Your Pet's Health - Atopy -- In Cats & Dogs

Allergies & Atopy in Pets

There are many reasons for dogs and cats to be itchy and Atopy is typically the #1 reason. Atopy refers to the genetic tendency to develop allergic diseases such as allergic rhinitis, asthma and atopic dermatitis (eczema). Environmental allergies such as grass, trees, weeds, pollen & etc. can affect your pets health. Food Hypersensitivity is overdiagnosed but is a reason for pruritus.
--Parasites (fleas, mites, ticks, lice)
--Bacterial infection (most commonly staphylococcus bacteria; “staph” infection)
--Fungal infection (Malassezia yeast or dermatophytes; “ringworm” infection)
--Allergies to food or environmental allergens like dust mites or pollens
--Autoimmune diseases like pemphigus foliaceus
--Skin cancer called epitheliotropic lymphoma

Symptoms of Atopy in Dogs and Cats

Dogs
The main symptoms of atopy in dogs are itching and recurrent infections. Dogs relieve itch by licking, chewing, scooting, rubbing, or scratching. Dogs rarely perform these behaviors out of boredom or anxiety, although being bored or anxious makes things worse. Infections are typically yeast and/or bacterial infections of the skin and ears. The ears may be the only affected area in a younger pet, progressing to the full body usually before age 6 years. Another area typically affected is the feet. If you look between the toes you may notice the skin there is red or your dog chews the feet or licks the legs. Then the axillary regions, abdomen, chest, under the neck, and anal area are often affected- the skin may be red, greasy, smelly or itchy. With long term issues, the skin becomes darker and thicker. The hair may be missing or shorter due to infections and chewing. Some dogs lick huge sores on their lower legs. Some dogs have red, runny eyes and may sneeze due to allergies.

Cats
The main symptom of atopy in cats is itching. Cats will scratch, bite their skin, pull out hair, and overgroom to help relieve itch. Cats rarely perform these behaviors out of boredom or anxiety, although being bored or anxious makes things worse. Cats with atopy get skin and ear infections much less often than dogs do, but they certainly occur. Cats most often make bald patches on themselves, usually the lower abdomen is the worst area, and with progression, raw areas are created with the cat’s raspy tongue. Cats often will scratch at the head with the hind leg and create scabs around the eyes and ears. Cats can manifest allergies with asthma too, but it is fairly rare to have asthma and skin symptoms at the same time.

What Type of Atopy Could My Dog or Cat Have?
There are two basic types of atopy that cause skin itching and recurrent infections once parasites are ruled out- food allergy and environmental allergy. Pets can have both of these allergy types at the same time. Atopy in dogs typically start with symptoms between the ages of 1-6 years. Symptoms can wax and wane, but typically worsen up to the age of 6 and level off. As pets with atopy get older, they tend to get more frequent infections along with itchiness.

Food Allergies & Atopy
If your pet had allergy symptoms start at younger than 1 year of age, the symptoms are year round, or there are any gastrointestinal signs like vomiting, loose stools, or having more than 2 bowel movements per day, food allergies are more likely. Most pets with allergies don’t have food allergies, only about 5-10% of dogs and perhaps 30% of cats do. There is no diagnostic test for a food allergy other than an elimination diet trial. If a pet responds to a food trial, then we can go about the tedious task of determining exactly what they are allergic to, or we can simply find a diet they do well on and stick with it.

Environmental Allergies
Over 80% of all pet allergies are reactions from environmental allergies. Some may be seasonal with outdoor allergies, or year round with indoor allergies. Most pets have a combination of indoor and outdoor allergies. To determine what allergens in the environment are causing your pet to have symptoms, we can perform allergy testing.

Treatments for allergies in dogs and cats
If there is a food allergy, the offending foods must be avoided. To control environmental allergies, sometimes short courses of medications are needed. If allergic symptoms recur quickly when treatments are stopped, long term treatments are needed. Some pets need antibiotics and antifungals in addition to medications that control the inflammation in the skin. When the inflammation is controlled, the itch resolves.

Why Allergy Test?
Allergy skin testing determines what things in the environment are causing your pet to be itchy. From the results of the test, allergy injections can be formulated to desensitize to what the pet is allergic to. Avoidance of allergens would be ideal, but unfortunately most allergens in the environment are airborne and cannot be avoided. Examples of common allergens include pollens, dusts, and molds.

Some pets are not good candidates for allergy testing and allergy shots. We will discuss if this is a good option for your pet at your appointment.

Allergy -- General in Dogs
In the dog, the most common symptom associated with allergies is itching of the skin, either localized (in one area) or generalized (all over the body). In some cases, the symptoms involve the respiratory system, with coughing, sneezing, and/or wheezing. Sometimes, there may be runny discharge from eyes or nose. In other cases, the allergic symptoms affect the digestive system resulting in vomiting and diarrhea.

How Common are Allergies in Dogs?
Unfortunately, allergies are quite common in dogs of all breeds and backgrounds. Most allergies appear after the pet is six months of age with the majority of affected dogs over age one or two.