Itchy scratchy

Meet Itchy and Scratchy. They are the two most common complaints my clients call me about. Now sometimes, this is just a simple case of an ear infection or bug bite or even a nervous animal that chews itself like people chew their nails. But most often Itchy and Scratchy are present because of allergies.

An allergy is an abnormal response of the immune system to a normal, non-harmful, part of the pet's environment. This may be a pollen, bug bite or component of their food. The most common type of allergy that we see in dogs is called atopy. Next most common is flea allergies. Not all flea bites will cause a dog to itch. But a flea allergic pet will have a strong, very uncomfortable reaction to even a single flea bite. And finally, food allergy which is an abnormal reaction to a protein in the animal's food.

Atopy is also identified as environmental or seasonal allergies. Atopy is triggered by substances that the animal comes in contact with through the skin or respiratory tract. In animals, the allergy shows itself with skin reactions. These are the dogs and cats with itchy feet, red itchy armpits and groin areas and chronic ear infections. They may show all of these symptoms or only one. They may become worse at certain times of year as certain pollens increase. They may be worse in one part of the country than another. Atopy typically develops when the animal is about 1 to 3 years old. It would be rare for atopy to show up after about 7 years of age.

Atopy is treated in a couple of different ways. The ideal treatment for atopy would be with hyposensitization, also called "allergy shots". In this treatment the animal is tested to determine the exact things that it is reacting too. These allergens are then made up in a vaccine type injection and the animal is given a series of injections to try and train the immune system to stop overreacting to the allergens. This is the only treatment that really treats the underlying cause of the allergy symptoms. Sometimes this treatment may not be possible or may not work for a particular pet. Other treatment options include suppression of the immune response with drugs. Cyclosporine is one option. This was originally designed as a post-transplant, anti-rejection drug. At lower doses it is safe and can be very effective at controlling the symptoms of atopy. Another treatment option is steroids like prednisone. While steroids are safe enough for short term treatment and can be life-saving in certain disease processes we have to be careful with long term use. Therefore, steroids are not an ideal way to treat atopy unless the symptoms are mild and the steroids can be used infrequently for short periods of time.

Flea allergies are the easiest allergies to treat. Prevention is key here. Keep your pets on regular, year-round flea control and you will never have to worry about them being allergic. If you get behind and your pet gets fleas, removing the fleas and treating the symptoms of the allergy will fix the problem. Flea allergies are usually identified by a very characteristic area of irritation, usually around the base of the tail, extending up the spine and sometimes around the base of the ears. The area will be come very red, possible swollen. Often hair will fall out and the pet may develop secondary bacterial infections leading to more irritation and hair loss. And, of course, if we find fleas on the exam we become even more suspicious of a flea allergy.

And finally, food allergy. Spend any time in a pet store and you are going to hear stories about food allergies and food allergic dogs. However, the actual incidence of food allergy is probably fairly low in the general pet population. And there are a lot of myths out there about food allergies. I hear two most commonly. The first is that their dog is on a "special" diet that doesn't cause allergies. But the truth is any diet can potentially result in an allergic reaction regardless of the components. All it takes is protein from the food, and all food contains protein, to interact with the immune system leading to an abnormal reaction by the immune system and resulting in an itchy dog. The second myth I hear a lot is that their dog has been eating the same food for years so it can't be allergic to it. But it takes multiple exposures, possibly over months to years to lead to an allergic response. So a dog that suddenly develops itchy skin at 7 or more years of age is more likely to have a food allergy than atopy.

And just to complicate matters all of the allergies look pretty much the same: Itchy and Scratchy rear their ugly heads. And sometimes more than one type of allergy is present. It is thought that up to 30% of dogs with atopy also have a food allergy. This is especially true in those itchy dogs that may also show some intestinal symptoms such as soft stools, weight loss or vomiting.

Later this week I want to talk about how to diagnose a food allergy through a diagnostic test called an elimination diet. This is where you get to be the scientist or doctor at home, running a well designed experiment (no risk involved, I promise) on your dogs diet.

And if you have any interest in more myths about food allergies in dogs check out this link.