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Most Common Causes of Allergies in Dogs and Cats

Canine and Feline Allergies and Their Causes


Most Common Causes of Allergies in Dogs and Cats

Fleas, foods and atopy are the most common causes of allergies in dogs and cats.


Allergies occur when your pet is abnormally sensitive to something to which he is exposed. Pets can be allergic to many different things. There are three common types of allergies seen in dogs and cats.

Flea Allergies in Dogs and Cats

flea allergies are the most common type of allergy. A flea allergy occurs when a dog or cat becomes infested with fleas and the fleas begin to feed on your pet. As the flea feeds, it's saliva secretes a substance to which some animals develop an abnormal sensitivity. An allergy to the flea is the result.

  • For dogs and cats that are allergic to fleas, one flea bite can be enough to cause a reaction.
  • Many dogs and cats that are allergic to fleas groom themselves excessively and some dogs and cats are quite good at removing the fleas. It can sometimes be difficult to find evidence of fleas on your dog or cat even if your pet is suffering from the symptoms of a flea allergy.
  • The symptoms of flea allergies can be prevented by preventing your dog or cat from becoming infested with fleas.

Canine and Feline Allergies Caused by Atopy

Atopy is sometimes called an inhalant allergy. It is an allergic reaction to something in the pet's environment.

Atopy can be caused by grasses, pollens, dust mites and many other substances. Finding the substance that is causing the allergy can be difficult. In some cases, systematically removing potential allergens (substances that may be causing the allergy) from the environment may help identify the cause. However, in most cases, skin or blood testing will be necessary to identify the offending item.

Your dog or cat may be allergic to more than one allergen also and these allergies can be cumulative. The symptoms of the allergy may become worse when a second allergen becomes present in your pet's environment.

In some dogs, atopy may be inherited from the mother and/or father.

Food as a Source of Allergies in Dogs and Cats

Foods are another potential source of allergies for your dog or cat. Food allergies are often caused by proteins in the food that act as allergens, causing an allergy for your pet. Carbohydrate sources can also act as allergens. Less commonly, other items in the food, such as preservatives or other ingredients, may be the cause of the allergy.

Physically, all of these allergies will appear identical to the others. The most common signs of food allergies in animals involve GI upset. Dogs and cats can also suffer from more than one type of allergy. It is not impossible for your dog or cat to be allergic to fleas and suffer from atopy or a food allergy at the same time.

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