Dog Allergies: Symptoms and Treatment

by Anna Burke

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.

Types of Allergies in Dogs
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.

Skin Allergies
Skin allergies, called allergic dermatitis, are the most common type of allergic reactions in dogs. There are three main causes of skin allergies in dogs:

Flea allergy dermatitis
Food allergies
Environmental allergens
Flea allergy dermatitis is an allergic reaction to fleabites. Some dogs are allergic to flea saliva. This makes affected dogs extremely itchy, especially at the base of the tail, and their skin may become red, inflamed, and scabbed. You may also notice signs of fleas, such as flea dirt, or even see the fleas themselves.

Food allergies and sensitivities can cause itchy skin, as well. The most common places dogs with food allergies itch are their ears and their paws, and this may be accompanied by gastrointestinal symptoms.

Environmental allergens, such as dust, pollen, and mold, can cause an atopic allergic reactions or atopic dermatitis. In most cases, these allergies are seasonal, so you may only notice your dog itching during certain times of the year. As with food allergies, 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.

Food Allergies
True food allergies may not be as common as people think, according to AKC Chief Veterinary Officer Dr. Jerry Klein. True food allergies result in an immune response, which can range in symptoms from skin conditions (hives, facial swelling, itchiness), gastrointestinal signs (vomiting and/or diarrhea) or a combination of both. In some rare cases, a severe reaction resulting in anaphylaxis can occur—similar to severe peanut allergies in humans

But what about all of those dogs that are on special hypoallergenic dog food diets?

What most people mean when they say that their dog has a food allergy is that their dog has a food sensitivity, also known as a food intolerance. Food sensitivities, unlike true allergies, do not involve an immune response and are instead a gradual reaction to an offending ingredient in your dog’s food, for example to beef, chicken, eggs, corn, wheat, soy, or milk.

Dogs with food sensitivities can present with several symptoms, including gastrointestinal signs such as vomiting and diarrhea, or dermatologic signs like itchiness, poor skin and coat, and chronic ear or foot infections.

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.

Acute Allergic Reactions
Perhaps the most alarming of all the types of allergies in dogs is an acute allergic reaction. Dogs, like people, can go into anaphylactic shock if they have a severe reaction to an allergen. This can be fatal if not treated.

Bee stings and vaccine reactions, among other things, can cause an anaphylactic response in some dogs, which is why it is always a good idea to keep a close eye on your dog following the administration of any new vaccine, drug, or food item. Luckily, anaphylactic reactions are rare in dogs.

Your dog may also develop hives or facial swelling in response to an allergen. Swelling of the face, throat, lips, eyelids, or earflaps may look serious, but is rarely fatal, and your veterinarian can treat it with an antihistamine.

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 to get an accurate diagnosis and to help your dog start feeling better.

Diagnosing Allergies in Dogs
If you have ever undergone allergy testing, then you know that diagnosing allergies is often complicated.

The first thing your veterinarian may choose to do 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, he or she 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.

Food allergies are often diagnosed using an elimination diet. A food trial consists of feeding a dog a novel (i.e. one) source of protein and carbohydrate for 12 weeks.

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.

Treating Allergies in Dogs
The best way to treat an allergy is avoidance of the cause and allergen. This may or may not always be possible. But, in terms of treatment, it depends on your dog’s type of allergy. 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.

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 him to an emergency veterinary hospital as quickly as possible.

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