Canine Allergy Basics

Discover the common causes of canine allergies.


In the simplest terms, allergy is the result of an immune system gone awry. When it’s functioning as it should, the immune system patrols the body, with various agents checking the identification (as it were) of every molecule in the body. It allows the body’s own molecules and harmless foreign substances to go about their business, but detects, recognizes, and attacks potentially harmful agents such as viruses and pathogenic bacteria.

When a dog develops an allergy, the immune system becomes hypersensitive and malfunctions. It may mistake benign agents (such as pollen or nutritious food) for harmful ones and sound the alarm, calling in all the body’s defenses in a misguided, one-sided battle that ultimately harms the body’s tissues or disrupts the body’s usual tasks. Alternately, the immune system may fail to recognize normal agents of the body itself, and start a biochemical war against those agents.

The three most common types of canine allergy are, in order of prevalence:

  • Flea bite hypersensitivity (known informally as “flea allergy”)
  • Atopy (also known as atopic disease or atopic dermatitis)
  • Food hypersensitivity (also called “food allergy”)

Flea bites, environmental allergens, and food account for the vast majority of cases of canine allergy. But dogs can be hypersensitive to all sorts of other things, including the bites of flies, mosquitoes, ticks, and mites; drugs, medications, and nutritional supplements; various fungal and yeast species; internal parasites (such as ascarids, hookworms, tapeworms, whipworms, and heartworms); and even their own sex hormones (in intact animals).

To learn more about common causes, best tests, and effective treatments for your dog’s allergies, download Canine Allergies today.