Update on Dog, Cat, and Other Pet Allergies

In the U.S., dogs are the most common pets. According to the American Veterinary Medical Association, approximately 77 million pet dogs are living in the country spread around roughly 49 million homes. This means that each dog-owning household has an average of 1.5 dogs. The most common breed of dog is the Labrador Retriever. The second most common pets are cats. According to the American Veterinary Medical Association, there are about 32 million homes in the U.S. with cats comprising of approximately 59 million cats in total. Thus, the average cat-owning home has an average of 1.8 cats. The most common breed of cat is the Ragdoll. Fish, birds (e.g., parakeets, cockatiels, parrots), reptiles (e.g., lizards, turtles, snakes, geckos), rabbits, poultry (e.g., chickens, ducks, turkeys, geese), hamsters, guinea pigs, and ferrets round off the top 10 most common pets in the U.S. in that order. Overall, about 70% of homes have at least one pet. The number of pet-owning households continues to rise compared with ownership in the past.

It should also be noted that approximately 4 million households’ own horses. Horses do not normally live in people’s homes, but they still may be rather allergenic. In recent years, it has become fashionable to own miniature horses, which in some cases, do live in their owner’s home. Living with a horse in one’s house is probably not a good idea, but for those who are allergic to horses, it is especially ill-advised.

Whereas Wyoming is the top state for pet ownership at 71%, Idaho residents have the greatest number of dogs owners at approximately 59%. In contrast, Washington, DC has the least number of pet-owning households at 39%. Of note, 46% of Vermont residents have cats in their home making it the highest in the nation.

In general, a pet allergy is caused by an allergic reaction to specific proteins that are only found on the pet in question. The classic symptoms of pet allergies may include sneezing, runny nose, nasal congestion, post-nasal drip, sinus congestion, itchy nose, itchy throat, itchy eyes, watery eyes, red eyes, chest tightness, coughing, wheezing, and/or shortness of breath. The diagnosis of a pet allergy is done by taking a comprehensive history and physical examination of the patient in combination with allergy testing (i.e., blood tests, skin tests). Once the diagnosis is made, the best approach is prevention. If an individual can avoid being exposed to the pet, no other treatment is generally needed. If they must be exposed or refuse to avoid the animal, then the treatment may consist of oral antihistamines, oral, decongestants, leukotriene antagonists, nasal corticosteroids, nasal antihistamines, nasal anticholinergics, ocular antihistamines, ocular mast cell stabilizers, inhaled bronchodilators, inhaled mast cell stabilizers, and/or inhaled corticosteroids. For those who decide to live with their pet, allergy shots (allergy immunotherapy, allergy injections, allergy desensitization, allergy hyposensitization) may be indicated. Allergy injections are very effective as they work in 80-85% of individuals who take them. They have been given to patients for over 100 years and they are generally given for a period of 3-5 years.

People who are allergic to dogs usually have a reaction to the major protein called “Can f 1,” which is found on dogs. Specifically, the dander of dogs contains this major dog protein, Can f 1. It should be noted that the furry hair of a dog, which is not allergenic, may also transport other allergens (i.e., dust, pollens) to sensitive allergic individuals causing them to be exposed to more dust and pollens.  The dander of a dog can stick to an individual’s clothing, bedding, carpeting, etc., but with less affinity.  In addition to the dog’s dander, the Can f 1 protein is also found in a dog’s saliva and urine.  It is important to note that a dog allergy will cause perennial symptoms, unlike pollen allergies which generally affects individuals in certain seasons.

Individuals with cat allergies have a very similar situation to those with dog allergies, however, the major proteins responsible for the allergic reaction are named “Fel d 1” and “Fel d 4.” These proteins are found in the sebaceous glands of the skin (i.e., dander), the saliva, and the urine of cats. The dander of a cat tends to “stick” to things such as walls, bedding, carpeting, clothes, etc. Even with professional cleaning, it still takes a long time (i.e., up to several months) for the levels of cat protein to decrease to tolerable levels. Thus, removing a cat from one’s home for a few weeks is not long enough to determine if the cat is the problem. One misconception that is quite common is that there are “hypoallergenic cats.”  All cats have the capacity to induce allergic symptoms to cat-sensitive individuals. Some patients feel that they can tolerate short-haired cats better than long-haired cats, but studies do not support this theory. Brushing and bathing your cat regularly will however reduce the cat protein levels that cause allergic symptoms and of course is advisable.

Bird and rodent allergies are similar to other pet allergies except that in addition to the dander, the proteins responsible for the allergic reaction are also found in the urine, fecal, and feather particulates in birds and in the urine, saliva, and fecal droppings in rodents (e.g., hamsters, guinea pigs, mice, rats, gerbils, chinchillas). It is important to point out that in addition to allergies, both birds and rodents pose another threat to one’s health. Exposure to birds can cause more than 60 infections and diseases. Some of these may include avian flu, avian tuberculosis, psittacosis, salmonellosis, allergic alveolitis, campylobacteriosis, giardiasis, Newcastle disease, histoplasmosis, and cryptosporidiosis. Exposure to rodents (e.g., mice, rats) can cause many diseases as well such as the hantavirus pulmonary syndrome (HPS), tularemia, leptospirosis, salmonellosis, bubonic plague, rat-bite fever (RBF), Lassa fever, and lymphocytic choriomeningitis.

Allergies to reptiles are not common.  There have been reports of allergies to snakes, and of course there is always the possibility of an allergic reaction to the venom of certain snakes. There have also been reported cases of allergies to various reptiles, particularly iguanas. In addition to the typical allergy symptoms that occur with other pets, there seems to be more skin irritation with reptiles than with other pets.

Horse allergies are not that uncommon.  Individuals that are allergic to horses typically have similar symptoms as people with cat and/or dog allergies. The dander is the most common way in which horses cause allergic symptoms in humans.  The horse’s saliva, urine, and the fecal material dropped by horse mites are other ways that people are exposed to the allergenic proteins of horses. There is an increased incidence of horse allergy in some individuals that have cat and/or dog allergies due to a common protein that is shared between all 3 animals.

The board certified allergists at Black & Kletz Allergy have been diagnosing and treating pet allergies in both adults and children in the Washington, DC, Northern Virginia, and Maryland metropolitan area for more than 50 years. Black & Kletz Allergy has 3 offices in the Washington, DC metropolitan area with locations in Washington, DC, McLean, VA (Tysons Corner, VA), and Manassas, VA. All of our offices have on-site parking and the Washington, DC and McLean, VA offices are Metro accessible. We offer a free shuttle that runs between our McLean, VA office and the Spring Hill metro station on the silver line. If you suffer from a pet allergy or are not sure if you do, please call us to and make an appointment at one of our conveniently located offices. Alternatively, you may click Request an Appointment and we will respond within 24 hours by the next business day. The allergy specialists at Black & Kletz Allergy are confident that we will be able to help you with your furry friends.