Pet Allergies - Part 2

November 2006 - by Doctor Denise E. Roche, D.V.M.
To read the first of these two articles - click here  

The first article discussed what allergies are and how they are triggered.  This article reviews the treatments available for an allergic patient. Keep in mind that each allergy patient is different and each treatment will be individualized to that pet. Some therapies will work better than others for different pets. Above all, remember that allergies are controlled at best.  Allergies are not cured. Close communication with your veterinarian is essential in keeping your allergy pet as comfortable as possible.

BATHING:  Frequent bathing helps physically remove irritants that are on the surface of your pet’s skin.  Bathing also helps control and removes infection causing bacteria from the skin.  Some pets need be bathed weekly. It is very important to use a high quality, hypoallergenic or medicated shampoo that will not dry out or irritate your pet’s skin when used regularly. Be sure to thoroughly rinse your pet after its bath. Your veterinarian will recommend the best shampoo and the best bathing schedule for your pet.  Consider having your long-haired pet’s coat shaved during allergy season to assist you in bathing.  

ANTIHISTAMINES: Antihistamines work the same in our pets as they do in us.  By decreasing the release of inflammatory mediators, antihistamines help alleviate the symptoms of allergies.  As is the case with people, different antihistamines will affect our pets in different ways.  Some pets will become sleepy, others may become excitable, and some may show a decrease in appetite.  Despite these few side effects, antihistamines are relatively safe to use on a daily basis and are most effective when given prior to and regularly through the allergy season. The biggest benefit to using these medications is that it allows us to avoid using steroids or allows us to use a lower dose of steroids.    

FATTY ACIDS:  Fatty acids are compounds in the body that are used as building blocks to form compounds such as histamine and prostaglandins.  Histamines are compounds that can cause inflammation and allergies.  Supplementing the diet with a non body source of fatty acids may actually help decrease the amount of inflammatory mediators produced by the body because the oral fatty acid gets metabolized into different, less potent inflammatory mediators. Fatty acid supplements work in about 30 % of our patients. It is believed that some antihistamines and fatty acids work synergistically to achieve an even greater effect.  Fatty acids also help moisturize and improve the condition of the hair coat which is important in our allergy patients.

STEROIDS: Steroids are used when the above therapies are not effective or the allergies are so severe that the patient needs relief.  Steroids are often used to help a patient survive through allergy season until allergy testing and desensitization therapy can be initiated. Steroids basically turn off the over-reactive immune system. Steroids do have side effects some of which can be serious. The most common side effects are increased thirst and urination, increased appetite and weight gain.  Steroids also predispose pets to infections, especially bladder infections. Steroids can also interfere with your pet’s own hormonal regulation. There are short acting and long acting steroids. The severity of side effects is directly related to the potency of the steroid used.  There are two basic forms of steroids. There is an injectable form and a pill form.  The injectable form can last in your pet’s system for 2 to 3 months. The tablet form usually lasts for about a day.  It is safer for your pet to be on the oral tablets at a graduated, tapered dose.  The injectable form is used when your pet’s allergies are so severe that immediate relief is needed.  Steroid treatment is a serious therapy that requires close attention by your veterinarian.    

ALLERGY TESTING & DESENSITIZATION THERAPY:  This is the gold standard for a patient with allergic dermatitis.  Your pet may either be skin tested or have blood drawn for an allergy test.  The skin test involves injecting diluted allergens into your pet’s skin and looking for a flare skin reaction.  The blood test is done in a specialized laboratory. The test looks for blood levels of IgE in response to antigens. Most allergy testing is done in the winter when your pet is no longer receiving medications. Once it is determined what your pet is allergic to, an allergen-specific immune serum can be compounded.  This serum will have low levels of antigen that your pet will be exposed to by injections over a period of time – in effect desensitizing your pet to the allergens.  The exact mechanism of action of immunotherapy is still unknown in the dog but it is postulated that immunotherapy decreases the levels of IgE antibodies and increases the levels of IgG antibodies along with altering T-helper cell response.  Overall, desensitization improves allergy symptoms in about 50% of patients and the results can be very gratifying.

CYCLOSPORINE THERAPY:  Cyclosporine is a chemotherapy drug. It has been altered and formulated into a low dose oral tablet called Atopica. Atopica is a potent immunosuppressor of T- helper cells and inhibits interleukin -2 which is an inflammatory mediator. These two actions help turn off the over reactive immune system response and provide relief for the allergy pet.  Atopica does not suppress cell- mediated immune responses and therefore overall doesn’t adversely affect the pet’s ability to fight infections.  It is only approved for use it dogs.  If you would like to read more about this newer medication, please visit the web site at www.us.atopica.com.

DON’T FORGET ABOUT FLEAS:
No amount of allergy treatment in the world will relieve your pet’s itching if your pet has fleas.  As stated earlier, 80% of our pets with allergies are also allergic to fleas.  It may take only one or two flea bites to cause an allergic reaction in your pet.  One flea is one flea too many for a pet with allergies.  Flea control is essential for an allergy patient.

To read the first of these two articles - click here