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Seasonal Allergies in Cats and Dogs

Spring has sprung across our great land.  Sunny skies, tulips and crocuses…and itchy ears.  Or itchy bellies.  Or itchy paws.  Dogs and cats can develop hay fever or seasonal allergies just like ourselves.  Unlike people, who are prone to runny noses and stuffy sinuses, pets are more likely to show signs associated with skin lesions and ear infections when suffering from this condition.

Atopy is the term we use when we are describing an allergy to different particles in the environment.  The severity is often related to changing seasons.  Pets may become allergic to pollens, moulds, and dust particles (often dust mite “bits”).  We used to categorize atopy as the inhalant-form of allergies.  An animal would breathe in a specific particle that the immune system would recognize as foreign and set up an inflammatory response in reaction.  The inflammatory response usually involves the release of histamine molecules from particular cells concentrated in specific parts of the body-around the face and ears, the paws, belly, and around the anus.  This reaction results in pruritus, also known as itchiness.  The pet may start showing signs for a few weeks during the seasons when the offending particles are present in the air, but over time these periods may lengthen to the point that the pet shows allergic signs year-round.

We know that the inhalant route of exposure is very important, but research shows that dogs and cats are also being exposed to allergenic particles (proteins that cause your pet to develop an allergic reaction) through the digestive system and direct contact with the skin.  For example, during times of high pollen counts, your dog may be literally bathing in these invisible particles every time he goes outside.  When he licks a puddle, he may be drinking in these same particles.  Dogs don’t do well living in bubbles, so how do we diagnose and treat atopy?

Your veterinarian will diagnosis atopy based on a number of considerations.  Certain breeds are more prone to atopy than others including the Golden retriever, Dalmatian, West Highland white terrier, Shar Pei, Labrador retriever, Cairn terrier, Lhasa Apso, Shih Tzu, Boxer, and Pug.  The doctor will look for lesions or signs of scratching.  An atopic pet can have sore ears or red, swollen paws.  Dogs with allergies may have actual crusty sores on their bodies or may only have small areas of missing hair where they have been chewing.  Cats tend to have crusting around their faces and necks with or without signs of ear problems.  There are a number of tests recommended to ensure that there are no concurrent problems.  Skin samples will be taken to look for fleas, lice, Demodex, Sarcoptes, and other critters that can live on the pet and produce skin lesions.  Culture samples may be collected to rule out the presence of bacterial or fungal infections.  A large number of patients will develop secondary infections that require treatment at the same time as the allergies are being addressed.  Other conditions that cause skin disease may also need to be ruled out, and your veterinarian may advise specific testing for thyroid disease and other hormonal or immune-mediated problems.  Specific diet trials may be initiated to ensure that there is no food allergy component to your dog’s condition.  Specialized allergy testing is a great way to determine which allergens affect your pet.

Intradermal skin testing has long been considered the “gold standard” when diagnosing which specific allergens are causing problems for a pet.  The veterinarian will shave a small area on the patient’s side and draw a grid to keep track of the different allergens being tested.  A small amount of each substance is injected into the top layers of the skin and the spot is monitored for reaction.  Allergic pets will mount a “histamine response”, i.e. there is pin-point swelling and redness in the area.  The degree of reaction is rated by the veterinarian and recorded.  Some dogs and all cats will need to be sedated, because the histamine reaction we are looking for can be very itchy and uncomfortable.

Serum allergy testing certainly does have its place where clients do not have access to assessment by a dermatologist.  A small blood sample is taken from the patient and sent to a specialized laboratory that measures the amount of immunoglobulin E (a type of antibody) against specific allergens.  As an aside, although serum tests often offer food panels, most veterinarians recommend food allergy assessments through specialized diet trials.  The results for both intradermal skin testing and serum allergy testing need to be interpreted by an experienced veterinarian in light of the individual patient’s clinical symptoms, lifestyle, and environment.

As you can see, we generally don’t diagnose and successfully treat atopy with one visit to the veterinary hospital.  You may be asked to help control your dog’s environment with regular vacuuming and washing of bedding.  Stuffed toys and indoor plants may need to be removed from the home.  Air filtration devices incorporated into your air conditioning and heating systems can be very helpful in decreasing indoor allergens.  Once the doctor has ruled out other potential problems and treated any secondary skin or ear infections, therapy can be guided toward treating with prescription medications, and using hyposensitization techniques which allow patients to slowly become “immune” to their allergies.  Prednisone and other types of cortisone-type medications can be very useful in relieving allergy symptoms, although they are known to cause a number of side effects when used long-term.  Cyclosporine is another drug which may be of great benefit in the right patient.  Dogs and cats may have only a limited response to over-the-counter antihistamines, and your veterinarian will let you know if your pet is a candidate for these types of medications.  Nutritional supplements and topical products can also be used in addition to these main forms of therapy to decrease inflammation, boost the immune system, and soothe the skin. For most pets, atopy or other forms of skin allergies require chronic management. A great working relationship with your veterinarian will be the biggest factor in successfully reducing your pet’s symptoms and keeping the itchiness under control.

Article by Petsecure Pet Health Insurance

Dr. Colleen Skavinsky
Chief Veterinary Officer
Petsecure pet health insurance

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