Dog Allergies: Symptoms, Causes, Testing, and Treatments

Have you ever owned a dog who seemed to be itchy all the time? It can be frustrating. Maybe you've even found yourself raising your voice at your pup, begging them to stop scratching for just one moment of peace. As aggravating as this scenario must be for our pets, it can be even more frustrating for owners. After all, we love our dogs and want to help them, but how can we do that if we can’t figure out where the problem is coming from in the first place?

If you’ve already ruled out the more obvious causes of itchiness, such as a flea problem, a hotspot, or an injury, perhaps it’s time to consider another, more inconspicuous suspect… allergies.

As anyone who has suffered themselves can attest, allergies can be downright unbearable. And while symptoms of an allergy problem may not manifest the same in dogs as they do in humans, nearly 20% of dogs worldwide will suffer from chronic allergies during their lifetime.

For reference, this means that, in the United States alone, over 18 million dogs are currently combatting the same tormenting effects of chronic allergies that you and I may face. While not a go-to thought for most pet owners, the statistics don’t lie. If you find that your dog is incessantly itching, scratching, or biting at their skin, they, too, may suffer from allergies.

Where Causes Allergies in Dogs?

Allergies occur when a dog's immune system reacts negatively to something in their environment. This “something” is commonly referred to as an allergy “trigger,” which can be every day, airborne things such as dust or pollen. When your pet’s immune system senses the presence of these triggers, it will begin attempting to evacuate the substance itself from the body (even if it’s not actually harmful… but good luck telling that to the immune system).

To combat these perceived threats, your pet’s body will produce histamines to fight off the trigger. And while this might sound like a positive thing, histamines are largely responsible for many of your pet’s allergy symptoms, including redness and inflammation, itching, sneezing, and more.

More often than not, these allergy triggers are caused by something in your pet’s diet or in their environment. Figuring out which is the case for your own pet will be key to treating (and preventing) future allergy attacks.

Environmental Allergies

As is true in humans, your dog’s environment plays a significant role in their overall health. In fact, the large majority of dog allergy triggers are common, everyday things you might find in your own home or yard. In many cases, our pet’s allergies can be triggered by everyday household things that, at first glance, don’t seem problematic.

Common household triggers include:

• Dust mites
• Pollen
• Mold
• Trees
• Grasses
• Various fabrics
• Feathers
• Cleaning solutions
• Human dander

Yes, you read that last one correctly. As funny as it may sound, dogs can be allergic to people, too!

For most dogs, environmental allergies are seasonal. Allergy season can look different for every dog, though many pet owners find that their dogs get very itchy during the Spring and Fall seasons and less so during the Winter and Summer months. During these specified allergy seasons, many trees, flowers, and grasses are pollinating - a classic trigger for dogs and humans alike!

Food Allergies

As with their environment, your pet’s diet has a lot to do with their overall health and well-being. And while a true food allergy is difficult to diagnose, there are many ingredients in your dog’s food that they may develop a hypersensitivity to.

As previously stated, allergies occur when your pet’s immune system overproduces histamines in response to a perceived threat. In a reaction to food, your pet’s immune system is reacting negatively to some part of the food, NOT to the food itself. This is why it can be so difficult to diagnose what, exactly, your pet may be allergic to.

Practically any food ingredient can cause an allergy, though the most common culprits are proteins and carbohydrates. Some of the most well-known aggravators include:

• Chicken
• Beef
• Dairy
• Chicken eggs
• Soy
• Wheat gluten

It’s important to note that it takes a significant amount of time for your dog’s body to develop an allergy to a food item. If your pet were to develop a food allergy, it would usually evolve after prolonged exposure to one form, brand, or type of food.

Flea Allergies

Flea allergies are the third most common cause of allergy symptoms in dogs, aside from environment or food. This condition, officially known as Flea Allergy Dermatitis, occurs when a flea bites your dog and injects their saliva into the skin. This can happen even if your pet is on monthly preventative, as it only takes a single bite to leave your pup itching for days.

This type of allergy can be difficult to diagnose and is often done so based on clinical signs. One of the most common of which is sudden, extreme itchiness with no relevant history or identifiable cause. Pets suffering from a flea allergy often develop small, circular scabs at the bite site (usually at the base of the tail, the hind legs, or the neck).

What Are the Symptoms of Allergies in Dogs?

As with humans, every dog will react to allergy triggers differently and with varying levels of severity. However, some of the most common symptoms include:

• Itching and scratching
• Dry or "scaly" skin
• Hives
• Redness of the skin
• Ear infections (sometimes chronic)
• Hair loss
• Hotspots
• Chewing or licking at the paws
• Sneezing
• Coughing
• "Runny" nose or eyes (nasal or ocular discharge)

Some dogs may even experience gastrointestinal distress as a result of their allergies, which usually manifests in vomiting, diarrhea, loose stool, or loss of appetite. These types of gastric symptoms may be caused by inflammation in the body due to an overproduction of histamines.

Experts predict that most dogs will develop allergy symptoms in their youth (between 1-2 years of age). However, allergies have the ability to develop spontaneously at any time, especially in relation to a change of diet, routine, or environment (even in older dogs).

Can I Have My Dog Tested for Allergies?

Allergy testing is a great way to not only confirm that your dog does have an allergy but to discover what, exactly, he may be allergic to. While not inexpensive, allergy testing gives owners the opportunity to examine the core of their pet’s issues versus treating symptomatically year after year.

To determine which testing method is best for your pet, you must first attempt to narrow down the possibilities. Does your pet get itchier during certain parts of the year? If so, he may be dealing with seasonal or environmental allergies. If your dog is itchy year-round and has been on the same protein-based diet since he was a pup, perhaps you are dealing with a food allergy.

Unfortunately, there is no “one and done” test available. However, by narrowing down the possibilities, you can determine which option to pursue.

Testing for Food Allergies

Testing for a food allergy is most commonly done using a food trial. During this trial, your pet will be placed on a specified prescription diet (chosen by your veterinarian) and forbidden from consuming anything (and we do mean ANYTHING) else for several weeks.

If your pet’s allergy symptoms resolve during this period, your dog may, in fact, have a true food allergy. If this is the case, your next step would be to keep your pet on the same limited-ingredient food used during the trial as you begin reintroducing potential problem foods (chicken, dairy, soy, etc.).

Though statistically not as accurate as a food trial, there is also a blood-testing option for diagnosing food allergies. For this type of testing, an allergist will measure your pet’s blood for allergen-specific antibodies that compare to the ingredients in your pet’s food. You will then be tasked with choosing a limited-ingredient food that does not contain any responsive allergens (which may sound harder than you think).

Testing for Seasonal or Environmental Allergies

There are many effective ways to allergy test your pup for environmental or seasonal triggers. For starters, you can consider taking your pup to a veterinary dermatologist. Though not inexpensive, many pet owners see fantastic results from this type of collaboration with a specialist. Here, your dermatologist will perform a type of intradermal skin testing that is very similar to that of human medicine.

To start, your pet is sedated, and a small portion of fur is shaved down to the skin. Then, the dermatologist will inject a microscopic amount of common household allergens into the skin itself and monitor for a reaction. To treat, the reactive allergens are then mixed into an immunotherapy serum that is injected back into your pet over several months. While this type of treatment is not inexpensive, it does yield impressive results for pets with chronic allergies.

Another great option is blood testing if intradermal testing sounds too invasive. This method is often less expensive and can be done through your regular veterinarian. To start, your pet will have their blood drawn. This blood will then be spun down into serum and sent off to a testing center, where it will be measured for allergen-specific antibodies. If your pet is, in fact, allergic to something in their particular environment, an immunotherapy serum is created and administered at home over several months. This type of treatment is effective in about 60% of cases.

Allergy Treatment for Dogs

Fortunately, there are many great options for keeping your pet’s allergy symptoms under control. The best course of treatment for your own pet will depend on the type of allergy they have, the severity of their symptoms, and, of course, your own lifestyle and budget. With so many different options, from allergy shots to all-natural remedies, it can be tough to choose. A good first step? Taking a look at your pet’s food.

Best Dog Food for Allergies

As we discussed earlier, allergic reactions to food are less about the type or brand and more about the ingredients. If diet trialing or blood testing isn’t at the top of your to-do list, the next best place to start would be to get rid of known troublemakers such as chicken or dairy. Some online sources may also recommend cutting out grain. However, many recent studies have linked grain-free diets to heart disease, especially in large-breed dogs. So, as always, we recommend consulting with your veterinarian prior to changing your pet’s diet to ensure it is safe for their sex, age, and breed.

Some of the most allergen-friendly foods on the market include:

• Hill’s Prescription Diet: Z/D Skin & Food Sensitivities
• Royal Canine Prescription Diet: Hydrolyzed Protein (Hypoallergenic)
• Farmer’s Dog Fresh Food
• Wellness Simple: Limited Ingredient Diet

Many pet owners choose to cut out manufactured food altogether, electing instead for a home-cooked diet. While your pet would, no doubt, be thrilled at the prospect of a home-cooked meal, we would first advise that you speak with your veterinarian to ensure your pet is receiving a sufficient calorie intake and nutritional value.

Allergy Shots and Prescription Medications

When allergy season comes about in full swing, many pet owners will bring their dog in for an allergy shot, the most common of which is called Cytopoint. While not inexpensive (especially for larger pets), Cytopoint is extremely effective at reducing your dog’s itchiness. It does this by essentially blocking the “itch switch” in your dog’s brain, signaling the body to resist the urge to scratch. This type of allergy shot can be repeated every four to six weeks, as needed, during your dog’s specific allergy season.

If your pup isn’t a big fan of needles (and who can blame him?), allergy pills may be a better solution. One of the most common veterinary-prescribed allergy pills is called Apoquel and it works very similarly to Cytopoint. The biggest difference is that Apoquel is NOT a long-acting medication and must be given routinely to have an effect. Both of these anti-itch medications can safely be used long-term or as needed during allergy season.

It is not at all uncommon for some dogs to develop a skin infection as a result of their allergies. Tell-tale signs of an infection may include:

• Scabbing or "crusting"
• Severed redness or irritation
• Foul smell
• Sensitivity or pain when touched

If you are concerned that your pet may have a skin infection, consult your veterinarian immediately. If severe, your pet may require antibiotics, steroids, or an e-collar (the “cone of shame”) to clear up the infection.

Home and Natural Remedies

When a trip to the vet just isn’t doable, many owners will consider treating their pet’s allergies at home. There are many different ways to do this, from topicals to over-the-counter medications.

For starters, many dogs respond positively to the use of Benadryl or Zyrtec. While not meant to be used long-term, these doggy-safe drugstore meds may provide just enough relief to get your pet through their allergy season without a visit to the vet. However, we do recommend a quick phone call to your vet’s office to discuss dosage, drug interactions (especially for chronically ill pets), and side effects.

If medication doesn’t feel like the right solution, there are many effective at-home topical treatments to consider as well. Some fan favorites include:

• Apple Cider Vinegar (often used as a soak and beloved for its antibacterial properties)
• Coconut Oil (used as a lotion or a salve to soothe dry, inflamed, or irritated skin)
• Oatmeal (used in shampoo form or mixed in a bath, beloved for its soothing effects on the skin)
• Epsom Salt (used as a soak to relieve itchiness)
• Aloe Vera (applied directly to irritated patches of skin, should not be ingested)

Probiotics

Adding probiotics to your pet’s diet will not only treat their allergies but will improve their gut health as well. As the third most popular natural supplement used in humans, there are numerous health benefits to probiotics, many of which will benefit your pet’s itchy skin and coat!

According to Dr. Angie Kraus of Boulder Holistic Vet, “while probiotics don’t directly stop your dog from scratching, they do promote gastrointestinal health. Having a good population of healthy bacteria in the gut of your dog can drastically reduce and prevent allergies.”

There are several dog-friendly foods that are loaded with probiotics. Some of our favorites include:

• Yogurt
• Kefir
• Goat's milk
• Buttermilk
• Green tripe
• Broccoli
• Sweet potato
• Banana

There are also a variety of probiotic supplements available made specifically for dogs, such as our very own Probiotics for Dogs!

Living with Allergies

Unfortunately, curing your pup's allergies won't happen overnight. This is a chronic issue that many pets will battle lifelong, some more so than others. However, with a bit of love, patience, and a little help from your family vet, these symptoms can be kept quiet, allowing you and your pup to continue living a long, happy life together.