Dog Allergies

dog allergies

Dog Allergies

By Travis McDermott DVM


Allergies are one of the most common reasons that dogs are presented to their veterinarian.  The key to managing dog allergies involves identifying the type of allergy the pet is pet is prone to and utilizing an appropriate mix of medications and treatment modalities.

Signs of Dog Allergies

The most common sign of dog allergies is itching or pruritis (the fancy word for itching).  That itching can manifest in many ways:

  • Hair Loss
  • Scratching
  • Chewing on Body (especially feet or back end)
  • Rash

Other common symptoms of allergies in dogs include:

  • Ear Infections
  • Skin Infections
  • Vomiting/Diarrhea

Causes of Dog Allergies

Dog allergies can have multiple underlying causes (sometimes more than one) including flea allergies, food allergies, and environmental allergies (atopic dermatitis).  Dogs can also have contact allergies which result from the pet touching something they have an allergy to, but they are much less common.

Flea Allergies

All of my Vegas people can pretty much ignore this section, but for the rest of the country, flea allergies are the most common reason for allergies.  Dogs affected by flea allergies are very sensitive to flea bites – so much so that one bite can cause a major reaction.   Flea allergies usually exhibit signs on the rear part of the back.

Food Allergies

Food allergies are caused by a reaction to some sort of protein or carbohydrates in a dog’s food.  Symptoms usually are seen around the face and under the legs.  Diagnosing food allergies is accomplished by putting the dog on a food trial.  A food trial involves feeding a very strict diet for 8 weeks and monitoring for improvement of the allergies.  Avoidance of the offending source is the best treatment.

Environmental Allergies (Atopic Dermatitis)

Environmental allergies include allergies to pollens, molds, trees, and other particles that float in the air.  Symptoms usually show in the ears and on the front feet.  Avoidance is next to impossible, so treatment usually involves medication or hyposensitization shots.  The good news is that we now have much better medications available for allergies than in the past.

Treatments for Dog Allergies

There are numerous treatment options for the different causes of allergies and the issues they create.


Medications like Benadryl (diphenhydramine) block the histamine reactions that occur with allergies.  When combined with omega 3 fatty acids, they control about 40% of allergy cases.  These medications can be purchased over the counter and have very little (if any side effects).

Omega 3 Fatty Acid (Fish Oil) Supplementation

Better known to most people as Fish Oil, omega 3 fatty acids have numerous benefits as a supplement including help with the skin and hair coat.  Every dog should be on a fish oil supplement even if they don’t have allergies.   Check out our blog on Pet Supplements for more information on Fish Oil and other beneficial supplements.

Canine Atopic Dermatitis Immunotherapeutic (Cytopoint) Injections

This injection uses new technology similar to vaccines to block the most common mediator of allergies in the body.  The injection is given once a month (some pets need it less frequently) and has minimum (if any) potential side effects.  See more information at

Immunosuppressive Medications

This category of medications work by suppressing the portion of the immune system that reacts to allergies.  Common immunosuppressive medications include:

  • Steroids – These medications have been used for decades to control allergies.  They work very well, but  have numerous short term (and potentially long term) side effects.
  • Cyclosporine – This medication (commonly used in humans to prevent organ rejection in transplant patients) helps control allergies, but can make patients nauseous.
  • Apoquel – This medication works as well as steroids in preventing itch without the side effects.  It acts quick in addressing allergies and is often used for long term management of allergies.

Hyposensitization Shots

Hypsensitization shots (ie allergy shots) work by injecting a small amount of the compounds that cause allergies for the dog (each set of shots is specific to the patient they are being used for).  This medication does not work for every patient, but a majority of dogs will see at least some improvement.

Medications that Treat Secondary Infections

One of the biggest complicating factor for any allergy patient is the development of a secondary skin infections.   These can be either bacterial or yeast infections and can may cause a dog to be just as itchy as the allergy that created them.  Antibiotics and antifungals are often used in conjunction with allergy medications.

Flea Control

This one is probably pretty obvious.  As mentioned above, flea allergies are the most common allergies for dogs not living in Vegas and avoidance is the only treatment.  These medications (now available over the counter) help prevent flea infestations.

Is there a Cure for Dog Allergies?

Allergies are a very common condition in dogs and can be extremely frustrating.  There is no cure for allergies and while they can be managed with a combination or the above medications, dogs with allergies will still often flair up with issues a once or twice a year.

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