20/Jan/2008
Your Pet’s Health Protecting Your Cat or Dog from Dangerous Food Allergies
By Dr. Tony LoBue
Crossroads Animal Hospital
Editor’s note: In our last issue, Dr. LoBue covered pet inhalant allergies. Here, he discusses food allergies and how to protect your pet from them.
Food allergy is one of the itchiest conditions known to cat and dog. Animals eat a variety of processed food proteins, fillers and colorings which are further processed inside their bodies. Proteins may be combined or changed into substances recognized by the immune system as foreign invaders to be attacked. Adverse reactions to food can be manifested by skin, respiratory, gastrointestinal and neurological signs.
In dogs and cats, the skin and GI tract seems to be the most common systems affected. Approximately 10 to 15 percent of food-allergic animals with skin signs will have GI disease concurrently. Other concurrent allergic dermatitis occurs 20 to 30 percent.
Many owners assume itching due to a food allergy requires a recent diet change of some sort. In fact, the opposite is true. Food allergy requires time to develop. Most animals have been eating the offending food for years with no trouble.
Clinical signs can mimic those of canine atopy Part I. The most common symptoms of a food allergy are itching, licking or chewing. Otitis Externa (ear infection) along with other skin problems are also common in conjunction with food hypersensitivity. Some pets may also have diarrhea and other digestive problems. Symptoms can appear at any age, whether a pet has just started a new diet or has been eating the same food for several years. In a recent study, ear problems and feet licking were the highest areas involved in food allergy.
Diagnosis
Other common diseases like scabies, ringworm, demodex, atopy, flea allergy and any secondary skin problems need to be ruled. After ruling out the other diseases the diagnostic test of choice for food allergy is an elimination diet.
Diagnosis and management of food allergy in the dog has been made easier in recent years because of new unique protein/limited ingredient diets available in most veterinary clinics. The length of the diet trial needs to be 10 to 12 weeks. Studies have shown that some dogs may not show significant improvement on their diet trial until 10 to 12 weeks into the food trial.
In addition, the patient should be placed on non-chewable, non-flavored heartworm prevention for the length of the diet trial. The patient should be allowed no other treats, chew toys, raw hides etc. Cheating on the diet by giving treats, animal eating garbage, or scavenging under the high chair can occur. Also, it is recommended to give distilled water during the food trial. It is doubtful that a dog that is experiencing no change in clinical signs at eight – nine weeks will improve dramatically after that time. Diets containing fish, lamb, duck, venison, rabbit, kangaroo, modified soy, modified chicken livers etc., as the protein source are all commercially available. Lamb and rice diets ten years ago were a good hypoallergy diet but are not at this time.
Therapy
The only therapy is to avoid the allergen. Many owners will elect to continue on the “food trial” commercial diet. If they do not wish to pinpoint the individual allergen, they should be encouraged to keep a list of the food substances that have been previously fed to their pet. With this information, if they desire to change diets or if the diet being fed becomes unavailable, they may be able to choose another commercially available diet that avoids proteins from the “potentially offending protein” list.
.
By Dr. Tony LoBue
Crossroads Animal Hospital
Editor’s note: In our last issue, Dr. LoBue covered pet inhalant allergies. Here, he discusses food allergies and how to protect your pet from them.
Food allergy is one of the itchiest conditions known to cat and dog. Animals eat a variety of processed food proteins, fillers and colorings which are further processed inside their bodies. Proteins may be combined or changed into substances recognized by the immune system as foreign invaders to be attacked. Adverse reactions to food can be manifested by skin, respiratory, gastrointestinal and neurological signs.
In dogs and cats, the skin and GI tract seems to be the most common systems affected. Approximately 10 to 15 percent of food-allergic animals with skin signs will have GI disease concurrently. Other concurrent allergic dermatitis occurs 20 to 30 percent.
Many owners assume itching due to a food allergy requires a recent diet change of some sort. In fact, the opposite is true. Food allergy requires time to develop. Most animals have been eating the offending food for years with no trouble.
Clinical signs can mimic those of canine atopy Part I. The most common symptoms of a food allergy are itching, licking or chewing. Otitis Externa (ear infection) along with other skin problems are also common in conjunction with food hypersensitivity. Some pets may also have diarrhea and other digestive problems. Symptoms can appear at any age, whether a pet has just started a new diet or has been eating the same food for several years. In a recent study, ear problems and feet licking were the highest areas involved in food allergy.
Diagnosis
Other common diseases like scabies, ringworm, demodex, atopy, flea allergy and any secondary skin problems need to be ruled. After ruling out the other diseases the diagnostic test of choice for food allergy is an elimination diet.
Diagnosis and management of food allergy in the dog has been made easier in recent years because of new unique protein/limited ingredient diets available in most veterinary clinics. The length of the diet trial needs to be 10 to 12 weeks. Studies have shown that some dogs may not show significant improvement on their diet trial until 10 to 12 weeks into the food trial.
In addition, the patient should be placed on non-chewable, non-flavored heartworm prevention for the length of the diet trial. The patient should be allowed no other treats, chew toys, raw hides etc. Cheating on the diet by giving treats, animal eating garbage, or scavenging under the high chair can occur. Also, it is recommended to give distilled water during the food trial. It is doubtful that a dog that is experiencing no change in clinical signs at eight – nine weeks will improve dramatically after that time. Diets containing fish, lamb, duck, venison, rabbit, kangaroo, modified soy, modified chicken livers etc., as the protein source are all commercially available. Lamb and rice diets ten years ago were a good hypoallergy diet but are not at this time.
Therapy
The only therapy is to avoid the allergen. Many owners will elect to continue on the “food trial” commercial diet. If they do not wish to pinpoint the individual allergen, they should be encouraged to keep a list of the food substances that have been previously fed to their pet. With this information, if they desire to change diets or if the diet being fed becomes unavailable, they may be able to choose another commercially available diet that avoids proteins from the “potentially offending protein” list.
.
