Treating Allergies in Pets, Pet Food

by Food and Drug Administration (FDA)

(Page 3 of 3)

Treating Allergies in Pets

Although allergies can't be cured, they can be controlled by avoiding the allergens, treating the symptoms, or desensitizing the pet. In Nora's case, all three methods are used.

Fleas, food ingredients, and some substances that trigger contact allergies may be avoidable, but "with atopic allergies, avoidance is virtually impossible," says Jeffers.

Drug products are available to relieve the symptoms of itchiness and inflammation in pets. Like any drugs designed for animals, these products must obtain FDA approval before they can be marketed by meeting rigorous scientific standards similar to those for human drugs.

The FDA approved two itch-relieving drugs in 2003: Atopica (cyclosporine) for controlling atopic dermatitis in dogs weighing at least four pounds, and Genesis Topical Spray (triamcinolone) for controlling itching related to allergic dermatitis in dogs. Atopica, a product of Novartis Animal Health US Inc. of Greensboro, N.C., is a capsule given orally. It works by inhibiting specific immune cells from reacting to allergens, and can be given as a lifelong treatment. Genesis, made by RMS Laboratories Inc. of Vidalia, Ga., is a steroid spray that is applied to a dog's skin for up to 28 days. Both of these drugs must be prescribed by a veterinarian.

The FDA has approved other steroid products for short-term use in dogs and cats to relieve inflammation and itching. Long-term steroid use is discouraged because these drugs work by suppressing the immune system; this suppressant action over time can leave an animal vulnerable to infection, diabetes, and other conditions.

Veterinarians often prescribe antihistamines approved by the FDA for humans to relieve itchiness in pets. Under the Animal Medicinal Drug Use Clarification Act of 1994 (AMDUCA), veterinarians may legally treat dogs and cats with drugs that have been approved for people but not for animals. Pet owners should check with their veterinarians before giving a pet any human medications, including over-the-counter antihistamines.

"If we can control the allergies through medication for occasional flare-ups, antihistamines and steroids are useful," says Troutman. But if these medications are needed continuously to provide relief, Troutman recommends seeking other options, such as immunotherapy.

Immunotherapy is a treatment that stimulates the immune system to decrease the body's reaction to allergens. Similar to people with allergies, animals can be given immunotherapy, or desensitization injections. These "allergy shots" contain small amounts, or extracts, of the substances that the animal is allergic to, based on the results of skin testing. The owner gives the shots to the pet at home, usually in the scruff of the neck. The extracts used for allergy testing and treatment in veterinary practices are licensed by the U.S. Department of Agriculture's Center for Veterinary Biologics.

Somewhere between 50 percent and 70 percent of dogs and 75 percent to 80 percent of cats respond to immunotherapy, depending upon the study reported, says Morris. "Occasionally, it is so effective that the animal is normal without other treatments," he says, but the majority require medications in addition to the injections. The injections are usually given every 7 to 21 days, depending on the pet's response, says Morris. And rarely does an animal become permanently desensitized so that the injections can be stopped.

Nora gets a weekly injection. Mathews also gives her Atopica and, when the pollen count is up, an over-the-counter antihistamine. Mathews has placed synthetic blankets around the house for Nora to lie on, since the dog is allergic to cotton and wool in the furniture and carpeting. Nora also has a vinyl bed to lie on in the yard, since she's allergic to grass. This allergy management program helps keep the 18-month-old dog comfortable. "She still has periods of scratching," says Mathews, but "she's not biting herself as much and she's sleeping at night." Mathews reports that her other dog, Nora's littermate Nick, is allergy-free.

Allergies in pets are neither preventable nor foreseeable, says Morris. "You can have one puppy out of a litter of 10 with allergic skin disease, or it can skip generations. We can't possibly predict it," he says, even if you have a pet examined by a vet at a very young age.

Pet Food: To Switch or Not to Switch?

Most experts agree that changing foods periodically will not keep a pet from becoming allergic to certain ingredients.

"If you're genetically predisposed to develop an allergy to something you eat, it will occur," regardless of switching foods periodically, says Daniel O. Morris, D.V.M., chief of staff of the veterinary hospital at the University of Pennsylvania in Philadelphia.

Morris advises against changing food ingredients at least for the first year or two of a pet's life. "I see dogs, especially, developing food allergies at very early ages," he says, adding that it's not a good idea to expose young animals to many different ingredients.

"The gut lining in the intestinal tract is not fully formed," says Morris. "The theory is that it allows food proteins larger than appropriate to be absorbed." These food proteins react with the immune system, causing an allergic response.

If you know your pet has allergies to certain food ingredients, read the food label carefully to avoid those ingredients, Morris says. The front of a can or bag of food may state one or two main ingredients, but the label will list a number of others as well. "Changing brands does not necessarily mean you're changing ingredients," he adds.

About the Author

www.fda.gov
FDA is A United States government body that oversees medical devices, including contact lenses, intraocular lenses, excimer lasers and eyedrops. In the US, these products must be approved by the FDA before they can be marketed.