How Do I Know if My Dog Has Allergies?

The following is an excerpt from Petfinder's FurKeeps Kickoff Ask the Experts Forum.

Q: We adopted a beautiful 10-month-old Golden Retriever a year ago from the Montreal SPCA. We are very happy with our adoptee! He is part of the family!

The only concerns we have are some skin problems. He has hot spots, ear mites, otitis, etc. I've always had Labs and I have been lucky -- no problems.

But what can we do to reduce the incidence of skin issues? It is almost every month we have to see the vet.

A: It's always hard to give a diagnosis (even preliminary) without seeing the patient. But I would certainly have skin allergies fairly high on my list of things that could be causing the repeat problems you are seeing with your dog.

Allergies in dogs can generally be broken down into two main categories:

  1. Allergies to things they are inhaling, such as pollen or ragweed. This is known as "atopy."
  2. Allergies to things that they are eating, more intuitively called "food allergies".

Unlike similar allergies in people, dogs manifest these allergies in the form of skin problems. Generally they are pretty itchy, which may include, outright scratching as well as licking or chewing their paws and rubbing their face and ears on the couch or carpet.

The skin inflammation leads to secondary problems, such as superficial bacterial infections, hot spots, repeat ear infections, and sometimes anal-gland infections. While these secondary problems or symptoms are often what gets noticed and can usually be cleared up with appropriate treatment, they tend to recur if the underlying allergic issue(s) are not addressed.

I would encourage you to speak with your regular vet and consider pursuing a referral to a veterinary dermatologist, but here is a very brief Dog Allergies 101:

Dogs can be atopic, food allergic, or (for an unlucky few) both.

Dog Atopy:

  • Because dogs with atopy are frequently allergic to pollens and grasses, they often have a seasonality to their symptoms but can show signs all year long if they are allergic to something that is always in the environment (such as dust mites).
  • Treatment of atopy centers around reducing exposure to the allergens, symptomatic treatment, and/or immunotherapy "allergy shots" like those people often require.
  • Some dogs have relatively mild, seasonal symptoms that can be managed with bathing and medications (such as omega-3 fatty acids and antihistamines, with the occasional use of steroids), while other dogs have more severe symptoms or suffer year-round and really benefit from the allergy shots.
  • The only way to truly diagnose atopy and determine what a dog is allergic to is to perform skin testing (again, like in people), and these results can be used to determine what to put in the allergy shots.

Dog Food Allergies:

  • For food allergies, diagnosis and treatment go hand in hand, and most vets will try to definitely rule out a food allergy before pursuing things like skin testing.
  • Because dogs can be allergic to even tiny amounts of the offending foodstuff, your vet will want to get a very detailed dietary history for you dog – including the ingredient lists for all the foods and treats you regularly give him.
  • Food allergies are diagnosed through something called an "elimination trial" or a "novel protein diet trial"  – your vet will suggest a diet made of ingredients that your dog has not been regularly exposed to. You will feed that diet (and here's the hard part  – only that diet!) for a period of 4-12 weeks. Dogs with a food allergy to something that they were previously eating will improve with the diet change, and if you go back to feeding the old diet, their clinical signs will recur.
  • Once you get the diagnosis, treatment is straightforward. Don't let the dog eat what he is allergic too. Unfortunately, as anyone who has ever lived with a dog knows, that is easier said than done!

Chronic skin issues can be tricky to diagnose, a real source of frustration for you and very uncomfortable for your dog. If you think your dog has skin allergies, a veterinarian with special training will be most equipped to handle a case like this.

Hope that is helpful,
Dr. Stephanie Janeczko D.V.M.
Medical Director
Animal Care & Control of New York City