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Have you heard someone tell you that their dog has allergies? Has your veterinarian suggested that allergies could be a problem for your dog? Do you suspect that your dog has allergies? If so, then you’ve probably realized that allergies in dogs are not quite as simple as we might wish. For starters, there are several different types of allergies that could be causing your dog’s symptoms.

Allergies are a misguided reaction to foreign substances by the body’s immune system, which, of course, people and pets can suffer from. There are quite a few different types of allergies in dogs. Skin allergies, food allergies, and environmental allergens all pose challenges for dogs and their owners, and to make things more complicated, the symptoms of all these different types of allergies can overlap.

Golden Retriever scratching an itch on its head outdoors.
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Symptoms of Allergies in Dogs

The symptoms of allergies in dogs may vary depending on the cause. A dog that goes into anaphylactic shock, for instance, will have a drop in blood pressure followed by shock, which is very different from a skin condition.

In general, however, the following symptoms could be a sign of an allergic reaction.

  • Itchiness
  • Hives
  • Swelling of the face, ears, lips, eyelids, or earflaps
  • Red, inflamed skin
  • Diarrhea
  • Vomiting
  • Sneezing
  • Itchy ears
  • Chronic ear infections
  • Itchy, runny eyes
  • Constant licking

Some of these symptoms could also be a sign of another condition. Make an appointment with your veterinarian if you notice changes in their behavior to get an accurate diagnosis.

Types of Allergic Reactions in Dogs

Allergic Dermatitis in Dogs

Skin allergies in dogs, known as allergic dermatitis, is the most common type of allergic reaction in dogs. Skin allergies in dogs are mainly caused by one of three things:  fleas, food allergies, and atopic—or environmental—allergies. Flea allergy dermatitis is an allergic reaction to fleabites, and some dogs are allergic to flea saliva, which can cause their skin to become red, inflamed, or scabbed because their skin will feel extremely itchy. It’s the easiest type of allergic dermatitis to treat, since you can apply flea medication for dogs to help heal their skin.

Another cause of skin allergy in dogs is from food allergies and sensitivities. Just like humans can be allergic to certain foods or ingredients, dogs can be allergic, which can cause itchy skin. Dogs with food allergies usually have itchy ears or paws, sometimes along with gastrointestinal symptoms. Dr. Klein, Chief Veterinary Officer for the AKC, says that food allergies are not as common as you might think. True food allergies result in an immune response, which can range in symptoms from hives, facial swelling, and itchiness to gastrointestinal signs like vomiting and diarrhea – or a combination of both.

Environmental allergens can also affect the skin and be the cause of allergic dermatitis. Things like dust, pollen, fungus, and mold can cause these reactions, but in most cases, these allergies are seasonal. As with food allergies that affect the skin, the most commonly affected areas are the paws and ears (but also include the wrists, ankles, muzzle, underarms, groin, around the eyes, and in between the toes).

All skin allergies pose the risk of secondary infection. As your dog scratches, bites, and licks at his skin, he risks opening up his skin to yeast and bacterial infections that may require treatment.

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Urticaria, or Hives, in Dogs

Also known as urticaria, hives on dogs are very itchy but are not life-threatening. Hives appear as a reaction anywhere from 6 to 24 hours after exposure to allergens. This consists of itchy, swelled skin, that usually looks like a red rash. It’s easiest to spot hives on dogs that are hairless or have short coats. Dogs with longer hair can get them too, but it’s more likely that you’d be able to fee the hives rather than see them. Your vet will prescribe an antihistamine in order to treat urticaria in dogs.

Edema of Face or Throat

Swelling of the throat or face looks severe, but it’s actually almost never fatal. This area of swelling, which can also include swelling of the eyelids or ear flaps, is known as angioneurotic edema. It’s actually pretty easily treated, and despite how it looks, it’s a good sign in terms of allergic reactions.

If your dog has edema of any of these areas, the time for a fatal allergic reaction has most likely passed, and they aren’t in as much danger. Angioneurotic edema occurs anywhere from 30 minutes to a few hours after exposure to an allergen, and can also come with hives. A veterinarian will often give dogs with this reaction an antihistamine injection. Untreated, it may take a day or two for the swelling to subside.

Anaphylactic Shock

Perhaps the most alarming of all the types of allergic reactions in dogs is anaphylactic shock. Like people, dogs can go into anaphylactic shock if they have a severe reaction to an allergen. This happens when antibodies produced by the host react negatively to the allergen, dropping your dog’s blood pressure rapidly and sending them into shock. This can be fatal if not treated, but luckily, anaphylactic reactions are rare in dogs.

This can be a response to any allergen, most commonly bee or wasp stings, or vaccine reactions. Because of this, your vet will always recommend keeping a close eye on your dog after they’ve been given any new vaccine, drug, or food item, as they might be allergic.

If a dog has had a past incident and survived, the owner may carry an epipen, but sometimes the first occurrence can lead to death. Fortunately these reactions are very rare in dogs.

In some rare cases, a severe food allergy reaction resulting in anaphylaxis can occur, similar to severe peanut allergies in humans. The best way to diagnose and treat a food allergy is to work with your veterinarian to manage your dog’s symptoms and discover the ingredient causing the reaction.

Diagnosing Allergies in Dogs

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Flea allergy dermatitis is typically the easiest allergy to diagnose. It is usually diagnosed by identifying fleas on your dog’s body and applying a product that kills fleas before they can bite to see if that solves the issues.

The first thing your veterinarian will do in allergy testing is rule out any other condition that could be causing your dog’s symptoms. If your veterinarian feels that an allergy is a likely cause, they may propose allergy testing to try and determine the cause of the allergen that is causing the reaction. However, keep in mind it may not always be possible to determine the cause of an allergy with testing.

If you have ever undergone allergy testing, then you know that diagnosing allergies is often complicated. It’s the same for dogs, but it’s worth it to understand what to stay away from when it comes to your dog. Food allergies are often diagnosed using an elimination diet. A food trial consists of feeding a dog one source of protein and carbohydrate for 12 weeks.

Treating Allergies in Dogs

The best way to treat an allergy is avoidance of the cause and allergen, which may not always be possible. They type of treatment depends on the type of allergy your dog has. For example, the best way to treat flea allergy dermatitis is to kill the fleas, whereas the best way to treat a food allergy or food intolerance is a change in diet.

Depending on the cause and severity of your dog’s allergic reaction, your veterinarian will prescribe different things. For hives, they might suggest antihistamines, cortisones, medicated shampoos, whereas with food allergies they might suggest fish oil or other Omega-3 fatty acid supplements. For skin allergies, they might prescribe dog-safe anti-inflammatory wipes or shampoo on skin to provide irritation relief.

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In addition to any lifestyle changes that might be necessary, your veterinarian may also prescribe an allergy relief medication for your dog that will help control the signs associated with the allergic reaction, such as itching and any secondary skin infections that might have developed as a result of the irritant.

If your dog has a severe allergic reaction, your best course of action is to get them to an emergency veterinary hospital as quickly as possible.

This article is intended solely as general guidance, and does not constitute health or other professional advice. Individual situations and applicable laws vary by jurisdiction, and you are encouraged to obtain appropriate advice from qualified professionals in the applicable jurisdictions. We make no representations or warranties concerning any course of action taken by any person following or otherwise using the information offered or provided in this article, including any such information associated with and provided in connection with third-party products, and we will not be liable for any direct, indirect, consequential, special, exemplary or other damages that may result, including but not limited to economic loss, injury, illness or death.