Originally appeared as Ask the Vet by Dr. Shawn Ashley in Pug Talk Magazine (Nov/Dec/92 issue)
Allergies arise due to the body's immune system overreacting to a certain stimulus (antigen/allergen). In people the major scenario is that of hay fever. In dogs allergies can also manifest themselves as itchy skin, red, inflamed ears and gingiva. This is because animals have more histamine releasing cells in these areas than do humans.
The most common cause of allergic based skin problems (dermatitis) in dogs is external parasites - -FLEAS! In some dogs one flea bite can bring on a raging dermatitis usually focused around the tail/head region. Other causes are internal parasites, contact allergies (carpet cleaners, floor wax, cedar bedding, grass), food (beef, chicken), and inhaled allergens (poliens, smoke, etc.). As in people finding the cause is the only true way to treat an allergy.
Once identified, treatment can consist of avoidance in cases of contact or food allergens or immunotherapy when dealing with inhaled allergic-atopic conditions.
However, if through trial and error a suspicion to a certain cause can be detected (ie: fleas in the summer, pollen in the fall) symptoms can be managed by a COMBINATION of antihistamines, low-dose cortisone, fatty acid supplementation, antibiotics for skin infections, and medicated shampoo regimens that change as the dog's condition changes.
It must be noted these only manage the symptoms. They do not cure until the specific cause has been identified and dealt with. In the past dogs were often placed on cortisone to stop the itching without regards to long term effects. Longterm cortisone can suppress the immune system with can lead to increase susceptibility to infection --with respect to the skin, these infections can cause more itching and scratching and a vicious cycle ensues with a miserable dog and an unhappy owner being the end result.
Therefore, a combination of topical and medical methodology must be pursued. If these methods do not work allergy testing should be considered over raising cortisone dosages. There is no inexpensive easy quick fix to combat allergies, but our understanding of the antigen/allergin problem is growing rapidly. This knowledge has led to many new products to aid in this battle.
Shampoos now on the market consist of solubilized coal tar products (they no longer took and smell like something dead!) that aid in controlling superficial skin infections and seborrhoea. If there is no longer an infection a hypoallergenic shampoo should be used over the more drying medicated shampoo. If the skin is dry and flaky, fatty acid supplementation either topically or orally is the most effective way to add needed oils back into the skin.
When used long term they also provide natural antihistamine effects and can noticeable decrease the amount of cortisone needed to control allergic pruritus. Hypoallergenic diets usually consisting of lamb and rice often prove beneficial during allergic episodes or may be used in dispelling a food allergy.
Other products have been developed to aid in soothing inflamed, reddened allergic skin! Oatmeal shampoos, creme rinses, and colloidal bath treatments, newer antihistamines, and even new oatmeal shampoos with antihistamines in them!
If a combination of these products is found not to help, it is recommended to wean off all cortisone for at least eight weeks and then pursue intradermal allergy testing and subsequent immunotherapy, which usually means weekly allergy shots directed towards desensitizing the body to culprit antigens.