If I had to pin down the most commonly seen problems in our practice, I’d choose itching/ear infections for the “Top 5” list. We could spend an eternity talking about these problems, but I’d like to try to offer a brief introduction to the deeper reasons for these things to happen. We’ll have to start by defining the things that we can see on a physical exam (the stuff you notice at home); and then the underlying reason they’re happening.
Symptoms: shaking of the head, scratching ears, foul smell, goopy waxy discharge (brown or yellow or pus) in the ears, swelling/redness of the ear, major swelling of the ear flap.
What’s happening: ear infection, called otitis externa. It’s generally caused by inflammation of the skin in the ear canal, which makes the skin susceptible to an infection by bacteria and yeast.
Symptoms : licking and/or chewing at the feet, red-brown staining of the fur on the feet, redness/swelling of the skin between the toes, swelling of the feet.
What’s happening: skin infection, called dermatitis, usually caused by bacteria and yeast infections. The skin is itchy, which is why dogs chew/lick.
Symptoms: hair loss, itching, flaky skin, red skin, rashes on the belly/armpits/groin, bad smell, oily/dull/dry coat, peeling skin, crusty skin, or wet/sticky ulcers on the skin surface.
What’s happening: skin infection, usually by bacteria and sometimes yeast, because of inflamed skin surface.
In summary, dogs will have nasty ears, nasty skin, and ITCHING. It’s usually these things that drive an owner to call and make an appointment. It may be bad enough for an owner to lose sleep thanks to the licking or scratching going on all night long. (Dogs and cats both may also have gastrointestinal signs like vomiting and diarrhea from certain type of allergies.)
I’ll come right to the point. These signs and symptoms are NOT the underlying disease! We can treat the ears, feet, and skin with all sorts of different things. Ultimately, though, we’re just applying a bandaid that never really addresses the reason the dog is suffering these problems. We can provide temporary relief, up to a point.
The most common underlying cause of these chronic problems is an allergy. It’s not very common for dogs to have an anaphylactic response to something they’re allergic to. People who are allergic to shellfish, for example, will have swelling of the throat and go into shock if they eat shellfish. Thankfully, dogs don’t usually have such a violent response to an allergen. Pets can be allergic to things in the environment, or ingredients in their food.
With environmental allergies, we should think of the things that cause “hay fever” in people: pollen from trees/grass/weeds, dust, dust mites, molds. Dogs don’t get itchy/red eyes and runny noses as often as people do. They have all of those inflammatory reactions in their skin surface, which includes the ears and feet.
The other type of allergy that can cause trouble is a reaction to an ingredient in a dog’s food. The brand doesn’t matter, but the ingredients do! Corn, wheat, beef, poultry, and pork are very common ingredients in various types of dog food. Even a dog that has been eating the same food for several years can develop an allergy to the ingredients in the food. The brand doesn’t matter — the contents do.
Treating the allergy itself requires some testing to know exactly which allergy we’re dealing with. Some unlucky pets have both types of allergy (food and environmental). Thankfully, if we identify at least one of the allergy types, we can usually manage these pets successfully.
Testing for food allergy requires a special diet trial that lasts 8-12 weeks. Testing for environmental allergies requires either blood test or a skin test. THe skin test is much like the skin test that people get. Small injections are given in the skin, and the size of the red swollen area is measured to judge the response to the particular allergen that has been injected.
Treatment of an allergy consists of two major parts. First, we have to deal with the secondary effects of the allergy. This means treating the ear and/or skin infection aggressively. We may also need to control itching. Secondly, we need to treat the allergy itself. If we know what a pet is allergic to, we can treat that allergy directly. That’s the keystone!
Next week, I’ll start breaking down each type of allergy for a more in-depth look. In the meantime, how many of you have pets with chronic skin or ear problems?