Got the itch???


Does your dog suffer from itchiness, aka pruritus? Did you know they could be suffering from allergies?

While itching in itself is a normal sensation that exists to provide a stimulus for self-grooming and the removal of parasites and harmful objects or substances from the skin sometimes it doesn’t remove the inciting stimulus that caused the itching in the first place. In this case the itching would be considered abnormal. While there are many reasons for an animal to be itchy the discussion of potential allergies often arises.

So what are allergies?

Allergies are considered an abnormal response of the immune system. In animals with allergies the immune system reacts to a usually harmless substance in the environment, or allergen, as if it were harmful (even though it’s not) usually after often repeated exposure. In the case of dogs there are 3 major types of “allergies” we usually encounter that we will discuss.

  1. Atopic dermatitis (allergic dermatitis, canine atopy) is an inherited predisposition to develop allergic symptoms following repeated exposure allergens such as dust mites or pollen. Most dogs begin to show clinical signs between 1 and 3 years of age. Due to the hereditary nature of the disease some breeds are more commonly affected by this condition than others, however even mixed breeds can present with atopy. Atopic animals will usually rub, lick, chew, bite or scratch at their feet, muzzle, ears, armpits or groin, causing hair loss, and reddening and thickening of the skin. Atopy can be either seasonal or year round.
  2. Food allergy involves reaction to a particular antigen or allergen in the food. Most typically this is the protein source of the food however can be other nutrient sources in the diet. Signs are variable and food allergy dermatitis can present as simple irritated ears and rears however can also be very similar to that of atopy making diagnosis difficult. Clinical signs tend to show no seasonality and are less responsive to medications. Animals are most typically presented as older puppies or young adults.
  3. Flea allergy dermatitis involves development of allergic symptoms in response to the polypeptides found in the flea saliva. The most common age of onset is 10 months to 5 years of age and lesions usually involve papules and crusting. Flea allergy dermatitis symptoms can vary however in general it is extremely itchy and most lesions that the owners note are actually secondary, self-inflicted injuries due to scratching. Animals with atopy are predisposed to the development of flea allergy dermatitis and it is important to note even minimal exposure may be enough to elicit extreme clinical signs in a sensitive animal (i.e. there does not need to be a flea infestation). Signs are more commonly seen in the warmer months with flea season however can be year round if flea control is not achieved.


In some cases several skin problems can add together to cause an animal to itch where just the allergy alone would not be enough to cause itching. Eliminating some of the problems may allow a patient’s itchiness to go away. Therefore it is important to treat any other problems that could be making your pet itch while dealing with allergy.

The diagnosis of allergies can be frustrating for veterinarian, patient, and owner as clinical signs can be similar for different types of allergies making diagnosis difficult. However, once the type of allergy is determined it can be managed and quality of life improved. It is important to realize that just like in us there is no cure for allergies in our pets.

Dr. Stephanie Gunsinger