the cats long-term so they cannot access each other’s feeding stations. However, Hypoallergenic is a very versatile diet and it may be that the owner chooses to feed this diets to all the cats in question(depending on their individual needs), which, although may not be the most cost effective option, is obviously a very convenient one. A less ideal option is to try and separate the cats as best as possible, accept that some cross-feeding may occur, and choose to deal with the symptoms of the affected cat when this does occur. However, this is never something we would recommend and the owner would have to be warned of the consequences of potential re-flares in their cat’s condition if they chose to follow this sub-optimal route.

Q: How can you be sure of the effect of your food trial in a cat that goes outside?

You can never be 100% sure of the effect of any food elimination trial in a cat that goes outside. That is why we would always recommend keeping a cat inside for the period of the food elimination trial if it is at all possible, as was detailed in the webinar. However, if an owner is adamant that they cannot keep their cat inside, we would advise taking the measures as recommended in Catherine’s presentation in the webinar e.g. bells on quick release collars to prevent hunting and advising owners to visit neighbours and dispense flyers advising local residents not to feed the cat in question (with photos of the cat). Tags can also be made to put on the cat’s collar asking local residents not to feed it.

Q: How good is serology to detect food hypersensitivity in cats?

Serology is a poor method of detecting food allergy in cats and dogs. Key opinion leader recommendation remains that the Gold Standard method for detecting food allergy in dogs and cats is only through the use of a food elimination trial, with re-challenge one protein source at a time following stabilisation, to identify the offending dietary allergen. Serology should not be relied upon.

Q: is it likely that cats will be allergic to the rodents and birds that they normally hunt and catch

It is unlikely but not impossible. The most common dietary allergens in cats include protein sources such as: fish, milk, beef and lamb. To be sure a food elimination trial is being carried out in the most effective manner possible, we need to ensure the cat in question is only consuming the diet the vet has advised and water, with nothing else: can the hypoallergenic diet be fed to kittens and lactating queens Yes, Hypoallergenic can be fed to lactating queens and we would advise that they are allowed to adlib feed, as would be recommended with any diet used throughout lactation. Hypoallergenic can also be fed to growing kittens if they need a hydrolysed protein diet. The feeding guidelines for growth are available in the most recent versions of the Royal Canin product books, available from your Royal Canin Veterinary Business Manager.

L.Danks, C.Howard & G.Stuttard authors. Copywrite Royal Canin SAS 2011

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