Allergies FAQ

What are allergies, and how do they affect dogs? 
One of the most common conditions affecting dogs are allergies.  In the allergic state, the dog’s immune system “overreacts” to foreign substances (allergens or antigens) to which it is exposed.  These overreactions are manifested in three ways.  The most common is itching of the skin, either localized (one area) or generalized (all over the dog).  Another manifestation involves the respiratory system and may result in coughing, sneezing, and/or wheezing.  Sometimes, there may be an associated nasal or ocular (eye) discharge.  The third manifestation involves the digestive system, resulting in vomiting or diarrhea.

Aren’t there several types of allergies? 
There are five known types of allergies in the dog: contact, flea, food, bacterial, and inhalant.  Each of these has some common expressions in dogs, and each has some unique features.

What is inhalant allergy?
The most common type of allergy is the inhalant type, also known as atopy.  Dogs may be allergic to all of the same inhaled allergens that affect humans.  These include tree pollens (cedar, ash, oak, etc.), grass pollens (especially Bermuda), weed pollens (ragweed, etc.), molds, mildew, and the house dust mite.  Many of these allergies occur seasonally, such as ragweed, cedar, and grass pollens.  However, others are with us all the time, such as molds, mildew, and house dust mites.

What happens when a dog inhales something to which it is allergic? 
When humans inhale allergens, we express the allergy as respiratory problems.  These include coughing, sneezing, a runny nose, and watery eyes.  The dog’s reaction, however, usually produces severe, generalized itching.  It will chew, lick, or scratch almost any area of the body, including the feet.  Chewing and scratching produce hair loss and inflamed areas of the skin.  Saliva will stain light colored hair, so dogs that lick excessively will have orange or reddish brown hair.  This is often seen on the feet.  Although most people think that itching is related to fleas, the most common cause of itching in the dog is inhalant allergy.

What is causing my dog’s allergy? 
That is not a question that can be answered easily.  The itching produced by ragweed allergy is the same as that produced by oak pollen allergy.  In other words, an individual animal or person can be allergic to many different things with the end result (itching) being the same.  In some cases, allergy testing can make specific determinations, and sometimes an educated guess can be accurate if the itching corresponds with the blooming season of certain plants.  However, it is not always necessary to know the specific allergen for treatment to be successful.

What is meant by “seasonal allergy” and “year round allergy?” 
As the names imply, some dogs only have allergic reactions during specific periods of the year.  Others will itch year round.  A year round allergy occurs for two reasons.  First, the allergen is present year round.  This is the case for indoor dogs that are allergic to house dust mites, also known as “house dust.”  Second, the dog is allergic to so many things that at least one of those allergens is present at all times.

My dog seemed to have a seasonal allergy for several years, and now it seems year round.  Is that possible? 
Not only is that possible, it is almost expected.  As the dog ages, it usually becomes allergic to more and more things.  After several years of acquiring new allergies, it reaches the point that it is constantly exposed to something to which it is allergic.

My dog seems to have a grass allergy.  Does that mean it should not walk on grass?
No.  Dogs that are allergic to “grass”,  for example, are really allergic to grass pollen.  The blades of grass will cause no harm to your dog.  Bermuda grass is the most allergenic grass because it releases so much pollen into the air.  Keeping it mowed so it does not pollinate seems logical, but your neighbors must do the same because the pollen is airborne.  The same principle applies to trees.  Dogs are not allergic to the wood of a certain tree, only to its pollen.

My dog has fleas.  Couldn’t that be causing the itching?
A dog with inhalant allergy will itch even if fleas are not present.  However, if fleas are crawling around on your dog, the itching will increase.  Although getting rid of all of your dog’s fleas will not stop the itching, it will make it much easier to control the itching successfully.

My dog has a terrible odor.  Is that related?
There are two possible causes of odor associated with inhalant allergy.  These dogs are very prone to ear infections because the ear canal is an extension of the skin.  When it becomes inflamed, it is easily infected.  These dogs are also likely to have seborrhea.  Sebum is the oily material normally produced in the skin.  When a dog scratches, sebum production increases dramatically.  This produces a musty odor.  A bath will remove the odor, but it is gone for only a few hours.  The key to controlling seborrhea is to stop the itching and scratching.