Allergies

It is estimated that at least one in five dogs in the United States suffers from some sort of allergy. That number may be on the rise. This article will discuss the signs, diagnosis, and treatment of allergic conditions in pets.

What animals are typically affected by allergies? For the most part, allergies will tend to develop in the early years of a pet's life. 85% of all allergic animals are first diagnosed when they are under 3 years old. Studies have determined that
many allergies are inherited. There are many breeds that have demonstrated a strong breed predisposition for allergies. Some of these breeds include Terriers, Irish Setters, Beagles, English Setters, Lhasa Apsos, Pugs, Labs, and Miniature Schnauzers. Other breeds not mentioned here, as well as mixed breeds, can also have problems with allergies. Neither sex is more affected by allergies than the other. 

What are the signs of allergies? When most people think about the signs and symptoms of allergies they think about runny eyes, a stuffy nose, and sneezing. While these things can all happen in animals, they are NOT the typical signs associated with allergies. The most common manifestation of allergies in pets is itching and scratching. As a result of this itching and scratching animals may have reddened or thickened skin, hair loss, and scabs or crusts. Animals that have problems with allergies may also lick or chew excessively at their feet. In white animals, this can cause a brownish discoloration of the hair on the paws. The most common areas affected include the head, face, ears, base of the tail, and feet or paws. In severe cases, the signs may be generalized or all over the animal's body. Allergic animals may demonstrate signs at certain times of the year or throughout the whole year, depending on what they are allergic to.

What are some of the things animals are allergic to? Animals can be allergic to almost anything, inhaled, ingested, or contacted, including but not limited to pollens, molds, grasses, weeds, trees, and foods. Flea allergy is the most common allergy seen in pets. The bite of one flea is enough to start an allergic animal itching and scratching.

How are allergies in pets diagnosed?
1. History and physical exam. While certain information on frequency and location of itching and scratching and the general appearance of an affected animal can suggest an allergy problem, this alone CANNOT diagnose an allergy. This is because there are many other conditions that can cause skin problems that may appear to be allergies. Some of these conditions include external parasite problems, fungal infections, autoimmune disease, and bacterial infections.

2. Preliminary testing. In order to assure that your pet does not have an underlying condition that is causing allergy-like signs and symptoms, it may be necessary to perform some simple tests. A skin scrape may be done to look for sarcoptic mange or demodex. These are two external parasites that can cause hair loss and itching. A fungal culture may be done to determine that your pet is not suffering from an external fungal infection. Skin cytology may confirm the presence of a primary or secondary yeast or bacterial infection. A skin biopsy may be done to determine how the animal's skin is reacting at a microscopic level. It will also determine if your pet is suffering from pemphigus, a disease in which the body's immune system "attacks" the skin. If these tests are all negative, other tests may be done to determine what your pet is allergic to.

3. Allergy testing. There are two options for definitively determining what your pet is allergic to. The first is intradermal skin testing. With this method, your pet is sedated and some hair is clipped. A small injection of each of the items being tested
will be injected into the skin. After a designated amount of time, the veterinarian will look at the reaction, if any, that the animal had to the item injected. The second option is serology. With this method, a blood sample will be drawn from your pet. This blood will be sent off to a lab that will use the blood to determine what items your pet is allergic to. 

4. Diet trial. Since intradermal skin testing and serology cannot accurately determine if an animal is allergic to a certain food component, a diet trial may be done. In a diet trial, the animal will be switched to a food with a new protein source. The most common protein sources that cause problems in dogs and cats include beef, chicken, turkey, corn, soy, wheat, and egg, among others. Thus, the special diet must not contain these components. If the signs resolve while on the special diet and reoccur when the original diet is fed, a food allergy can be suspected. In some instances, multiple food trials may be necessary.