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Could your pup be allergic to something in her food or her environment? Here's how you can help her find relief.

By Kate Eldredge Basedow, LVT
November 24, 2020
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While humans with allergies tend to sneeze, dogs with allergies tend to itch. If your dog has red, irritated skin and is constantly licking at her paws, she may be allergic to something in her environment or her food.

Allergies are common in dogs, and can be even more frustrating to diagnose and treat than in humans. When humans experience allergy symptoms, we can tell our doctor exactly what symptoms we feel and when it happens. Your dog can’t do that, so you and your veterinarian have to work together to figure out what is causing the issue and how to give your dog allergy relief.

Can All Dogs Have Allergies?

Yes, every dog is unique and dogs can have allergies to a wide variety of things. As the Baker Institute for Animal Health at Cornell University says, “Allergies are damaging responses by the immune system to environmental substances or by foods that are normally harmless.”

What Causes Allergies in Dogs?

Your dog may be exposed to the allergens through her food, insect bites, inhaling pollen or fungal spores, or even from brushing up against or lying down on a particular surface.

When your dog is exposed to an allergen, it triggers an immune response that leads to the release of histamines. Histamines are naturally occurring chemicals in your body, but too many of them can cause your dog a lot of discomfort, including inflammation, itching, and swelling. Depending on the source of the allergen and the severity and location of the response, the inflammation can cause a wide variety of symptoms in the affected dog.

Allergies can affect dogs of any age, breed, or mix. Some allergies are inherited, so allergies and other immune disorders in relatives are always a good thing to ask about when getting a puppy from a breeder.

Your dog can also develop allergies later in life as her immune system becomes sensitized to a particular allergen and starts to overreact to repeat exposures. Allergies often appear as a young adult. And as if all of this isn’t bad enough, your dog can also be allergic to more than one thing.

Types of Allergies in Dogs

Dog allergies can be classified in a variety of ways, including by the allergen (flea saliva, chicken, ragweed, etc.), route into the body (inhaled, contact with the skin, or consumed in food), speed of allergic reaction (anaphylaxis or immediate response vs. a delayed response), and clinical signs (skin lesions, respiratory signs, gastrointestinal signs). The most common breakdown used in practice is a combination of three categories: atopic dermatitis, respiratory allergies, and food allergies.

Atopic Dermatitis

Atopic dermatitis is both the most inclusive category of allergies in dogs and also the most common. Allergens in these cases are often inhaled, but can also trigger a response through skin contact. The allergens are found in your dog’s environment, and can include pollen and other plant materials, dust, dust mites, mold, fleas, shampoo, cleaning products, and even carpet fibers. Depending on which allergen(s) your dog is allergic to, she may show symptoms seasonally or year-round.

The common thread among causes is that your dog will show skin irritation. Skin irritation may be localized, often to the paws or ears, but can also affect your dog’s entire body. She may lick her paws constantly, staining them red from her saliva, or chew parts of her body until her hair falls out. She may get ear infections that keep coming back even after treatment by a veterinarian. Her red, irritated skin will be more susceptible to secondary bacterial infections, especially if her frequent scratching breaks the skin. The skin may also appear scabby with small, oozy lesions.

Insect and arachnid bites and stings can trigger acute allergic reactions. Fleas are a common culprit, and dogs with flea allergy dermatitis will break out in an itchy rash after even a single flea bite. If your dog is stung or bitten on her face or in her mouth, her lips and tongue may swell up. This is an emergency if her breathing is impaired. Bites on other parts of the body can also cause dramatic swelling and irritation, as well as extreme itchiness.

Contact allergies are usually responses to something that the dog is wearing (such as a new flea collar) or to a surface that she comes in contact with. These dogs will usually show a rash on the feet or belly where the body contacted the problematic surface (if reacting to a flea collar, the dog will have a rash where the collar contacts the skin around her neck). A reaction to a shampoo will likely affect any part of the body that was included in the bath.

Respiratory Allergies

Respiratory allergies in dogs are similar to the allergies most humans experience. These allergies are usually triggered by an inhaled allergen, such as plant pollen or dust mites, and cause the dog to show respiratory symptoms ranging from itchy, runny eyes to coughing and sneezing. Symptoms may be seasonal or year-round. Respiratory allergies are much less common in dogs than in humans and cats.

Food Allergies

There is a lot of misconception around food allergies in dogs. True food allergies are rare in dogs, and are usually a response to protein sources such as chicken, beef, dairy products, or eggs. An anaphylactic response to a food is even more rare in dogs. Dogs with food allergies usually show skin signs just like dogs with atopy, including itchy ears, licking at their paws, and/or a generalized rash over the whole body. Because their dermatitis is caused by food rather than something in the environment, dogs with food allergies usually won’t respond to the same treatments used for dogs with atopy. Some dogs may also show gastrointestinal symptoms, such as diarrhea or vomiting.

Symptoms of Allergies in Dogs

Dog allergy symptoms usually involve skin problems, but can also involve the GI tract and respiratory symptoms. Symptoms of allergies in dogs include:

  • Red, irritated skin (in one part of the body or generalized)
  • Itchiness
  • Licking at paws
  • Recurring ear infections
  • Recurring paw infections
  • Itchy rash on hind quarters (especially in flea allergy dermatitis)
  • Rubbing face
  • Hair loss (localized or generalized)
  • Hives
  • Swelling
  • Sneezing
  • Chronic cough
  • Runny eyes
  • Diarrhea
  • Vomiting

These symptoms all can fit with a variety of conditions and illnesses that may affect your dog, so it is important to work with your veterinarian to get an accurate diagnosis.

Testing Your Dog for Allergies

Dog allergy testing partly depends on what your dog’s symptoms are and what your veterinarian suspects may be causing her troubles.

There are a few main types of allergy testing for dogs, including intradermal skin testing, blood testing, and elimination diet trials, depending on the allergen.

  • Intradermal skin testing involves small injections of a number of different allergens and monitoring for your dog reactions. This information is then used to create a custom allergy serum to desensitize your dog to her triggers.
  • Blood testing is less invasive as it only requires a blood draw, but can also be less reliable than intradermal testing. An outside lab will test the blood, and the results can be used to formulate a custom allergy serum for desensitization therapy.
  • An elimination diet trial is the gold standard of testing for food allergies. This method involves working with your vet to put your dog on a diet with novel ingredients for 8-12 weeks, and then gradually start introducing foods back into your dog’s diet one at a time to determine the cause of her allergy.

Dog Allergy Treatment and Prevention

The best way to prevent allergy symptoms is to avoid the allergen. Obviously this is not always a simple matter—if your dog is allergic to grasses or trees native to your area, she can’t avoid exposure. Thankfully, there are some options for allergy medicine for dogs, and other strategies to keep your dog comfortable.

Flea Allergy Treatment

Treating a flea allergy is the easy one. Choose a product that repels fleas and kills them on contact without having to bite, and keep your dog on this year-round for protection. All other pets in your household should also be kept on a regular flea preventive to keep the house flea-free. Remember that even one bite can cause an allergic dog to break out in an itchy rash.

Atopic Dermatitis Treatment

  • Immunotherapy takes the results from allergy testing to create a custom serum with your dog’s allergens. This serum is then used to desensitize your dog to the allergens. You may also hear this treatment referred to as hyposensitization or allergy shots for dogs. Your dog will receive a series of injections on a set schedule to gradually desensitize her to the allergens that she is allergic to. Studies have found that 50 percent of dogs who undergo immunotherapy see significant improvement in their symptoms, and 75 percent of treated dogs don’t need as much medication to stay comfortable.
  • Corticosteroids such as prednisone can be used to relieve severe symptoms. Corticosteroids do come with the potential for some significant side effects, so they are usually used as a short-term treatment to provide your dog relief while another treatment has time to kick in. Some dogs do require a low dose of prednisone long term.
  • Allergy medications such as Apoquel (oclacitinib), diphenhydramine (Benadryl), loratadine (Claritin), and cetirizine (Zyrtec) can be used safely in dogs. Check with your vet for the appropriate dosage based on your pet’s size and allergy severity.
  • Cytopoint injections relieve itching by binding directly to the substances that transmit itch signals to the brain. One injection can last four to eight weeks.
  • Remove pollen and other plant materials to limit contact with her skin and the possibility of inhaling or swallowing them. Wiping your dog down with an unscented dryer sheet after walks will help to remove pollen from her coat and paws, or if your dog will tolerate it, you can also vacuum her after walks outside (carefully! The force of the suction can hurt your dog, so be sure to use a specially-designed dog vacuum attachment if you try this method).
  • Baths can also provide relief. Discuss with your veterinarian which type of shampoo would be most beneficial for your dog. Medicated shampoos are excellent for resolving secondary infections on the skin, and some shampoos will also help to restore normal skin health. Oatmeal shampoos can also be soothing to dry irritated skin. Following the instructions on medicated shampoos for leave-in times, rinsing, and frequency of bathing. Avoid bathing too often, as some shampoos can dry out the skin, making it more susceptible to damage and infection.
  • Fatty acid supplements are beneficial for healthy skin in general.

Respiratory Allergy Treatment

For dogs with respiratory allergy symptoms, such as allergic bronchitis, some of the same treatments as for atopic dermatitis can be helpful. Your veterinarian may also prescribe a cough suppressant if your dog is doing a lot of coughing to help her irritated throat heal.

Food Allergy Treatment

If your dog has a food allergy, medications such as steroids and Apoquel may provide some relief for your dog, but the most important thing is to avoid problematic ingredients. Don’t forget to check the ingredients on treats, too! If you stick to the appropriate diet, your dog will no longer experience allergy symptoms. Fatty acid supplements and probiotics may also be beneficial.

There is no single “best” dog food for allergies, but dogs who are allergic to a variety of ingredients may require a hydrolyzed diet. These diets, usually requiring a prescription from your vet, break the proteins down into tiny pieces so that your dog’s immune system won’t recognize them as a threat. 

In most cases, allergies in dogs can’t be cured. But with your vet’s help and some patience, you can find a treatment and management plan to keep your dog comfortable and symptom-free.