Allergies in Dogs and Puppies: Signs, Causes, and Treatment

Katy Nelson, DVM
Jun 30, 2020
   |    6 min read   |    Share this:

Does your dog or puppy itch, scratch, chew, or lick themselves excessively? These are all signs that your dog may have allergies.

Allergies are common in dogs—in fact, they are one of the top reasons for veterinary appointments. Dog allergy symptoms more commonly affect the skin and ears. 

While humans often outgrow allergies, allergies in dogs tend to worsen as they get older. So how do you know if your dog has allergies and what’s causing them? What’s the best allergy treatment for dogs?

Here’s what you need to know about dog allergies signs and what you can do to relieve your dog’s allergies.

Types of Allergies in Dogs

Here are a few of the different types of allergies a dog can have.

Flea Allergies

An allergy to fleas is the most common skin disease seen in dogs. The bite of just one or two fleas per week is enough to make affected dogs itch. Flea saliva is believed to be the allergen that causes the itchiness.

Seasonal/Environmental Allergies

Also known as atopy, seasonal or environmental allergies are caused by substances that exist in your home, backyard, and anywhere else your dog spends time.

These allergens can be inhaled, as with pollen, as well as absorbed through the skin when your dog touches them. Common triggers (allergens) for these allergic reactions include pollens, plant or animal fibers, dust mites, and mold spores.

Food Allergies

These are also known as adverse food reactions. Dogs can develop an allergy to a particular food at any point during their life, regardless of whether they have eaten these brands or types of foods in the past. 

The most common food allergy for dogs is to a protein source in the diet, but sometimes the allergy is to grains and/or other ingredients.

Dog Allergies Signs

Dog allergies signs can include:

  • Itchy skin
  • Scratching
  • Licking
  • Face rubbing
  • Red skin
  • Loss of fur
  • Recurrent skin and ear infections
  • Gastrointestinal (GI) signs

The type and severity of these dog allergies signs depend partly on the type of allergy your dog has.

Signs of Flea Allergy Dermatitis in Dogs

The most common symptom of flea allergy dermatitis is itchy skin and irritation at the base of the tail, although other areas of the body may also be affected. 

Seasonal/Environmental Allergy Signs in Dogs

Common symptoms include scratching/itchy skin, licking (especially the paws), and face rubbing.  Affected dogs may also experience red skin, loss of fur, and recurrent skin and/or ear infections. You may see red skin or fur loss on your dog’s paws and lower legs, face, ears, armpits, and belly.

Signs of Food Allergies in Dogs

The symptoms of food allergies are often the same as for seasonal/environmental allergies. There may also be GI signs, such as diarrhea, vomiting, or an increased number of bowel movements per day.

Is There an Allergy Test for Dogs?

Allergy testing in dogs is done for seasonal/environmental allergies only. Studies have shown that blood testing and skin testing for food allergies are not accurate in dogs.

Prior to performing allergy testing, your veterinarian should rule out other causes for your dog’s allergy symptoms.  Allergy testing should not be used to confirm that your pet has seasonal/environmental allergies, but to determine the specific things to which your dog is allergic. 

Studies have shown that hair and/or saliva testing for seasonal/environmental allergies or food allergies in dogs is not accurate.

Seasonal/environmental allergy testing can be performed in dogs by either skin testing or blood testing. Skin testing is the most accurate type of allergy test, and it’s generally performed by board-certified veterinary dermatologists.

Mild sedation is required. The fur is clipped in a small area, and a series of very small amounts of allergens are injected into your dog’s skin. The degree of the allergic reaction to each allergen determines whether your dog is allergic to it. The cost of these tests can range from $300 to $700.

Dog Allergy Treatment by Type

The treatment of allergies will depend on what the vet determines your dog is allergic to. Here are a few examples of how your vet might approach the treatment of allergies.

Treatment for Flea Allergies

Treatment for flea allergy dermatitis is aimed at reducing the symptoms of itchy skin and irritation until the fleas are eliminated. To eliminate allergy symptoms in a flea-allergic dog, strict flea control is required.

There are many highly effective flea control products and medications available. Some are topical and come in the form of a liquid that you squeeze onto your dog’s skin, such as Advantage, Revolution, or Vectra. Others are given orally in the form of chews, such as Simparica, NexGard, or Comfortis. Consult with your veterinarian to determine your best option. 

In severe cases, a dog’s environment must be treated for fleas as well.  Vacuum thoroughly to remove eggs, larvae, and pupae, and discard the vacuum bag. You can use insecticides inside and outside your home to treat all flea life stages.

It is important to use an insecticide containing an insect growth regulator, such as methoprene or pyriproxyfen, to halt the development of flea eggs and larvae. You can hire a professional exterminator, but you should specify that the treatment is for fleas. 

Treatment for Food Allergies

The treatment for food allergies in dogs is to feed a hypoallergenic diet for 8-12 weeks. This is the only way to determine if your dog has a food allergy. 

Hypoallergenic diets either have limited ingredients with an uncommon protein source or are processed in a special way (hydrolyzed) to be less likely to cause allergic reactions. The concept is that a dog cannot be allergic to a food that it has not been exposed to before.

Consult your veterinarian to choose the proper diet. Over-the-counter foods are not recommended for a proper food trial. Treats, flavored medications, and human foods may also have to be eliminated during this trial period. 

Other allergy treatment for dogs are aimed at reducing the symptoms while waiting to see if the diet change is helpful. Cytopoint, Apoquel, or steroids may be used to help control itching while waiting to see if a hypoallergenic food trial results in improvement of your dog’s allergy symptoms.

Treatment for Seasonal/Environmental Allergies

If allergy testing has not been performed, then the treatment is symptomatic, meaning that it aims to reduce or eliminate your dog’s symptoms. Treatments can include:

  • Oral medications, such as Apoquel, Atopica, or antihistamines

  • Injectable medications, such as Cytopoint

  • Fatty acids

  • Steroids

  • Frequent bathing

Steroids should not be used long-term in the management of allergies due to the risk of significant side effects.

If an allergy test has been performed, then the ideal allergy treatment for dogs is avoidance of the allergen. This is possible in a few, select circumstances, but most dogs are allergic to a variety of substances that can be difficult to avoid completely.

Other treatment can include an allergy vaccine, also known as immunotherapy, which is given either by injection under the skin (allergy shots) or by mouth. The goal of immunotherapy is to make the immune system less reactive to the allergy-causing substances.

The success rate of immunotherapy is 60-70%. This is the best long-term approach to allergy control, especially in younger pets that experience symptoms most of the year. Symptomatic treatment can and should be given while starting immunotherapy. It may be many months before any improvement in symptoms is seen from immunotherapy alone.

Featured Image: iStock.com/bruev

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