Canine allergies

They cause Fido's itchy skin, not runny nose


Dust mites.
Dog food.

Lassie or Lad might be scratching like crazy, digging open sores on tortured skin, sores that cause infections, foul odors, and misery – and the culprits could well be part of their natural environment.

In short, Lassie or Lad might be allergic to flea saliva, grass or tree pollen, mold spores, microscopic spider-cousins that live in dust bunnies, or an ingredient in commercial dog food.

Pollen and dust granules are inhaled by dogs just as they are by dog owners, but instead of producing sinus congestion and a sore throat, they cause the skin to itch, the hair to fall out, and, with prolonged scratching, the eruption of pustules that often become infected. A flea or two can add to the misery, and if Lad is allergic to something in his diet as well, watch out. Allergies can lead to stomach and intestinal problems, including vomiting and diarrhea, and are often accompanied by ear infections.

Some breeds of dogs seem to be prone to development of allergies, but all dogs can be affected.

Inhalant allergies

Allergens are substances in the environment that cause the immune system to react as if invaded by a foreign body. If all dogs reacted to these substances, they would not be allergens, they would be toxins.

These allergens cause mast cells in the skin and basophils (specialized white blood cells) in the blood to release antibodies that contain histamines, serotonin, and leukotrienes. These antibodies are responsible for allergy symptoms.

Some inhalant allergies are seasonal. Dogs may be affected by inhaling grass pollen in spring and summer or ragweed pollen in late summer and early autumn. If this is the case, the dog will start to scratch and bite his body, lick his paws, shake his head, and rub his face along the carpet for relief from the itch when pollen grains are swirling in the air.

However, many dogs suffering from allergies itch somewhat year-round because they are also affected by household dust, mold spores, and other irritants.

Treatment for inhalant allergies ranges from keeping Lassie comfortable with cool baths in shampoos or rinses containing aloe vera, oatmeal, or eucalyptus to drug therapy to interrupt the itch cycle until the skin can be healed and the allergen has (hopefully) diminished.

Inclusion of Omega 3 and Omega 6 fatty acids in the diet can also help keep skin supple and healthy. Many dog food companies add these fatty acids to their premium foods. Supplements such as Missing Link provide not only the Omega oils but also a balance of vitamins and minerals necessary for good skin and coat health.

Environmental controls include frequent vacuuming and dusting of the areas where the dog spends time and keeping his bedding dust-free.

Some dogs may get relief from antihistamines such as diphenhydramine (Benadryl), clemastine (Tavist) or chlorapheniramine (Chlortrimetron), but owners should ask their veterinarian for proper dosage for their pet and may have to try more than one before finding the formula that helps.

Steroids such as prednisone interfere with the immune system function so that the body no longer considers the allergens to be invaders. Steroids should be used carefully and sparingly as they may cause liver problems and, in older dogs, can trigger a form of Cushing’s disease. Steroids also increase appetite and thirst, cause more frequent urination, and can increase aggression in some dogs. However, small doses of predisone can be invaluable in treating a dog with chronic or acute allergic reactions when all else fails.

Dogs with allergies can scratch and bite themselves into skin infections that need treatment with antibiotics. Prednisone is often prescribed for these dogs to get the itching under control while the antibiotic deals with the bacterial infection.


Some dogs become allergic to flea saliva. If this is the case, the bite of a single flea can send a dog into a paroxysm of chewing, especially around his tail and on his belly and inside hind legs. Dogs with flea bite allergy are often frantic to ease the itching and may chew themselves raw.

Top on the list for avoiding flea bite dermatitis is to control fleas. First line of defense is regular grooming of the dog, right down to the skin, to find fleas or flea droppings. Flea products are much safer for dogs and dog owners these days. Veterinarians have an arsenal of flea products to choose from, including once-a-month treatments and pills and shampoos, sprays, and premise foggers with growth regulators and genetically-engineered pyrethrin (daisy) ingredients. Many over-the-counter flea products also contain growth regulators and pyrethrins.

Some dog owners swear by garlic and brewer’s yeast to keep fleas away, but no evidence exists to prove these plant products are valuable preventives. Other dog owners plant herbs such as pennyroyal, southernwood, or wormwood around dog kennels or near doorways and use herbal flea collars, brush lavendar or eucalyptus oil into the dog’s coat once a week, or sprinkle dried leaves of lavendar, rosemary, sage, or eucalyptus in the dog’s bed to keep the little bloodsuckers at bay, but the jury is still out on effectiveness.

While waging all-out war on fleas, dog owners should also use the same treatments that work for inhalant allergies to reduce the itching and ease the discomfort of irritated skin.

[More on fleas]

Food allergies

Some dogs that have allergies to other components of their environment will also exhibit some dietary problems, but whether these problems are true food allergies is often difficult to ascertain.

If food allergy is suspected, veterinarian can prescribe diets with protein and carbohydrate sources and other nutrients that the dog has not been exposed to. Lamb and rice used to be the combination of choice, but most premium dog food companies now have a lamb and rice diet, so hypoallergenic diets of fish and potatoes or venison and rice have taken their place.

Dr. Lowell Ackerman, a veterinary dermatologist, recommends home-cooked diets when food allergies or intolerances are suspected.

“Any suitable protein source may be mixed with rice and/or potatoes to create a hypoallergenic meal,” Ackerman wrote in Skin and Haircoat Problems in Dogs. “The meal is prepared by mixing one part lamb, rabbit, or venison (or other protein source to which the dog has never been exposed) with two parts rice and/or potatoes. All ingredients should be served boiled and fed in the same total volume as the pet’s normal diet. Once cooked, the meal can be packaged in individual portions, frozen, and then thawed as needed. This diet is not to be fed long-term. It is not nutritionally balanced to be a regular diet. It is only fed for one or two months at a time as a test diet.”1

When trying to isolate a food allergen, the dog must not get anything but the prescribed diet. If the dog tolerates the food well and the symptoms decline or disappear, other foods can be gradually reintroduced to determine which ingredient is the culprit. If the symptoms are not alleviated in four weeks, another hypoallergenic diet can be tried, and if it is not successful, further diagnostic tests are indicated.

1. Guide to Skin and Haircoat Problems in Dogs Lowell Ackerman /Paperback/1994, page 16

Additional resources for this article: UC Davis Book of Dogs : The Complete Medical Reference Guide for Dogs and Puppies, School of Veterinary Medicine Staff, Mordecai Siegal/Hardcover/1995, and Your Natural Dog by Angela Patmore (out of print)

If your dog makes you sneeze …

Just as Stoney may be allergic to grass pollen or dust mites, so Stoney’s owner may be allergic to something about his pet. Allergies often develop slowly as the body becomes sensitive to various things in the environment; just as the final straw is rumored to have broken the camel’s back, so the final allergen may trigger attacks and make life miserable. Fortunately, there are things to do to minimize the impact so that Stoney can remain with the family.

“If you are allergic to six things, get rid of three of them, and you may drop below your allergic threshold and become symptom-free,” said Dr. Karen Campbell, a small animal veterinarian at the University of Illinois College of Veterinary Medicine.*

Allergies to pets are caused by dander, hair or skin proteins, saliva, or fur itself. These hints can help minimize contact with these allergens and alleviate the discomfort they cause so that the pet can stay in the home or the family can acquire a puppy:

  1. If looking for a puppy, choose a breed that doesn’t drop dead hair. Hard-coated terriers, Poodles, and Bichon Frisé are considered to be hypoallergenic, that is, less likely to cause allergic reactions in susceptible people. (They are also less likely to drool, lessening the chance that saliva will cause allergic reactions in family members.)
  2. Keep Dusty’s skin healthy so that dander and skin eruptions don’t become problems. Bathe her every few weeks with a mild herbal or medicated shampoo, use a canine cream rinse on her coat, and feed her a diet or supplements that contain Omega 3 and Omega 6 fatty acids.
  3. Ask a non-allergic family member or friend to brush Fifi often.
  4. Discourage Toodles from licking or mouthing family members, sleeping on the bed, or climbing on the furniture.
  5. Do not allow Stoney to sleep in the bedroom.
  6. Wash dog bedding frequently to avoid build-up of dander, drool, dust, or hair.
  7. Eliminate as many other allergens from the home environment as possible by vacuuming and dusting often, using an electrostatic air purifier, changing furnace filters regularly, and moderating or ending use of perfumed cleaners or deodorizers that cause allergic reactions.

* As quoted in “Coping with allergic reactions to pets,” a pet column published by the University of Illinois College of Veterinary Medicine, September 12, 1994.

Norma Bennett Woolf

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