Pet Allergies

by Morris Nejat, MD

When it comes to pet allergies, man's best friends may often be his worst enemies. Numerous times a day, I come across patients who end up being allergic to a favorite animal or are concerned that they may be allergic to their pet. Before you start pointing fingers at the dog for a family member's allergy symptoms, you must be sure not to wrongfully accuse an innocent pet.

Diagnosis of Animal Allergy

The only way to be certain of an allergy is by undergoing a specific test. In my practice, I start by asking you questions about your symptoms, history of allergy, exposure, family history, etc., to get a good picture of your situation and to see what I can do to help you. To help determine whether an allergy is involved, I usually perform a skin-prick test or intracutaneous test. These tests involve either a gentle prick through a drop of allergen extract on the surface of your arm or the injection of a small amount of allergen extract into the skin. This may result in some swelling and reddening of the skin, which suggest that you have an allergy.

On the other hand, if skin testing is negative, the animal in question may not be the culprit and the investigation into other sources of allergy are on the chopping block. Too often I have seen a family get rid of a loved family pet without adequate confirmation – only to find out down the road that they were wrong and it wasn't Fluffy or Rover making little Johnny wheeze, but rather, his teddy bear.

Treatment of an Animal Allergy

Now that you have been diagnosed with an animal allergy, it's important to understand what aspect of the animal you are allergic to. Below is a list of common animal allergies and what is best to do about each individual animal allergy:

Cat Allergy:

Patients allergic to cats are actually allergic to the cat's saliva. You might be thinking to yourself that you don't tend to get slobbery, wet kisses from your cat – wrong animal. However, typical allergic symptoms are not as a result of direct contact with the cat's saliva. Instead, when the cat grooms itself by licking its fur and skin, it deposits its saliva on the fur. The saliva dries, leaving behind the protein antigen that is the source of allergy to cats. These allergens (cat saliva antigens) are very lightweight and are easily aerosolized. Once airborne, the antigen can spread to clothes, furniture, carpeting, or any other household item.

Once cat allergy is confirmed, the best way to decrease allergy symptoms is to remove the cat from the home. Note that relatively high concentrations of cat antigen can remain, even months after the cat is removed. Thereby, it is important to clean or replace the carpeting, furniture, and all other material that may harbor the cat saliva antigen.

If you decide to keep the cat; however, you should at least try to keep the cat out of the bedroom or off of the bed. Washing the cat weekly can also help reduce the cat allergen load in the house.

The great news for your four-legged friend is that there are less dramatic means to improve or eliminate cat allergy symptoms other than getting rid of your pet; these means include the use of medications and allergy immunization.

Dog Allergy:

 Patients allergic to dogs are allergic to the dog's saliva. As with cats, dogs groom themselves by licking their fur and skin, depositing dog saliva antigens that also become airborne when dry, and spread to clothes, furniture, carpeting, etc. Allergy to dogs is not as problematic as allergy to cats, primarily because:

• Dogs are usually kept outside.
• Dogs are kept outside of bedrooms.
• Dogs are washed regularly.

Once dog allergy is confirmed, the best way to decrease allergy symptoms is to remove the dog from the home. As with cat allergy, you can also use medications and allergy immunization.

Horse Allergy:

Patients often overlook and mistake allergy to horses, for allergy to pollens or molds. These patients are usually allergic to horse hair and dander. Treatment for this allergy would include medications, horse avoidance and/or allergy immunization to decrease the sensitivity to horse allergen.

Rodent Allergy:

Patients become allergic to rodents due to exposure to these animals in their daily work. The most common people at risk are veterinarians, laboratory technicians, and people who live in close quarters with rodents (such as pet owners and those who live in rodent-infested homes). Some examples of common rodents that humans come in contact with include mice, rats, and guinea pigs.

The rodent's urine has a high concentration of protein, which is the primary allergen to humans. The urine is often sprayed rather than deposited, thereby increasing human exposure. After the urine dries, the urinary proteins become airborne and are inhaled, leading to allergic symptoms.

Rabbit Allergy:

Patients become allergic to rabbits due to exposure to these animals in their daily work. The most common people at risk are veterinarians, laboratory technicians, and pet owners. The rabbit's saliva and fur are the common allergen.

Cockroach Allergy:

Roaches, especially the German Cockroach, are a very common pest in crowded cities worldwide. Recent studies have shown exposure to roach droppings as a major risk factor for the development of allergies and asthma in the inner city. Avoidance consists of roach baits and traps, extermination, and cleanliness. Avoid leaving food out in open containers, and try to routinely wash dishes after each meal and keep your cupboards free of food debris. Unfortunately, one can't encourage cleanliness in their neighbors! Patients who are not responsive can be treated with medications and allergy immunization.

Dust Mite Allergy:

Dust mites are approximately 0.3 millimeters in length, too small to be seen with the naked eye. They are eight-legged and sightless, and live on skin scales and other debris. Mites excrete partially digested food and digestive enzymes as a fecal particle, which release allergens very rapidly. Most patients allergic to dust mites are actually allergic to the dust mite feces. The mite fecal pellets are similar to pollen grains in three major ways:

• The fecal particles size
• The quantity of allergen carried
• The rate of proteins release

By being so similar to pollen grains, they are just the right size to cause allergies. Dust mites become a part of our environment and lifestyle because of their natural adaptations. Since they are entirely dependent on ambient humidity for hydration, and they are unable to search for environmental water supplies, they tend to live in places that “store” water. This may include carpets, sofas, mattresses and clothing. As humidity falls, mites withdraw from the surface and migrate to where there is more humidity e.g., deeper in the mattress. Even in very dry conditions, it may take months for mites to die and for their allergen levels to fall.

Avoiding and protecting yourself and your family from dust mite allergies can be summarized as one important rule-keep dust mites away from coming in contact with you! Washing your bedding at least once a week will reduce the number of dust mites you may come in contact with.

Conclusion

The medications used to treat animal allergy are similar to those used to treat other forms of allergy such as seasonal allergies and asthma. They include antihistamines, nasal steroids, and asthma pills and sprays. You should discuss which of these medications would best suit your symptoms with your allergy or asthma specialist. Allergy immunizations work basically by gradually building immunologic tolerance to the specific antigens you are allergic to. This process usually begins with weekly injections and gradually progresses to monthly injections that can be halted after three to five years of therapy with a good chance of maintaining your immunity to a particular antigen. Although roaches and dust mites may not be your idea of pets, getting rid of these creatures may significantly improve your tolerance of the pets you love.