Atopy, Atopic Dermatitis, (previously also called Allergic Inhalant Dermatitis) is a condition affecting 10% of dogs.
Atopy is very much like hayfever in people. Both species inhale pollen, dust, molds, house dust mites or other allergens, then have an allergic reaction.
The difference is what dermatologists call the “shock organ,” or reactive part of the body. In people, the shock organ is the respiratory tract, so people tend to have runny noses, coughing, sneezing and sinus infections.
Dogs, instead, react with the skin, and typically the front of the body is affected most. Classic evidence of Atopy is itchiness in the face, ears, feet, axillae (armpits) and down the front of the front legs.
There are known to be 64 allergens that dogs can inhale and have an allergic reaction to.
(When you have finished reading this overview of Atopic Dermatitis, click here to read an update on the condition.)
Dogs who have ear infections early in life are likely to become Atopic later. Average onset of signs is 3-5 years of age, although I have seen puppies as young as 12 weeks with Atopy and dogs as old as 14 years having their first episode.
Many dogs affected with Atopic Dermatitis can be observed rubbing their faces in the carpet or pawing at their snouts. Eyelids may be inflamed, moist and even hairless. Roll the dog over and you are likely to see the axillary region inflamed and hairless.
Patients with chronic atopy and itchy feet may have dermatitis between the toes, top and bottom. Deep bacterial infection from long-term moistness will add to the itchiness. These infections are often characterized by highly resistant organisms. The syndrome is known as pododermatitis. Broken down the Latin prefix “podo” means “foot,” “derma” means “skin” and “itis” means “inflammation.”
Infection in other areas of the body is another common sequella of Allergic Inhalant Dermatitis. Here it is called pyoderma. Pyoderma affects the pores and hair follicles of the skin and, like infection in pododermatitis, adds to the itchiness. Long-term antibiotic therapy is needed for pyoderma and it is not unusual to treat these patients for months at a time. Convenia is effective in many cases, and is especially helpful in those patients who are difficult to pill.
In most cases pyoderma also needs to be addressed topically with shampoo therapy. Frequent shampooing has the added advantage of removing allergens little dustmop dogs pick up in the course of their everyday activities.
Other aspects of treatment of atopic dermatitis in dogs include oral medications that can include antihistamines such as diphenhydramine (Benadryl) and Hydroxyzine. Diphenhydramine is of limited value in most dogs. Its most-pronounced effect in people, drowsiness, can be dramatic in dogs, while its ability to control itchiness in the species is very limited. Hydroxyzine is commonly used for atopy. It is safe, highly effective and reasonably-priced.
Oral and/or injectable corticosteroids can play a part in short- and long-term treatment of atopic dogs.
Another method of oral therapy is Atopica, by Novartis Animal Health. Atopica: is a cyclosporine product FDA-approved for use in this condition, and effective in many cases.
Another form of treatment is commonly referred to by laymen as “allergy shots,” although the correct term is hyposensitization. The Latin prefix “hypo” means low or below, so the process decreases sensitivity. In other words, the immune system, which is reacting inappropriately to pollen, dust and molds, is “told” to back off in its reaction.
The process involves giving injections of the very things the patient is allergic to. In doing so, the immune system is “taught” to react less and less to the offending allergens.
There are two ways to get to the point of hyposensitization injections.
Board-certified veterinary dermatologists can perform skin testing. The technique is similar to patch testing that is done on people. Instead of allergens being under patches, tiny amounts of allergens are injected into multiple places to allow the dermatologist to “read” the reactions to the injections and determine which allergens are offensive to an individual pet. That report is sent to a laboratory, which makes hyposensitization solution specific for the individual pet tested.
In vitro testing begins with a blood sample, which is sent to a laboratory that tests for evidence of reactions to various allergens. In vitro testing may be performed by any veterinarian. The evidence is in the form of antibodies, proteins the immune system has created that are specific for the body’s reaction to each different type of allergen. The same company that determines which allergens’ antibodies are present also makes the hyposensitization solution for the patient.
Either the dermatologist or the primary care veterinarian teaches the pet owner how to give the injections, which are continued for a lifetime. If, at some point, the patient ceases to be under control, testing may be repeated to see if new allergies have developed.
Atopy is a condition that must be constantly monitored, but can be controlled in virtually every patient. Unlike some allergies in children, however, it does not go away, and treatment will be required for a lifetime.
My dog had been given vetalog about 2yrs ago and she is broke out again so I was wondering would metronidazole work as the same as the vetalog.
Sorry, Chessie, but Vetalog is a corticosteroid and metronidazole is an antibiotic and antiparasitic with antiinflammatory properties, but nowhere in the category of pharmaceuticals that Vetalog is. Your pup is simply going to have to go see his veterinarian. Thank you for reading http://www.MyPetsDoctor.com.
I have a question concerning my baby Bella! She is one yr old and is solid white. She is having horrible allergy problems so much so that she turns pink on most of her body. She is on prednisone now but she has gained weight. Now she is getting too heavy for her little legs. Our veterinarian said white dogs are more prone to allergies than any other color. True? If so, I would like to know is there a better way to treat than with Prednisone? Bella is a Chihuahua and weighed 3 lbs 4 ozs at six months. Now she is 6 lbs. Clearly too much! Just need a second opinion. Hope you don’t mind me asking because I am very worried. I was also told this breed doesn’t live very long. Thanks, Sue
Skin problems can be difficult to treat and difficult for the pet owner, too, because, in the case of allergies, they never go away and often require a big time investment for the owner. That said, I don’t see much allergy problems in Chihuahuas.
Prednisone can be a good tool in allergy cases, but we try to minimize the dose to decrease side-effects. Ask your veterinarian whether he is willing to try other forms of treatment, such as hyposensitization. Click here to read several articles I’ve written about hyposensitization on our blog, http://www.mypetsdoctor.com/. If he is not, ask him whether he can refer you to a board-certified veterinary dermatologist. That way you can get a specialist to perform the necessary diagnostics to obtain treatment with fewer side effects.
You are correct to be concerned about Bella’s weight. Her tiny frame cannot handle that much weight. While prednisone will make her retain a little water, you can still control how much she eats. Ask your veterinarian for a goal weight and a feeding allowance, feed her on a meal schedule. Pick two or three times each day for her to eat at the same time every day, put the food down for 15 minutes, then take it up, whether she has eaten none or all. Do not exceed the total daily allowance of food. She can lose weight, even in the face of prednisone administration.
Do you live in Corpus Christi? I don’t know any veterinarians there, but I have a friend who is a board-certified dermatologist and I can ask him for a recommendation for your city, wherever that is, if he knows someone there.
Good luck, and please keep me posted on Bella.
My sister has an 8 year old spayed female golden retriever mix who exhibits most of the signs of Atopy that you mention, particularly rubbing her face on the ground, and has since she was about a year old. We’ve taken her to multiple veterinarians, who’ve prescribed everything from steroids to medicated shampoos and put her on special diets to test for food allergies (which she doesn’t seem to have, based on her lack of improvement on grain-free diets). Some of these treatments have produced short-term improvement but nothing has had any lasting benefit. The poor dog chews her paws and skin constantly if not wearing an Elizabethan collar, she smells terrible even if bathed just hours ago, and we’re at our wit’s end trying to help her. Our most recent veterinarian mentioned Atopica but advised trying some other (cheaper) treatments first, which we did with no real improvement. So now we’re considering asking him to prescribe Atopica. We’ve heard that a generic is an effective and more reasonably-priced alternative but some who’ve used it say that Atopica produces better results. Can you comment on Atopica vs. generic? Also, would you try the long-term antibiotic therapy you mention before prescribing Atopica, and if so, what type of oral antibiotic would you use? (The dog in question is very easy to pill, so oral meds are fine.) Thanks for your assistance and your very educational and interesting blog!
Interesting article! Are certain breeds of dog more likely to suffer from this? Also, are certain geographic locations more likely to have allergic dogs? (Urban vs rural, or plains vs mountains for example)
The geographical question, Amy, is an interesting one. In general, places where dust, pollen and molds occur in the highest concentrations are more likely to harbor allergy victims. For example, despite the wonderful things I said in today’s post (7-28-10) about my own Mississippi Gulf Coast home, it is known to be one of the allergy capitals of the world. Formerly the desert southwest, dry and barren, was considered a good place for allergy sufferers to go. But, “immigrants” brought their plants from home and, along with irrigation, created a place that could artificially produce pollen. Now allergy sufferers no longer go the Phoenix for relief.
Breeds that are overrepresented on the atopy charts include spaniels, especially the Cocker, Labrador retrievers and West Highland Terriers.
We hope your book sales are doing well, Dr. Randolph.