Environmental Allergies in Dogs – Canine Atopic Dermatitis

An Introduction to Atopy in Dogs

Allergies are probably one of the most frustrating things to deal with as a pet parent – seeing your pup being constantly uncomfortable, itching and scratching – can be really hard to see. The good thing is that though allergies are not curable, they can be manageable.

So today what I am going to walk you through is the clinical signs, diagnostic process and the management strategies that can be options for dog’s with environmental allergies. And what you should know as a pet parent with an itchy dog.

AN INTRODUCTION TO ENVIRONMENTAL ALLERGIES IN DOGS:

During your dog’s examination your veterinarian will probably ask you a lot of different questions about your pup and their health history, along with what they are eating or have eaten in the past. What medications your dog is on – and MORE.

All of these answers in combination with lab testing and clinical signs will lead them towards a diagnosis. The reason why all of these factors need to be considered when making a diagnosis of environmental allergies is because there is no singular test that can tell you if a pet has environmental allergies.

Thus the diagnostic process is more a process of ruling other conditions out, than confirming a diagnosis (this is called a diagnosis of exclusion).

CLINICAL SIGNS OF ATOPIC DERMATITIS IN DOGS:

  • Seasonal or Non-seasonal itching: the most common areas involved are usually the paws, lower legs, abdomen, around the eyes, around the mouth, and around the rectum.
  • Chronic ear infections
  • Watery or Redness to the eyes
  • Sneezing
Most common areas a dog will itch with atopic dermatits - paws, lower legs, abdomen, eyes, mouth and rectum.

BREED PREDISPOSITION:

It is believed that allergies have a genetic component – however there is no research that has identified a particular genetic marker or breed of dog that more “prone” to allergies than another – allergies can happen to any breed of dog. That being said – on an observational basis veterinarians do tend to see more cases of allergies associated with certain breeds. Due to the possible genetic component of allergies specialist recommend that if a dog develops atopic dermatitis the dog no longer be bred. Breeds that we observe more cases of environmental allergies than others are:

  • Shar-Peis
  • Fox Terriers
  • Golden Retrievers
  • Dalmatians
  • Boxers
  • Boston Terriers
  • Labrador Retrievers
  • Lhasa Apsos
  • Scottish Terriers
  • Shih Tzus
  • West Highland Terriers

PRESENTATION:

Unlike food allergies where age of onset can be between 4m to 12 yrs of age, atopic dermatitis in dogs is usually seen earlier in life – between 1 to 3 yrs of age. This is not to say there aren’t dogs that develop allergies older than that – just that first signs of these allergies typically happen younger, rather than older. As the dogs get older owner clinical signs may become more severe, or the dog may accumulate additional allergies.

QUESTIONS YOUR VETERINARIAN WILL WANT TO KNOW:

Part of the allergy diagnostic process is going to be getting an in-depth look at your pup physically, but also looking at patterns over time. Your veterinary team will want to know the answers to many different questions when you bring your pup into their examination, and these answers will help them with recommending additional testing, and guide them to rule out other conditions.

I find for owners of pet’s with chronic conditions (like allergies) that keeping a log of when things have occurred is extremely helpful – not only to you- but your veterinary team. These logs allow for better communication, and may shed light on items that have changed, or general trends over time.

If you have any itchy pet here are some items I think are important to keep track of:

  • When did the itching start?
  • Is the itching all day long, or at certain times of the day?
  • Does the itching come and go with the seasons or is it year-round?
  • Where does your pup itch?
  • Did the lesion happen first, or did the itch happen first?
  • Did you change your pup’s food?
  • Did you change your pup’s bedding/bed?
  • Did you use a different cleaning product in your home?
  • Did you use a different scent product – like a candle, essential oil, or plant new plants in or around the home?
  • Did you go somewhere new – the beach, a trial, or go on a trip?
  • Are all your pets itchy within the home (if you have multiple pets)?
  • Are any humans in the home itchy as well?
  • How did the itching start, and how has it changed over time?
  • What therapies – supplement or medication have you tried in the past? How did your dog respond to those therapies?

DIAGNOSTIC PROCESS:

As I alluded to earlier – atopic dermatitis is largely based on clinicals signs, presentation and the ruling out of other medical conditions. Let’s talk a bit about the different conditions that you veterinarian will need to rule-out, and what the general process may look like.

EXTERNAL PARASITES

Sarcoptic Manage

This is a biggie – fleas and mites are very easily confused with atopic dermatitis as they can cause similar clinical signs. And though you can use a flea comb to try to observe fleas, it is actually fairly hard to do so, almost like finding a needle in a haystack. Fleas are TINY, and unless you have a hairless dog breed, your dog is covered in hair. It’s said that if you find just 1 flea, you can bet there are at least a hundred on your pup. And fleas only make up 10% of the flea problem.

Going beyond fleas itching can also be caused by mites – and mites are microscopic! Depending on the type of mite you may need to do either a cytology or a skin scraping in order to actually see them – and even then – just like fleas, there is a lot of real estate for them to take up residence.

Oftentimes this means that your veterinarian may recommend you place your pup on flea control or do a treatment of anti-parasitic medication in order to completely rule out these parasites. However this will depend on your dog and your situation.

HYPOTHYROIDISM

One of the major issues with hypothyroidism in dogs is that it can weaken the skin barrier. This weakness can make it difficult for the skin to function normally because it is unable to repair itself at a normal rate. This weakness can be then exploited by the environment – basically causing inflammation and itching.

In order to rule-out hypothyroidism your veterinarian may run a screening test called a T4. This test will give your vet a general idea as to the function and health of your pup’s thyroid gland.

VITAMIN/MINERAL DEFICIENCIES

Skin irritation and hair loss due to nutritional deficiencies.

There are many different types of vitamins and mineral deficiencies that can CAUSE weaknesses to the skin barrier. And though there are some hair tests and blood tests can give some information about possible deficiencies, these can be both inaccurate, or only recognize severe deficiencies (and miss smaller deficiencies that could cause issues). Usually these deficiencies are found with dietary evaluation by a board certified veterinary nutritionist coupled with clinical signs.

Some vitamin/mineral deficiencies can also be secondary to digestibility issues due to other diseases and conditions – such as irritable bowel disease (IBD), chronic gastroenteritis or pancreatitis. These conditions may require further testing in order to diagnose – for some conditions like pancreatitis a blood test called a cPL may be run, however for diseases such as IBD diagnosis is actually based on a biopsy of the gastrointestinal tract. These conditions may or may not need to be worked up with a specialist – such as a board certified internal medicine specialist.

FOOD ALLERGIES

The clinical signs of both food and environmental allergies can actually be exactly the same. It’s also possible to have a dog with both food AND environmental allergies. Which can make the diagnostic process fairly complicated.

If you want to learn more about food allergies, how they are diagnosed – you can read about it further in this blog post – but the basics that you need to know is that your veterinarian may place your pup on a food elimination trial in order to rule-out food allergies before moving forward with an environmental allergy diagnosis.

ATOPIC DERMATITIS

Once your veterinarian has ruled out other conditions – then they may use further tools in order to help solidify their diagnosis. They may look at how your pup responds to certain medications like steroids or apoquel – positive responses to these medications can further confirm an atopic dermatitis diagnosis in a dog. But overall once the diagnosis is solidified you can more forward with discussions on management strategies.

ATOPIC DERMATITIS MANAGEMENT STRATEGIES:

I view management strategies as having three main pillars. The first is the lower the allergen load, the second is diet and supplements, and the third is medications. Depending on the dog, your lifestyle as a pup parent, and other factors – some management strategies may be more effective or easier to do than others.

LOWERING THE ALLERGEN LOAD

If you think about it – most dogs don’t take a bath very often – they usually run around with the dirt and grime from days of adventures. But if you have a dog with environmental allergies – where dirt, plants, and dander is an issue, getting into a regular routine of removing said allergens is important.

This comes in a couple different forms, but probably the easiest of which is to just wipe your pup down – head to toes – each night with water. This “quick rinse” is a great option for dogs who may have gone for a quick walk around the block on mostly pavement. However for some dogs, this quick wipe-down will not be enough..

The second option is frequent bathes. Now it used to be the case that bathing you pup more often could cause harm to your pup. But now, with new inventions in bathing products there are now shampoos and rinses that are developed for frequent use. These products are often sold at veterinary hospitals, and your veterinarian can help guide you as to which product would be most appropriate for your pup.

But if you are looking for something over-the-counter – go MILD – I prefer fragrance free, without added essential oils – because some oils can be extremely irritating to skin, especially if the skin barrier is unhealthy. You especially want to avoid products with tea tree, lavender, or peppermint – all three can cause serious inflammation to pets with skin conditions.

Dog getting a bath and dog taking a walk on cement rather than the grass.
To reduce allergens you can either frequently wash/wipe away them from your pup, or you can avoid the allergens. Ideally doing both will give the best results.

The third option to reduce the allergen load is to avoid the allergen. You may note that your pup’s skin gets worse after certain activities, or maybe after going to certain areas. If that’s the case finding a way to not go to that place is ideal. Now I am not saying to never take your pup outside, or not allow your pup to have fun just because of their allergies. But if say your pup would be just as happy at a dog park on a grassy area, than at a beach – and your pup always has a skin reaction after going to the beach – maybe consider going to the beach less often (or not at all!) in order to avoid the inflammation.

Now it’s not always possible to avoid allergens (because of multiple reasons). So I implore you to look at these options and see which would be best for you and your pup, and know that you do have other options as well.

DIETARY CHANGE AND SUPPLEMENTS

OMEGA 3s

Omega 3s are probably the best-researched supplement for the management of environmental allergies in dogs. In this case I am speaking specifically about fish oils and fish based diets – as the dosage required to manage allergies would be near-impossible to obtain with Flax Seeds and relying on ALA to EPA/DHA conversion.

Now you should know that research has given fish oils about a 50/50 shot at improving your allergic pup’s symptoms, and some dogs should not be on fish oils as they can cause anemia at higher doses. So please speak to your veterinarian prior to adding on any supplements to your pup’s diet. And if you plan on giving fish oil long-term speak to your veterinarian about vitamin E supplementation, as chronic long-term fish oil supplementation can cause vitamin E deficiencies.

When choosing a fish based diet you will want to contact the company directly in order to get the amount of EPA or DHA per cup or kg of food. Then you can either calculate the amount of EPA and DHA your pup is getting per day, or you can take this information to your veterinary team and they can do the calculation for you. The reason why this is important is that you will need to know the dose of fish oils your pup is getting in their food, then use that to calculate how much additional oil your pup will need in order to get into therapeutic range. If a company cannot give you the EPA and DHA values, do not feed that food, find another company that can give you that information.

When choosing a fish oil for therapeutic purposes like for environmental allergies you will want to keep an eye out for products with a high EPA to DHA value, this is because EPA is the component that has that anti-inflammatory properties you need in order to help your allergic pup.

The following brands are ones that have great EPA to DHA ratios and that I have personally used to control environmental allergies in my dog Ranger:

The links above are amazon affiliate links, and if used I will receive a small commission on purchase at no additional cost to you.

ANTIOXIDANTS and VITAMINS

Another option in order to help with the inflammation and oxidative stress associated with environmental allergies in the addition of antioxidants to your pup’s diet. These supplements can be added into a diet in the form of whole foods or as separate supplementation.

Keep in mind that any whole food additions should be kept to less than 10% of your pup’s overall diet UNLESS it is incorporated into your pet’s complete and balanced diet.

If you do plan to add these to the diet via separate supplementation I highly recommend working with your veterinarian or a board certified veterinary nutritionist in order to obtain the proper dosing – as it will be variable depending on your pup’s overall diet composition.

  • Vitamin E: support cell membrane function and skin health

Whole Food Sources of Vitamin E: sunflower seed oil, wheat germ oil, safflower seed oil, beet greens, pumpkin and red bell pepper.

  • Vitamin C: helps convert free radical vitamin E back to vitamin E

Whole Food Sources of Vitamin C: tomatoes, sweet potatoes, red/green bell peppers, kiwifruit, broccoli, strawberries, brussel sprouts, and cantaloupe.

  • Quercetin: has been shown (in vitro) to prevent histamine release within the cell

Whole Food Sources of Quercetin: apples, berries, broccoli

PROBIOTICS

Did you know that between 70-80% of your dog’s immune system lives in their gut? A healthy immune system plays a huge role in how a dog will respond to different diseases or conditions. There are actually research studies looking at the microbiome of dog’s who have allergies, and they have found that in the case of both food and environmental allergies – dogs will have a less diverse microbiome in comparison to a healthy dog.

This suggests that the addition of probiotics to balance out the microbiome could be beneficial to dogs with the condition. It may help with nutrient absorption and the skin-barrier repair process as well. However as research related to microbiomes is still very much in it’s infancy at this stage there are no studies looking at probiotic supplementation and how it can affect dogs with allergies.

I personally have used both of these products for my pups at various times in their lives. I prefer the Proviable DC because it has several strains of helpful bacteria over the Flortiflora, which only has one. Another option is the Just Food for Dogs Probiotic (you purchase on their website or in select Petco locations) – which has a similar distribution of probiotic bacteria to the Proviable, however I still prefer the Proviable because of the individual blister packs which would maintain freshness of the product better.

The links above are amazon affiliate links, and if used I will receive a small commission on purchase at no additional cost to you.

PRESCRIPTION DIETS

The final non-medical option for dogs with environmental allergies is a prescription diet. There are many different types and brands of prescription diets on the market. And of course there is always the option of working with a board certified veterinary nutritionist to formulate a custom diet for your pup and their individual needs. You can find more information about homemade diets and how to go about finding a specialist in my blog post on this topic.

But basically prescription diets will contain multiple supplements and whole foods that combine to serve a particular function – in this case to help with environmental allergies. Here are some of the options currently available on the market.

  • Hill’s j/d: this diet is actually formulated for joints however it contains a very high amount of omega 3 fatty acids, vitamin e, and other antioxidants. So though this diet is not fish-based it does actually fall well within the therapeutic range for skin conditions.
  • Hill’s Derm Defense: this diet was formulated for environmental allergies and contains antioxidants, phytonutrients, and omega 3s to help support healthy skin and coat.
  • Purina Pro Plan DRM: this diet is formulated for environmental allergies by adding in additional omega 3 fatty acids, along with vitamins in order to support a healthy skin and coat.
  • Royal Canin Skin Support: This diet is formulated with additional Omega 3s along with a proprietary antioxidant complex to help support skin health and repair.
  • Just Food For Dogs Derm Support Fish: This is a fresh food diet (gently cooked) that is made with limited ingredients – salmon, cod, sweet potatoes, tapioca, flaxseed oil, sunflower oil, vitamins & minerals. Most of the omega 3s come directly from the fish within the diet, which is balanced out with seed-based oils to provide other essential fatty acids along with vitamin E.

MEDICATIONS

There are many different options as far as ways to help manage your pup’s allergies, once of which is using medications. Depending on the therapy used there may be certain monitoring to additional testing that needs to be done. Some of these may be short-term or long-term strategies, and it really depends on your dog and their situation as to which medication or therapy would be most appropriate for your pup. So please speak with your veterinarian when discussing these options to find out which are, or are not appropriate.

Immunotherapy

Using immunotherapy is probably the most time-intensive therapy, however it has the best potential return, with the least potential side effects.

The first step of immunotherapy is blood or skin allergy testing – this testing will identify which of several common allergens your pup is allergic to.

Intradermal testing is considered the “gold standard” and involves shaving a square of fur on your pup’s side, then setting up a grid and doing intradermal injections (into the skin layers) of the different allergens. These injection sites are then observed about 20 minutes later to see if inflammation occurs which suggests an allergic reaction.

Serologic testing, or blood testing in an alternative and involves drawing blood and sending it to a specialized lab which will test for reactivity within the blood that suggests environmental allergies. Serological testing can have a higher rate of false positives than intradermal testing thus making it less “ideal”. However overall it is potentially loss invasive to the pet.

Dog getting blood drawn for Serological Canine Allergy Testing, Intradermal Dog Allergy Testing shows a grid on a dog's shaved side.
Serological vs. Intradermal Allergy Testing

These results can then be used to create a unique serum for your pup containing TINY pieces of the allergens. The idea of immunotherapy is to expose your pup to the allergen in small, gradual increments to create a resistance to the allergen.

The serum usually has to be injected under the skin on a frequent basis – sometimes starting at every day or so, then tapers off to every couple weeks to months. During the first month of injections some pets will have increased itching on days when they are given the injection – if your pup experiences this reaction speak to your veterinarian, you may need to give antihistamines on these days in order to combat the reaction.

Though this therapy can be rather costly up-front the good thing is that with the use of therapy 50-80% of dogs see marked improvements to clinical signs after 12 months of therapy. Side effects are RARE, however in some cases anaphylaxis can occur.

Anti-Histamines

Some dogs will respond favorably with the addition of antihistamines to their routine, however research regarding this medication suggests that antihistamines are actually not very useful to help with itching during active infections or lesions. Making the use of this drug potentially limiting.

Steroids

The traditional treatment of itching and inflammation in dogs is done with the use of steroids. Steroids are very powerful and work well, however they also have fairly significant side effects and limitations. For example steroids cannot be given with NSAIDS – like carprofen or rimadyl – or it can lead to gastrointestinal bleeding. Also long-term chronic use of steroids can CAUSE pets to get medical induced Cushings which is a metabolic condition that requires long-term therapy. Other common side effects of chronic use include delayed healing, chronic bacteria/fungal infections, increased drinking and urination, increased eating, and more…

Thus many vets may use steroids as a short-term solution, but tend to seek out other medication for long-term medical management of environmental allergies.

Apoquel (Oclacitinib)

Getting rid of the itch without the steroids – apoquel is often-times touted as almost a miracle drug (released in 2014). It uses a different mode of action to basically decrease inflammation and itching like steroids do. But long-term use does not cause the same side effects that we see with steroids. However apoquel is currently labeled only for dogs over 12 months old, and has been shown to have some immune-suppressive properties.

Recently there has been some concern with apoquel’s side effects regarding long-term use:

“The manufacturer reports a variety of side effects in long-term studies, including decreased white blood cells, elevated liver values, and new cutaneous masses in up to 19 percent of cases. Apoquel is contraindicated with a history of previous neoplasia.”

Dr. Jason Pieper, MS, DACVD

Atopica (Cyclosporine)

Unlike apoquel which has a short-term action similar to steroids, atopica is much more of a long-term plan. Atopica does show similar anti-inflammatory and anti-itch properties to that of steroids and apoquel but it just takes longer to take effect. Typically it takes 6-8 wks of administration of the drug to see significant clinical changes. Thus often-times practitioners will pair atopica administration with a steroid for the first couple of weeks in order to get over that period before tapering off the steroids all together.

Another disadvantage of Atopica is that the medication tends to have side effects – vomiting and diarrhea – in the first 10 days of administration. Long-term side effects are related to the immunosuppressive nature of the drug, making a dog more prone to secondary infections – such as bacterial or function infections.

Cytopoint (caninized monoclonal antibody)

The newest drug to be added to the “toolbox” for veterinarians – released in December of 2016. Cytopoint is a once a month injection that can be used to reduce inflammation and itching in dogs with allergies. Side effects seen tend to be mild – the most common of which is lethargy within 24 hours post injection. However to-date there have been no long-term studies done on this product. Thus additional monitoring may need to be done with you pup between injections to monitor them more closely.

Now I want you to keep in mind that your pup’s management strategy may come from multiple different areas, and this is completely fine. What is most important here is to provide your pup with the best quality of life given their condition. I highly recommend working with your veterinary team to find which method or methods would be the most helpful for your pup.

WHEN TO SEE A SPECIALIST

There ARE veterinary dermatology specialists – these veterinarians specialize in skin and dermatology (just like in people) – and if you feel like you’ve been just going in circles at your normal veterinarian, it might be a good idea to seek on out. You can find one at The American College of Veterinary Dermatology – and if you live in an area without one available, call around to some specialists within your state and see if they would be willing to do a phone consultation between you and your veterinarian. A phone consultation done in this way may direct your veterinarian to new options, or testing that they haven’t done yet, or allow them to speak about possible management options in detail.

I really hope this article had all the information you were looking for in regards to environmental allergies and atopic dermatitis in dogs! Feel free to reach out if you have any additional questions, and make sure to join the community on Instagram to connect with other proactive pet parents and learn more about pet health, nutrition and wellness!

Love Nikki, Then Canien Health Nut and Registered Veterinary Technician
RESOURCES:

Veterinary Information Network – “Allergies: Atopic Dermatitis (Airborne)

Veterinary Information Network – “How I Treat: The Itching Dog

Merck Veterinary Manual – “Allergies in Dogs

Today’s Veterinary Nurse – “Scratching the Surface of Allergies in Dogs

University of Illinois School of Veterinary Medicine – “STEROIDS VS. ATOPICA VS. APOQUEL VS. CYTOPOINT

Today’s Veterinary Practice – “Dermatology and Nutrition

Today’s Veterinary Practice – “Diets and Dermus – Nutritional Considerations in Dermatology

Fritsch DA, Roudebush P, Allen TA, et al. Effect of two therapeutic foods in dogs with chronic nonseasonal pruritic dermatitis. Intern J Appl Res Vet Med 2010;8:146-154.

Lenox CE, Bauer JE. Potential adverse effects of omega-3 fatty acids in dogs and cats. J Vet Intern Med 2013;27:217-226.

Lenox CE. Role of dietary fatty acids in dogs & cats. TVP Journal 2016;Sept/Oct:83-90.

Bauer JE. Therapeutic use of fish oils in companion animals. J Am Vet Med Assoc 2011;239:1441-1451.

Noli C, et al. Efficacy of ultra-micronized palmitoylethanolamide in canine atopic dermatitis: an open-label multi-centre study. Vet Dermatol 2015; 26(6): 432-e101. 

Kapun AP, Salobir J, Levart A, et al. Vitamin E supplementation in canine atopic dermatitis: improvement of clinical signs and effects on oxidative stress markers. Vet Rec 2014:175:560.

Marsella R, De Benedetto A. Atopic Dermatitis in Animals and People: An Update and Comparative Review. Vet Sci. 2017 Jul 26;4(3):37. doi: 10.3390/vetsci4030037. PMID: 29056696; PMCID: PMC5644664.

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