The number of dogs with allergies has increased dramatically in recent years.
It is now estimated that one in seven dogs suffer from allergic symptoms.
According to Veterinary Pet Insurance, skin
allergies are now the most common reason dog owners take their dog to the
veterinarian. Heredity plays a role. Although certain breeds appear to be more
allergy prone, all breeds and their mixes can be affected.
An allergy is in an unpleasant reaction caused by exposure to a food,
inhalant, or something in the dog’s environment. What the dog is exposed to is
called the allergen. The way in which the dog’s immune system responds to the
allergen is the allergic or hypersensitivity reaction.
Before a dog can have an allergic reaction, she must be exposed to the
allergen at least twice. The first exposure causes the immune system to
manufacture antibodies to the allergen. A later exposure triggers an
allergen-antibody reaction that releases histamine, the chemical mediator
responsible for the reaction.
While humans tend to experience upper respiratory symptoms when an allergy
is triggered, the target organ in dogs is usually the skin, with intense itching being the principal
sign. Dogs with allergies often scratch continuously and are miserable,
snappish, and generally unpleasant to be around.
There are two kinds of hypersensitivity. The immediate type occurs minutes
after exposure and usually produces hives. The delayed response occurs hours or
days later and causes intense itching. Anaphylactic shock is a severe hypersensitivity
reaction of the immediate type, accompanied by diarrhea, vomiting, weakness, difficulty breathing with stridor,
collapse, and, if untreated, death.
Canine allergies fall into four categories:
Those caused by fleas and other biting insects (flea allergy
Those caused by inhaled allergens such as dust mites, grasses, molds, and
tree and weed pollens (canine
Hives are an allergic reaction characterized by the sudden appearance of
raised, circular, itchy wheals on the skin of the face and elsewhere. The hair
sticks out in little patches. Frequently, the eyelids will also swell. Hives generally appear within
30 minutes of exposure and disappear within 24 hours.
Insect bites are a common cause of hives. Hives can occur after a
vaccination. Penicillin, tetracycline, and other antibiotics can produce hives. Topical insecticides and
soaps are other causes. Hives that come and go usually are caused by an
allergen in the dog’s environment.
Treatment: When possible, identify the allergen and prevent further
exposure. When a food allergy is suspected, modify the dog’s diet. When hives
appear shortly after a shampoo or application of a topical insecticide, bathe
the dog and rinse thoroughly to remove the chemical from the dog’s coat and
Hives usually respond well to an antihistamine such as Benadryl. Cortisone may be needed to
control a severe case. Consult your veterinarian.