Understanding Canine Allergies

    Published: 06-16-2009
    Views: 11,701
    Nancy Kerns, editor of the Whole Dog Journal, discusses what to do about canine allergies.

    Nancy Kerns: Hi! I am Nancy Kerns, Editor of the Whole God Journal. Did you know that when dogs have allergies the number one symptom is intense itching? A dog suffering from an acute allergy attack may lick or chew himself obsessively. Lick his paws repeatedly or shake his head constantly as if he's got a serious ear infection.

    Over a lifetime chronic allergies can make the dog irritable and depleted with low-level infections constantly breaking out on their skin, feet and in their ears, worn front teeth from chewing themselves, and smelly sparse coats. Chronic allergies can also deplete an owner's time and money, especially if the owner fails to take effective action.

    An allergy is the result of an immune system gone awry. When it's functioning properly, the immune system patrols the body checking the identification of every molecule. It allows the body's own molecules and harmless foreign substances to go about their business, but detects, recognizes and attacks potentially harmful agents such as viruses and pathogenic bacteria.

    But when a dog develops an allergy the immune system becomes hypersensitive and malfunctions. It may mistake benign agents such as pollen, dust or food for harmful ones and sound the alarm calling in all the body's defenses in a misguided one-sided battle that ultimately harms the body's tissues or disrupts it's usual tasks. Alternately if the immune system may fail to recognize agents of the body itself and start to wage a biochemical war against itself.

    The three most common types of canine allergy are flea bite hypersensitivity, also called flea allergy. About 40% of all dogs are hypersensitive to flea bites. Atopy, also known as atopic disease or atopic dermatitis which is analogous to hay fever in humans, dogs with atopy may be allergic to pollen, mold spores, dust, dust mite droppings, and other common environmental antigens.

    Dogs maybe exposed through breathing them in or through the skin. It's generally accepted that 10% to 15% of all dogs have atopy. About 80% of atopic dogs also display flea bite hypersensitivity.

    The third major type of canine allergy is food hypersensitivity, but this is much less common than many dog owners believe. Some experts estimate the prevalence of food allergy and dogs at only 1% to 5%. Other sources suggest a figure as high as 10%. However, almost half of dogs who suffer from food allergy also exhibit other hypersensitivities complicating the diagnostic picture.

    Clinical signs of food allergy are extremely variable. The skin, gastrointestinal tract, respiratory tract, central nervous system and any combination of these maybe affected, the skin however is the most frequently involved.

    Non-seasonal generalized itchiness is the most common sign. About 10% to 15% of food allergic dogs with dermatologic symptoms also suffer from gastrointestinal symptoms including diarrhea, vomiting, gassiness and cramping.

    Food hypersensitivity can begin at any age even late in a dog's life. Allergies that start in puppies younger than six months old are most likely caused by food. Remember, by definition this condition is characterized by an abnormal immunological response to food. Don't confuse this with food intolerance which is an abnormal, but non-immunological response to some foods. Dogs with food intolerance are far more likely to suffer digestive problems such as vomiting, diarrhea and gas.

    There are many medical causes of itching. Your veterinarian will need to thoroughly examine your dog, take a good history and perhaps run some tests to rule out the non-immunological causes of itching.