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How Do Pets Get Allergies?

The following article is courtesy of our partner, Banfield Pet Hospital. Used with permission.

What is an allergy?
Allergy is a disease in which the immune system (the body’s protection system) reacts abnormally to substances such as fleas, pollens, mold spores, mites, and certain foods. All of these allergic reactions are unpleasant, some are serious, and a few can be fatal. The offensive substances causing allergies are known as allergens. An allergic reaction may be caused by inhaling or ingesting the allergen, but most often results from the allergen directly contacting the pet’s skin. Pets may be sensitive to several different types of allergens.

What are the signs of allergies?

How Do Pets Get Allergies?


Unlike people with allergies, pets usually don’t get stuffy or runny noses or watery eyes. The most common clinical sign of allergy in dogs and cats is itchy skin, which can lead to:

  • Scratching, biting, and chewing at the skin
  • Excessive face rubbing
  • Excessive grooming
  • Hair loss
  • Recurrent ear infections
  • Itchy rectal area (sometimes seen as scooting the hind end)

The usual locations of the itching are the belly, feet, base of tail, and face, especially around the eyes, mouth, and ears. These areas are often bright pink due to irritation. Less commonly observed signs include sneezing, coughing, asthma, diarrhea and vomiting.

How will my doctor determine if my pet has allergies?
Not all scratching is due to allergies. The diagnosis of allergies requires that the doctor first eliminate all other possible causes of the itching. Infections with fleas, mites, lice, bacteria or fungi; poor nutrition; or just dry skin may explain the itching. Your Banfield doctor will want to take a complete history of your pet’s problems along with a complete physical examination. Your doctor may also recommend laboratory tests such as blood work and skin scrapes to rule out other diseases and pinpoint what the problem is. Your doctor may also recommend a special diet and a food trial (where only one type of food is exclusively fed) in order to eliminate food allergy as a cause for the allergic symptoms.

How does my pet get allergies?
Your pet inherited its ability to be allergic from its parents. After continued exposure to the offending allergens for months or years, the signs of allergy become apparent in the pet. The typical allergic pet starts with a short period of biting, chewing and scratching which may be mild or perhaps unnoticeable. With repeated exposure to the offending allergens, the pet gradually experiences prolonged periods of itching and changes in the texture and color of the skin. In most pets, the initial signs of allergy appear during the first 2 to 4 years of life.

Can allergies be treated?
Just as in people, there is no cure for allergies. There are a number of different ways to treat and minimize the effects of allergies. If the allergy is mild, avoidance of the offending allergens in conjunction with environmental control may be all that is needed to control the disease. Your pet’s doctor may also prescribe medications such as steroids, antihistamines, fatty acid supplements, medicated shampoos and conditioners, or a special food to control the clinical signs. In pets with more severe allergies, or in pets where allergies occur year-round, specific allergy treatments such as immunotherapy (allergy injections) may be needed.

Immunotherapy is recommended because prolonged use of certain medications (especially steroids) can sometimes produce serious side effects that could potentially decrease the quality and length of your pet’s life. Your Banfield doctor will discuss various alternative treatments with you based on the needs of your pet. Symptoms of allergies can be uncomfortable and even painful, so the goal of treatment is to keep your pet comfortable.

Should my pet change diets?
Royal Canin and Hill’s Veterinary Diets have developed special diets to help pets with food allergies and improve the health of your pet’s skin. These diets are specifically designed with restricted protein and carbohydrate sources. They may also contain fatty acids to reduce the itching and improve the skin. Proteins (such as beef or chicken) and carbohydrates (such as corn) can cause allergy symptoms in some pets. If recommended, it is important to feed only this therapeutic diet to your pet, unless otherwise instructed by your doctor. During a diet trial, treats, rawhides and human foods must be avoided. Your Banfield doctor will determine if a therapeutic diet is best for your pet or if another diet is more suitable. Always consult your Banfield doctor before trying a different diet.

As always, if you have any questions or concerns about the health of your Pet, please contact your Banfield doctor.

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