Allergies are sometimes a case of your dog's immune system and defenses getting the wrong signals. They represent a reaction of your dog's body against foreign substances that may or may not actually be a real threat to your dog's health. Allergic reactions can be immediate or delayed. Some reactions only occur after multiple exposures to the offending substance. Along with food and inhalant allergies, many dogs show allergic reactions to insect bites. This includes the arch nemesis the flea as well as other bugs such as mosquitoes and black flies. Check out Chapter 12 for information on parasite problems.

Food Allergies

Some dogs have food allergies. These allergies can be to unusual foods or to foods that most people would consider normal dog food. Remember that although they are classified as carnivores, dogs are omnivorous in their eating habits, generally eating a wide range of food types with no problems. Still, some dogs may have allergies to normal dietary proteins. For example, some dogs are allergic to beef. For these dogs, the proteins in the meat stimulate allergic skin reactions. Up to 15 percent of all allergic skin disease in dogs may be caused by food allergies, the third most common itchy skin disorder.

Most dogs with food allergies will show skin signs, such as inflamed ears and skin problems in the groin area. You may see them rubbing their faces or chewing their feet. It is now believed that at least some cases of inflammatory bowel disease (manifested by primarily by diarrhea) are also caused by food allergies.

Treating Food Allergies

A dog with food allergies will need a period of limited protein-and-carbohydrate diet to determine what foods are safe and must then be kept on that diet very strictly. (That means treats have to be considered, too.) There are special diets with very limited and unusual sources of protein and carbohydrates that can be used for testing and possibly for lifelong maintenance of your dog. Some dogs will eventually become allergic to these new sources of nutrition as well and require more dietary changes.

A novel approach to food allergies is to reduce proteins to very small components. These components are very easily absorbed and utilized and appear less problematic for dogs. This type of protein-reduced food can only be prescribed by a veterinarian.

Inhaled Allergies

Inhalant allergy sometimes called atopy is a reaction to substances in the environment like dust or pollen. Humans with inhalant allergies tend to sneeze, wheeze, and have a runny nose. Dogs most commonly show their inhaled allergies by breaking out with skin problems. These allergies tend to start out as seasonal problems. When the pollen counts are high, you sneeze and your dog scratches. Wiping your dog off in the evening with an unscented dryer sheet may remove some of the offending pollens. Following the guidelines for human sufferers helps as well — these include using air conditioning and staying indoors with the windows closed on days when mold and pollen counts are high.

Treating Inhaled Allergies

Mild cases may be controlled by short-term medications such as antihistamines or corticosteroids, but in the long run your dog may do best with a desensitization program. With this therapy, your veterinarian will do a skin test on your dog by injecting small amounts of allergens under the skin. Offending allergens cause red bumps or wheals. Once the problem allergens have been identified, small amounts of those allergens will be specially mixed for your dog. A schedule of allergen injections will gradually accustom her body to these substances. The strength of the injections increases with time, and the time between injections also increases. Many dogs do very well on this type of program.