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Atopy (Seasonal Allergies)

By May 24, 2016 June 22nd, 2016 Uncategorized

Southeast Texas and allergies seem to go hand-in-hand.  The warm climate is great for lush tropical plant growth, but not so ideal for those of us, people and pets, who suffer from seasonal allergies.  Last month’s blog addressed allergies in general.  As promised, this blog covers in more detail one of the three major categories of allergies in pet – atopy.

Atopy is the term used to describe environmental allergies in pets.  Such allergies may also be known as inhalant or airborne allergies.  Atopy is a very common type of allergy in dogs, second only to flea allergy dermatitis.  A pet that suffers from atopy has an exaggerated immune system reaction to certain, often otherwise harmless, substances.

Unlike people with allergies who breathe in their allergens, the most common route of exposure in pets is through the skin.  Therefore, the feet, armpits and groin regions are the most commonly affected in dogs with atopy.  Dogs may scratch, chew and lick these areas, which become inflamed and irritated.  These sites have less protective hair and have the highest allergen contact.  Dogs with atopy also often have itchy faces and may rub them along the ground or furniture.  Less frequently, dogs can be affected by inhaling allergens and experience respiratory signs such as red, watery eyes and a runny nose.

Just about anything in the environment can be the inciting cause for a particular dog’s allergies.  The time of year your dog has a worsening of itchiness can be a clue.  In Spring, tree pollens cause the most problems.  The summer months bring grass pollens and outdoor molds.  And Fall flare-ups commonly are due to weeds as well as outdoor molds.

Year-round itchiness can also be due to “seasonal” allergies.  House dust mites, storage mites, indoor molds, moths and cockroaches can all cause atopy.  Even fabrics have been implicated in environmental allergies.  I once had a patient who was allergic to cotton – not an easy fabric to avoid.

To determine the exact allergens responsible for your dog’s signs, allergy testing is needed.  There are two options for testing.  The first is a blood test which measures levels of circulating antibodies to a variety of allergens specific to your region.  This test can usually be performed by your local veterinarian and is best done during peak allergy season for most accurate results.

The second option for allergy testing, called Intradermal Skin Testing, typically requires referral to a veterinary dermatology specialist.  Your pet is sedated and an area of the body is shaved.  Then tiny amounts of allergens are injected into the skin and the resulting skin reaction determines which allergens are factors in your dog’s atopy.

Once the culprit allergens are identified, a specific serum mixture is formulated for your pet.  Injections  or sublingual (under the tongue) allergen solutions are given in increasingly larger doses to build your pet’s immunity to these allergens, a process known as hyposensitization.  The overall success rate for this type of immunotherapy is about 70-85% with pollen allergies often responding best.   Results may take 4 to 14 months to be seen, so this therapy requires long-term commitment.

If allergy testing and hyposensitization injections are not an option, there are other therapies available for atopy.  Since skin exposure is the most important route, topical therapy is extremely important for a successful outcome.  Routine bathing with a hypoallergenic or veterinarian-recommended medicated shampoo at least once weekly should be done.  In addition, wiping your pet’s feet and underside with a damp cloth or baby wipes after coming in from outside will decrease the allergen load.

Corticosteroids have long been a mainstay in the treatment of atopy.  They can be a valuable addition to the therapeutic regimen when used in appropriate doses, forms and lengths of time.  However, the side effects associated with corticosteroids are numerous.  A medication called Atopica is the first FDA-approved oral medication specifically developed to control canine atopy.  It contains no steroids so may be a better option for long-term use, but it does not have the rapid effectiveness of corticosteroids.

Perhaps the most exciting development in canine allergy control is a medication called Apoquel.  Apoquel is a new class of drug that works by blocking the itch associated with allergies at its source.  It starts to control itchiness quickly (within 4 hours) and does not have the steroid-associated side effects.  It is also safe to give with other medications, labeled for long term use and is very well tolerated.  In fact, I have one of my own dogs (Bubba) on it year-round and have been amazed by its effectiveness.  By controlling Bubba’s itchiness and inflammation, Apoquel has virtually eliminated the hot spots and skin infections that he used to develop during peak allergy season.

Remember that allergies are never cured, only managed.  And a pet with allergies often suffers from more than one type.  So it is important to use a combination of therapies that provides the best control with the fewest risks of a negative health impact.  You must also realize that therapy is life-long.  There is no “quick-fix”, but with the guidance of your veterinarian you can help your pet have a comfortable, (almost) itch-free life.

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