Is your cat grooming half her hair off or your dog licking his paws raw?It may well be your pet is experiencing allergies, one of the mostcommon health problems for pets. Just like people, animals haveallergic reactions because their immune system--the system thatprotects the body from foreign and potentially infectioussubstances--overreacts to some material. Almost anything--pollen, dust,an ingredient in pet food, a household chemical, an insect bite--canset off an alarm in the immune system, causing it to pump out largeamounts of white blood cells, hormones, and other material calledhistamines into the bloodstream. The result for animals can be a rangeof different effects, including itchy, swollen skin--known aspruritis--difficulty breathing, or a disruption of the digestive tractsuch as vomiting or diarrhea. These symptoms are the animal equivalentof a person's sneezing, runny nose, and watery eyes.

Pets with these kinds of allergic symptoms can be pretty miserablecreatures, and unfortunately they can't be cured. Allergies arelife-long, chronic problems. The good news is that there's a lot youcan do to help your animal "children" feel better. The best way tostart is to find out what your pet is allergic to, so you can keep theallergen out of his environment. Animal allergies generally fall underone of four main categories.

Contact allergies

These are the least common type of allergy in animals. They happen whenan animal's skin comes in contact with the material he's allergicto--if he rubs his face against a wool blanket, for example, and he'sallergic to wool. The chemicals in flea collars can cause this problemas well. The skin at the point of contact will be irritated--it mayitch, become thickened or discolored, have a strong odor, and/or losehair due to constant biting or scratching. Contact allergies aregenerally not a hard problem to solve--they're usually confined to aspecific area of an animal's body, and the allergen shouldn't take toomuch work to discover. You can try removing different materials thatyour pet touches until you find the one that irritates his skin.

Food allergies

Diet can be a complicated factor in pet allergies. Most animals are notborn with allergies to food; their immune systems develop an allergicresponse over time to some part of their diet, often one of the animalproteins. A food allergy can present in a lot of different ways,including the itching, digestive disorders, and respiratory distressalready mentioned. They can be a real challenge to solve, however. Youcan try to figure out what's causing your pet's allergic reaction byfeeding him different diets, but the allergic effects of food can stayin the system for eight weeks. You may have to keep your furry friendon a special hypoallergenic (non-allergy-causing) diet for eight totwelve weeks to see how he reacts, and you may have to do it severaltimes with several different diets before you find one that doesn'tcause an allergic reaction. And while you're feeding these test diets,you'll have to make very sure that your pet doesn't eat any treats,vitamins, leftovers or scraps, or even plants around the house. He hasto eat the test diet exclusively for the entire eight to twelve weeksto determine whether he has an allergic reaction to it.

Inhalant allergy

Inhalant allergies are the kind we humans are most used to. Just likeus, our pets get hay fever, meaning they can be allergic to the pollenand mold that fills the outside air during the spring and fall. Theycan also be allergic to the dust mites, mildew, and mold that can beinside every home. These kinds of allergens usually produce severeitching in pets, which is usually concentrated in the ears, feet,groin, and armpits, though it can be spread across the entire body.Dogs in particular may develop hairless, irritated "hot spots" fromconstantly chewing on and scratching the affected skin.

Most animals that are allergic to airborne particles are usuallyallergic to more than one. Often, they will only experience itchingduring the pollen-heavy seasons of the year, just like humans with hayfever. If you find that your pet's allergies seem to be seasonal, youmay be able to limit his outdoor time during allergy season. Your petmay be reacting to an indoor allergen, however, or an allergen thatdoesn't vary by season. In that case, there's not much you can do tokeep him away from whatever he's allergic to, though an air filtermight provide some relief.

Flea allergies

This is an extremely common problem for pets, possibly the most commonallergy of all. Animals aren't actually allergic to the fleasthemselves, but to proteins that fleas secrete in their saliva whenthey bite. Your pet doesn't have to be a walking flea circus to sufferfrom an allergy, either. Affected animals can itch severely from asingle bite for over five days! So, if you suspect your pet is allergicto fleas, you're going to have to work very hard to keep the littlepests away. Frequent baths are a good idea, as are the prescriptionflea applications and pills. Consult your veterinarian when you chose aflea repellent for your pet, though; the wrong kind or too strong of aconcentration could cause irritated skin, seizures, and even death inextreme cases. You will also want to treat your pet's environment,including any bedding or carpeting he comes in contact with.

Other Options

What makes allergies hard to deal with is that in many cases, youeither won't be able to determine exactly what is causing the reactionor won't be able to remove it from your pet's environment. This iswhere your veterinarian comes into the picture. You and yourveterinarian will probably have to work together to determine the besttreatment, or combination of treatments, for your pet's allergy. Youmay have to go through a series of trying a possible solution, waitingto see how your pet reacts to it, and moving on to another solution.

Your veterinarian may suggest one or more of the following things:

Testing--Yourveterinarian has a few different tools to help determine the source ofyour pet's allergy. Intradermal or "scratch" tests involve making smallabrasions in an animal's skin and inserting small amounts of materialsthat the veterinarian suspects the pet might be allergic to. If theanimal is allergic to one of the materials, say dust mites or ragweedpollen, the immune system will react to it and that particular scratchwill become inflamed. There are also a number of blood tests yourveterinarian can use to analyze the amount of certain chemicals thatthe immune system releases into the bloodstream when exposed todifferent allergens. These tests can be used to tell whether your petis having an allergic reaction or whether the problem is caused bysomething else, and sometimes they can determine the source of theallergy.

Steroids--Thesedrugs work to suppress the immune system and make the allergic reactionless severe. Steroid treatment can help your pet even if you can'tdetermine what he's allergic to or how he's being exposed. They canhave several side effects, however, and they affect nearly every organin the body. Steroid use can cause weight gain, increased thirst andurination, and increased aggression and other behavioral changes. Theyare generally used if the allergy occurs for a short amount of time,because long-term use makes animals more prone to infection, as well assusceptible to diabetes and seizures.

Immunotherapy--Thisis one of the safest and most effective ways to treat allergies, but italso takes the longest amount of time to work. In immunotherapy,animals are given regulary--often weekly--vaccinations that containsmall amounts of the substance they're allergic to. The same therapy isused for people who go in for allergy shots. It gradually desensitizesthe immune system to the allergen, meaning that as time goes by, theimmune system is reprogrammed and doesn't react to the allergen asstrongly. Unfortunately, it takes some time for the immune system toreadjust. It can sometimes be six to twelve months before animals showany improvement from the treatment.

Antihistamines--Thesedrugs, much like the allergy medication people take, work to block thechemicals released by the immune system, called histamines. They areeffective at reducing itching and inflammation, and they are relativelysafe to use. Their major drawback is that they cause sedation, and canmake pets extremely drowsy and sluggish. Occasionally, they can changean animal's energy level enough to affect his quality of life.

Symptomatic treatment--Evenif none of the above treatments are effective, you can still give yourpet a lot of relief by simply treating his symptoms as they come up.There are a number of soothing shampoos on the market that containingredients like oatmeal or Epsom salts. Your veterinarian may also beable to suggest ointments, ear treatments, or sprays that can make yourpet more comfortable. Be cautious about using home remedies or herbaltreatments on your pet, however. Consult with your veterinarian beforetrying any new treatment, because you could damage your pet's skin oraggravate the allergic reaction. Most of all, remember that while youcan give these symptomatic treatments often, they will only providetemporary relief. If your pet still seems uncomfortable despite thebaths or other treatments, you can talk to your veterinarian aboutlong-term treatment.

Whatever treatment decision you and your veterinarian come to, restassured that the patience and determination it can take to treatallergies is well worth it. Though it may take some time and effort,you can help your itchy, grouchy pet feel comfortable again.

Copyright © 2008, American Animal Hospital Association

Reprinted with permission from the American Animal Hospital Association.