Canine Allergy

Canine allergy is very common with over 1 in 7 having some type of allergy. The most common type of allergy is an inhaled allergen. Allergic reactions in dogs are different than what happens in people. In humans, allergies usually cause problems with breathing. In dogs, allergies usually affect the skin and cause itching.

Picture Dog Allergy on Face - Lhasa apso

Causes of Canine Allergy

There are 3 causes of canine allergy:

• Insects: Fleas (most common allergy, called flea allergy dermatitis) and other biting insects or parasites
• Airborne Allergens: Pollen, Mites, Grass, Mold that are inhaled (canine atopy).  These allergens can also be absorbed through the skin.
• Contact Allergies: Allergens that come in contact with the skin (contact hypersensitivity).
• Food and Drugs: called food allergies

Symptoms of Canine Allergy

Allergic reactions in dogs can either happen immediately after exposure to an allergen (something that causes allergy) or can be from a delayed reaction to an allergen.

Constant licking of paws and belly, rubbing the face and stuffy nose are common symptoms associated with allergy in dogs.  Ear infections are also common.

Canine Allergy by Type

Another common symptom of canine allergy is dog skin Itch, which can have several causes. Be sure to note when the itch started to aid your veterinarian with a diagnosis.  Canine skin itch can be caused by:

• Dog Inhaled Allergies (dog atopy): itch usually starts with the beginning of a new season, particularly in the late summer and fall during pollen season. Symptoms that indicate this type of allergy include belly, and paw licking, face rubbing, dog ear infection and dog ear scratching.
  
  Treatment for dog inhaled allergies involves the use of fatty acid supplements such as Dermaquin and a dog shampoo that contains colloidal oatmeal such as Lambert Kayes Oatmeal & Baking Soda Shampoo .  A veterinarian may also recommend antihistamine or corticosteroid sprays.  Allergy shots are also used.
  
  

  
  Picture of Dog Paw Allergy on Bull Terrier (Atopic Dermatitis)
  

• Dog Food Allergy: Symptoms of food allergy in dogs include paw licking, ear infection, recent changes in diet. A dog can develop a food allergy all of a sudden to a food that they have always eaten.
  
  Treatment for food allergy in dogs involves the use of an elimination diet, where a diet is pared back to a one simple protein and carbohydrate.  Once allergy symptoms have subsided, new components of food are added until the allergy returns.  At this point the last food added would be the cause.  This takes from 6 to 12 weeks (called a novel dog diet). As an alternative, some dogs, but not all, benefit from a hypoallergenic diet which uses smaller food molecules to avoid an allergic reaction such as Hill's Prescription Diet z/d or Purina Hypoallergenic HA.
  
  

  
  Picture Dog Food Allergy
  
  
  Canine Food Allergy  Dog Rear

• Contact Hypersensitivity (dog skin rash caused by something that touched the skin): This type of dog allergy usually occurs suddenly. Itching on the abdomen, feet and head is common.  If itch is occurring all over the body, then a substance you used on your dog such as a shampoo could be the problem.
  
  Using a dog oatmeal shampoo and a natural dog anti-itch spray such as Fidoderm can help to reduce dog skin itch symptoms. Your veterinarian can also prescribe a corticostedroid spray, oral medication or injection.
• Dog Skin Parasites: Dog flea allergy and mites (scabies) are the common causes of this type of this type of canine allergy.  Flea allergies tend to occur in dogs that haven't been exposed to fleas that often, while dogs that are constantly exposed develop a resistance. 
  
  Flea allergy dermatitis is the most common allergy in dogs. It is a reaction to flea saliva.
  
  Treatment involves the use of a dip such as Dermisil for Mange or Dermisil for Fleas. See our guide to canine fleas. Prevention of flea allergy is achieved with the monthly application of a product like Frontline Plus.
  

Canine Hives

Dog hives are Immediate allergic reactions (within 30 minutes) usually cause canine hives on the skin. They can appear anywhere and usually disappear in 24 hours. You can recognize hives by a raised appearance, circular shape and itch. Your dog’s hair may also be raised in patches.

Hives are most often caused by insect bites, drug allergy (after vaccination common cause), insecticides (lawn treatments), new foods or soaps.

Treatment of Hives

Hives disappear once the cause is no longer in contact with your dog. Determine what has changed in the past several hours such as a new food or if you took your dog on a walk to a new area.

For food allergies you can give your dog Milk of Magnesia (consult your Veterinarian first, suggested dose 7 to 25 ml. per pound orally once only) that quickens removal of food from your dog's stomach. If hives are caused by soap or insecticide, give your dog a bath using products you know are safe.

Like humans, you can also give your dog Benadryl(2 mg per pound orally every eight hours). For extreme cases your Veterinarian may also prescribe Cortisone treatments. The saliva in the fleas’ mouth causes flea allergies. A typical flea allergic reaction will have your dog itching the moment they come in contact with the fleas with the itch continuing even after the fleas are killed.

References:

Beale, Karin M. DVM, Gulf Coast Veterinary Specialists – “Atopic Dermatitis: Clinical Signs and Diagnosis”

Giffin, James M. MD & Carlson, Liisa D., DVM “Dog Owner’s Home Veterinary Handbook”.

Lloyd, Professor David, Royal Veterinary College, Hawkshead Campus: “Diagnosis & Management of Adverse Food Reactions in Dogs”

Osborn, Sarah Colombini DVM, Southwest Veterinary College, Houston: “Optimal use of Hypoallergenic Diets”

Ihrke, VMD, Professor of Dermatology, School of Veterinary Meicine, University of California: “Flea Allergy Dermatitis”

Washington State University College of Veterinary Medicine