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Pet Allergies

Updated: Dec 10, 2021

There are new treatment options in  allergy treatment!

Apoquel® is a new drug that has the potential to greatly assist allergies in dogs. See the recent article on our website.

CADI Injections (Canine Atopic Dermatitis Immunotherapeutic) are a new, long-lasting, targeted and safe treatment option for dogs suffering with allergies.

If you are interested in learning more details concerning allergies and the source of the sensation for itching, here is a great resource for you to review. You will understand both why pets itch as well as how different treatments listed on this page assist in reducing itching.

Even though allergies are common, treatment can be very frustrating. Just as in people, treatment of allergies is primarily directed at reducing the symptoms and increasing patient comfort.

What causes allergies?

In dogs, atopic dermatitis is known to be, in part, an inherited disease. The main allergic reaction is to proteins absorbed through the skin. For years, we have considered atopy to be the results of allergens that are inhaled. Experts in veterinary dermatology now know that most allergens exert their effect directly through the skin.

Skin barrier defects contribute to the the disease. (Follow this link for more information on skin barrier defects). Primary skin disease may predispose pets to allergies rather than a faulty immune system. Anything we do to improve the health of the skin will benefit pets with allergies.

Bacterial and yeast infections provide additional antigens which may worsen pruritus (itching).

How are allergies diagnosed?

The diagnosis of allergies is normally based on history, physical examination, patterns of skin disease, and response to certain treatments.


Clues such as the seasons when a pet is affected, the environment in which the pet lives, the age of first symptoms, and the response to previous treatments can assist in the diagnosis of atopy. Atopic dermatitis can occur in any breed of dog but there is an increased risk reported in Irish Setters, Dalmatians, West Highland White Terriers, Scottish Terriers, Wire Hair Fox Terriers, Boston Terriers, Cairn Terriers, Lhasa Apsos, Miniature Schnauzers, Beagles, as well as Labrador and Golden Retrievers.

Physical Examination

Many skin diseases look alike when first examined. The skin has a limited number of ways of reacting to different diseases. Areas of the body most frequently affected by allergies are the ears, paws, legs, and the ventral abdomen. Other areas affected less often are the eyes, the muzzle and face, the axillary area (equivalent to our armpits), and the area around the anus.

Response to Treatment and Allergy Co-Factors

Skin infections caused by bacteria and yeast can look like atopic lesions. These infections can aggravate underlying allergies. Initially, if a skin infection is diagnosed, treatment for this infection begins. Many pets with atopy require antibiotics frequently or for extended periods of time. We are often concerned about indiscriminate and long-term use of antibiotics. You may be familiar with the term MRSA, which is a very dangerous strain of Staph that is resistant to many of our common antibiotics. Treating skin disease without using other methods of allergy control is unwise and potentially dangerous.

Yeast infections of the skin are a common finding with atopy. The primary pathogen is  usually malassezia (yeast).

Other contributing factors to atopy are ear infections, hypothyroidism and fleas (though fleas are very rare in Gilbert, Chandler, and the surrounding areas). Mites (demodex, sarcoptes) can cause symptoms in pets that mimic allergies and, therefore, must be ruled out. Any resistant or recurring case of allergies will require additional diagnostic work up or treatment for the above causes.


There are four groups of options for the treatment of atopic dermatitis. They include:

  1. Supportive therapy (improvement in the health of the skin and hair coat)

  2. Steroids such as Prednisone

  3. Apoquel® and CADI injections

  4. Allergen specific immunotherapy (after testing to determine the specific allergens that affect each individual pet)


As some allergens are absorbed via the skin, it makes sense to rinse the skin and bathe as needed. While bathing too frequently with harsh shampoos can dry and aggravate sensitive skin, simple rinsing with cool water after walks has been shown to reduce allergy symptoms.

Medicated shampoos are used depending on the findings at the time of the exam. Some shampoos are “hypoallergenic” and can be soothing. Other helpful kinds may contain oatmeal, colloidal components, and topical antihistamines. Still, some are medicated with ingredients that treat bacterial and yeast infections while reducing dryness.


As noted above, many allergic dogs have bacterial skin infections. Typically, if the skin is red and inflamed, pets will be treated with an appropriate antibiotics.

Thyroid Disease

In many cases, dogs with atopy and ear infections have low thyroid function (hypothyroid). This diagnosis is made with a blood test.

Ear Care

Much can be said about the role of atopy in ear disease. Obviously, pets with floppy ears or pets that get their ears wet frequently are more likely to have chronic ear infections. Ear infections can be painful and should be treated as soon as you suspect that there is a problem. Signs include shaking the head, scratching at the ears, a foul odor coming from the ear, or whining when you pet the head or rub the ears.


Though this article focuses on atopy or inhaled allergies, food allergies are a common problem as well. The diagnosis of food allergy is simple, yet can be quite difficult. Food allergies usually start at a younger age (less than one year) and respond poorly to standard allergy treatments. Establishing a diagnosis of food allergy requires that a pet eats only a novel hypo-allergenic diet on a trial basis to see if there is improvement in the signs. Such a diet is designed to introduce a unique protein and carbohydrate source that the pet has not eaten before. Strict adherence to this trial diet for 6-8 weeks is required to have any meaningful way of determining if food is a part of the allergy complex.


Some pets have allergic reactions to things with which their skin may come in contact. In cases like this, we may advise you to get new bedding, and remove or avoid certain grasses such as Bermuda or Winter Rye grass. We may also advise you to replace plastic bowls with stainless steel or porcelain.


Acknowledging the history of skin problems, clients often respond that they have tried Benadryl or some other antihistamine to control itching or allergies. Unfortunately, few pets derive much relief from Benadryl. Because antihistamines are relatively inexpensive and safe, their use to treat atopy is warranted. Benadryl happens to be one of the least effective antihistamines, unfortunately. We have seen that some dogs respond positively to one specific antihistamine, while others respond best to another. Two antihistamines with the greatest efficacy in pets are Cetirizine or Chlorpheniramine. We recommend trying any antihistamine for at least 10 days. If the first drug proves to be ineffective, a trial with a second or even a third antihistamine should be done to determine if there is any benefit.


When several steps have been taken with little relief, we may recommend hyposensitization therapy with allergen-specific serum. This serum (or “allergy shot”) has high concentrations of the proteins to which your pet is most allergic. Each pet has a unique profile of allergens that trigger disease. The best method of determining what your pet is allergic to is with intradermal skin testing. This test is usually performed by a veterinary dermatologist. An alternative method is to perform a blood test which assays the pet’s serum and indicates which allergens are the most reactive. The goal of both skin testing and serum testing is to create a specific combination of allergens that are injected into the pet over time and in increasing doses.  Based on client questionnaires, successful outcomes for this form of treatment average about 60-70% after one year.


Atopica® (Cyclosporine) is a drug that modulates the immune system and treats allergies. It has certain advantages over steroids (detailed in the next paragraph) in the treatment of allergies. Before Apoquel®, this was a valuable drug in our arsenal against allergies. Some pets still respond better to Atopica® than to newer therapies.

Glucocorticoids (Steroids)

Before Apoquel® and CADI Injections, most pets with atopy were treated with some form of a steroid. Prednisone or Prednisolone are the most commonly used steroids for allergies, but other drugs such as Medrol, Triamcinolone and Depo-Medrol are used as well. They are usually cheap and effective, however, the problem lies in the fact that there are potentially dangerous side effects with long-term use of steroids.


If your pet has atopy, we want to be your teammates in providing the best care and quality of life for him or her. As we review the treatment options, don’t become bewildered at the various drugs, sprays, shampoos, ear care products, and antibiotics we may dispense or recommend. Allergy treatment involves some trial and error. As safer and more effective treatments are discovered for managing allergies, we have the opportunity to improve the life of pets suffering with allergies. 

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