How common are allergies in dogs?

Extremely common, especially here in Fort Worth, Texas. We see allergies year-round. It is definitely in the top three, potentially the number one issue we encounter in our patients.

Dr. Shawn McCorkle
Summer Creek Animal Clinic

What are some common dog allergies?

I like to break it down into categories, especially when we're talking about skin allergies, which are the most common. Firstly, we have an environmental allergy category, which includes various pollen and things that humans would typically be allergic to as well. Dogs' immune systems often respond with skin issues instead of sinus issues like we do. This is not always the same in every situation, but we mostly see that with environmental allergies.

The second category is flea allergies. This is a category because fleas are such a big deal in Texas and flea allergies are super common. A helpful tip for a dog owner is to note if your dog itches along the back half of its body where the tail meets the back. If that is the primary itchy area, flea saliva is almost certainly the cause of the allergy. The good news is that this allergy can be managed quite well with the various good preventatives we have.

The third category is food allergies or allergies to a specific protein. With food allergies particularly, we again see it manifest itself with skin issues, but dogs will often also have concurrent GI issues like intermittent vomiting and diarrhea, or chronic diarrhea. So when we have a pet with GI upset plus chronic skin issues, a food allergy is more likely.

How do allergies impact the health and wellbeing of my dog?

With the exception of periodontal disease, skin allergies affect our pets' quality of life more than anything else. It's such a common problem that so many dogs struggle with chronically. It's like constantly feeling itchy. That's why they lick and bite their paws and scratch their ears. If your pet is consistently doing that, they are uncomfortable, and that's their way of showing us. It has a dramatic impact on their quality of life, especially when you end up on the more moderate to severe end of the spectrum of struggling with skin allergies either consistently through a particular season or year-round.

What are some signs and symptoms of allergies in dogs?

One big thing we see in dogs is ear infections. If your dog is scratching at their ears, shaking their head a lot, or if you see redness or gunk and discharge in the ear canal when you lift the ear flap, it means there's inflammation. Often, an ear infection, a secondary problem from the underlying allergy that's causing the inflammation, will result.

Ear problems, red ears, discharge, and smelly ears are all signs of inflammation. Outside the ears on the skin itself, we frequently see red bumps either raised or flushed with the skin, as well as circular crusts called epidermal collarettes. We also see thickened skin on the underside of the belly and the underside of the feet.

All of those things are signs of secondary skin infection. It is critical to understand that infection in the skin is rarely the primary issue. The bacteria and yeast that overgrow on the skin are naturally present in the dog's skin barrier. They're not able to colonize and cause problems. But when you add allergies, which cause inflammation in the skin, it allows for overgrowth of bacteria and yeast that cause these changes making the itching worse and causing additional skin problems on top of the underlying allergy.

Can I diagnose my dog's allergies at home?

No. People can sometimes discern what might be causing it based on the dog's lifestyle. Some dogs itch at certain times of the year. If your dog itches every August or September, and they're fine the rest of the year, most people can infer from that there's probably some sort of seasonal allergy. But even myself, as a veterinary professional, can't look at your dog and say with certainty that this is the underlying issue. Allergies are not that simple. Flea allergies are a bit different because of the way they manifest. We can be 99% certain in many cases that it is flea allergies or at least partly flea allergies. But apart from that, there has to be a methodical approach to determining the underlying allergies.

How will a veterinarian diagnose allergies in my dog?

We've already talked a bit about fleas, but I would like to add a note that is very important to understand as a pet owner. Most of the time, when I diagnose flea allergies, I won't find a single flea on the pet because fleas spend over 85% of their time in the surrounding environment. They just jump onto the pet to feed and lay their eggs, and then they're gone again.

If you've got a relatively mild infestation in the environment, you may never see a single flea on your pet. But if they are allergic to flea saliva, when that flea jumps on and bites them, their immune system overreacts and causes inflammation and itching that typically presents on the back half of the body. So just because you don't see fleas on your pet does not mean you don't have a flea issue. That's super important to understand. The only way you can be confident that you don't have a flea issue is if all your dogs and cats in the house or in the environment are on really good year around fleet prevention. Again, I'm focusing on the situation in Texas.

When it comes to the other two big categories of allergies, we take a lot of information based on the history of what's been happening to your pet and the frequency of problems to identify what type of allergy it is.

We also consider the type of presentation, like where the itching primarily occurs. From that information, we can at least get an idea of what is more likely, for instance, if it is environmental factors or food causing the allergy. To complicate things even further, about 20% of dogs will have a combination of both. Based on that information, we can determine which route to go.

Generally speaking, the first step is ensuring that all the pets are on good flea prevention. That helps us to control that category. Then we focus on a quality therapeutic prescription food trial. We mustn't start changing our pet's foods from one brand to the next because that won't tell you if we have a food allergy. It's will potentially expose them to proteins that make it more difficult to parse through later.

There's cross-contamination issues with over-the-counter diets that are just not part of the equation when they're making those foods. Without going into all the details, prescription foods help us hone in on if there is a protein allergy, and part of that process is maintaining tight quality control in terms of cross-contamination when those foods are made.

An eight to twelve-week food trial, where a dog gets absolutely nothing else in its mouth besides this prescription food, helps us determine if there is a food allergy in some of these cases. There's more to that, but that's the nuts and bolts of it. Once we've ruled out food allergies, or we're pretty confident it's not food allergies, the only way to adequately diagnose environmental allergies and determine what pollens and things in the environment your pet may be allergic to is through allergy testing. There are various ways to do that, including some blood testing, but it is generally not the best way to do it because the results are variable. The gold standard is still intradermal skin testing. Doing that appropriately and getting the most concrete information about what your pet is allergic to requires referral to the board-certified veterinary dermatologists.

It's not just about figuring out what they're allergic to. Knowing that they're allergic to St. Augustine pollen or grass doesn't mean much because you can't keep them away from that. You may be able to keep them out of the grass, but the pollen is still in the air. The point of allergy testing is to determine what they're allergic to and create a serum to give your pet chronically for the rest of its life. This will support its immune system in fighting allergies. That is the only direct way to treat environmental allergies. It's not a cure, but it helps the immune system directly fight the allergy.

How are dog allergies treated using anti-inflammatory therapy?

We in veterinary medicine have historically leaned very heavily on steroids with skin allergies. Steroids are great because they provide potent anti-inflammatory properties and reduce itching very quickly and effectively in most cases. The downside is that steroids have many other side effects on the body.

Personally, our clinic doesn't use steroids, except in very specific circumstances, because the risk factor is much higher than with some of the newer medications. So when we're talking about anti-itch medications, we aren't necessarily referring to anti-inflammatories but rather medication that blocks the itch, which is what most people look for.

We have new products that are extremely effective with much lower side effects and risk of complications. For example, Apoquel was the first effective product that came out. There are some potential side effects, but they're minimal and can be mitigated in most cases. An even newer option called Cytopoint has virtually no side effects because it's technically immunotherapy. Unless they have an allergic reaction to the injection, which is extremely rare, it will be so focused in the body that it only blocks the itch. So there are medicines that only target what we want them to. Those will be the future of veterinary medicine that is already apparent in how we manage allergy cases, particularly itching in dogs.

How is shampoo therapy used for dogs' allergies?

I am a big fan and proponent of topical therapy when it comes to allergies because it's often a chronic struggle for these pets, particularly dogs. We need to think broadly about managing and treating these cases. It's not just about giving medication or steroids that fix the problem short-term when there's no plan to manage things moving forward. Shampoos, in addition to other topical therapies like medicated mousses, are really helpful because they allow the pet owner, especially when the skin is healthy, to do things that keep that skin barrier as healthy as possible. So I like to use medicated shampoos, mousses, and sometimes sprays on a regular, consistent basis for many of these chronically allergic pets. It allows us to get better management at home.

If you still have other questions and you'd like to reach out to us, you can call us directly at (817) 523-1139, you can email us, or you can reach out on Facebook. But please do reach out, and we'll get back to you as fast as we can.

Dog Allergies - FAQs

Dr. Shawn McCorkle
Summer Creek Animal Clinic

How can you tell if my dog has allergies?

The first major thing we see with allergies in dogs is skin problems or itching. Itching is by far the most common symptom. Itching often looks intuitive in dogs. When a dog licks their paws, people will often think they're just cleaning its paws or it's a behavioral action. This may be the case, but more often, they're licking their paws because they're itchy, and they don't have the dexterity to scratch their hand like you and I would, so they lick or bite at their paw instead. Biting, licking, scratching their sides and ears, shaking their head, and rolling their back on the ground a lot are all things we see in dogs. It means they are itchy, and an itchy dog generally has skin allergies. Other things we might see are active skin lesions. This may include redness, red circles on the skin with crusts around them, hair loss, and swollen and red ears. In addition to that, allergies can sometimes manifest in GI problems. So if your dog is chronically vomiting or has diarrhea, a food allergy may be the cause.

How common are allergies in dogs?

Extremely common? Especially here in Fort Worth, Texas, we see allergies on a daily basis. It is definitely one of the top three things that we come across, and in particular seasons, it is the number one thing we encounter. So it is widespread in dogs.

What are the symptoms of allergies and dogs?

We mentioned itching being the most common thing we see. When we are looking for allergies in dogs at the hospital, we check for any discharge in the ear. That's a common occurrence, and it often means that there is inflammation in the ear because inflammation causes the glandular cells to produce more discharge. So if your dog's got a lot of junk in their ears, typically, that's an indication of inflammation. They would be scratching their ears and shaking their heads most of the time, but not always. So that's what we're looking for. We'll also look for any odor to the skin. Sometimes dogs have what's called seborrheic skin, which is an oily, unpleasant coat that is often associated with allergies. Other signs include skin lesions, hair loss, thickened skin, and darker skin, referred to as lichenified skin. In conclusion, we always look for an indication of unhealthy skin because it is almost always caused by underlying allergies.

What is contact allergy in dogs?

Contact allergies are things that a dog comes into contact with within the environment that triggers a certain reaction. When some dogs come in contact with particular things, it causes a certain type of allergic reaction that leads to hives, facial swelling, sometimes vomiting and diarrhea, or even in, in severe cases, collapse. It can be really dangerous. That's one class of allergies. Another type of contact allergy won't cause such severe hypersensitivity, but it can cause the immune system to respond abnormally, leading to inflammation and secondary infection. That type of allergy is what we typically see in allergic dogs.

How can you tell if my dog has a food allergy?

This is really important because I see this a lot with clients. They think their dog might have food allergies, and they use Dr. Google to try to discern what's going on. They then start switching their dog's food to various over-the-counter types of foods. That can potentially cause more problems in the long run because it exposes them to different proteins, which makes it harder to discern what the issue is.

The right way to identify a true food allergy, which is common in dogs, is to do what's called an elimination diet. That can be done in two different ways. The first is with a hydro protein diet, a prescription diet specifically created with the protein molecules broken into smaller pieces. That's what they mean by hydrolyzed. The pieces of the protein kind of go under the immune system's radar. The hope is that the immune system doesn't recognize them as foreign proteins leading it to respond negatively. This is the most common type of food trial we do because those foods are the most consistently readily available, and they tend to work really well.

The other type of food trial that can be done is called a novel protein food trial, which entails giving a protein that the dog has never been exposed to before. This can be challenging, and we'll have to make a thorough diet history. 10 years ago, people used kangaroo meat for this trial. I don't think it's used as much anymore because of the supply issue, but that would be a protein that dogs have never been exposed to before.

So we put them on a certain main protein to see if we can get the immune system not to respond to it.

Both food trials are trying to find out what the immune system will be happy with. Other critical things to consider before you go with any one of these routes include that it is ideal if these are prescription-level diets. Because they are formulated specifically for this purpose, they undergo quality control to minimize or eliminate cross-contamination. This can really only be guaranteed on a prescription level. So prescription diets are definitely the best way to go when we're working through a food allergy. The other two big considerations are firstly making sure your pet ingests no other food when they're in the trial period, which typically lasts for eight to twelve weeks. Ensure they eat nothing but the specialized diet, no food dropping on the floor, no human food, and no eating other dogs' food. Just the specialized diet food, so that we can eliminate everything else.

At the end of that food trial of eight to twelve weeks, we reintroduce the old food for over a week in duration, although we don't always do this. This is the best way to definitively diagnose a food allergy. If the dog has a significant food allergy and has been doing much better on the new food, they will start responding negatively when the old would is reintroduced.

That's how you definitively diagnose a dog with a food allergy. It's simple, but there are steps you have to follow in order to do it adequately, which can sometimes be a challenge.

Do dogs suffer from seasonal allergies?

Absolutely. That is actually the most common allergy we see when dealing with skin allergies in dogs. Humans would typically react to various things in the environment, such as pollen, and dogs would as well. Their immune systems react by causing inflammation in the skin. That disruption of the skin barrier leads to secondary infections in most cases.

We see seasonal allergies a lot. The complicating thing is that it'll just be seasonal in a lot of dogs because they're allergic to certain things determined by the season. But just because your dog has issues multiple times throughout the year or sometimes year-round doesn't mean that it's not "seasonal." By "seasonal," we mean environmental allergies. Because some dogs are allergic to so many things and the consequences are so severe, they will still have problems throughout the year, not just in the spring or summer. So it's not as clear-cut in that regard.

How are allergies in dogs different from allergies in humans?

I'm not a human doctor, but the biggest difference is that when we think of allergies in humans, we think of sinus problems and pollens, among other things that lead to this issue. Dogs have those same issues, but people tend to respond to similar allergens that dogs do with sinus problems, whereas dogs primarily respond with skin problems. So I think that's the big distinguishing factor. It's the same thing with food allergies. Humans can also respond to food allergies with skin issues, but that's more commonly the primary presentation of food allergies in dogs.

If you still have other questions and you'd like to reach out to us, you can call us directly at (817) 523-1139, you can email us, or you can reach out on Facebook. But please do reach out, and we'll get back to you as fast as we can.