Allergies are among the most common — and most frustrating — conditions in canine medicine. Unlike humans, who typically experience allergies as sneezing and watery eyes, dogs manifest allergic reactions primarily through their skin. The result is a dog that scratches, chews, licks, and rubs relentlessly, often causing secondary skin infections that compound the original problem.
Allergies in dogs are rarely cured outright — but with accurate diagnosis and appropriate management, most allergic dogs can live comfortable, good-quality lives. If your dog has been scratching persistently or developing recurrent skin or ear infections, contact Walker Lake Veterinary Centre at (587) 786-6771 for an assessment.
Allergies are the most common underlying cause of recurrent ear infections, recurrent skin infections, and chronic paw licking in dogs. If your dog has any of these problems repeatedly, an allergy investigation is warranted.
How Allergies Work in Dogs
An allergy is an abnormal immune response to a substance that is otherwise harmless. In an allergic dog, the immune system incorrectly identifies a benign substance — a specific protein in food, pollen from a tree, or a microscopic dust mite — as a threat and mounts an inflammatory response against it.
This inflammatory response manifests primarily in the skin in dogs, causing itching, redness, and breakdown of the skin barrier. Once the skin barrier is disrupted, bacteria and yeast that normally live harmlessly on the skin surface take advantage of the compromised environment, causing secondary infections that add further discomfort.
The result is a cycle — allergy causes inflammation, inflammation disrupts the skin barrier, disrupted skin allows secondary infections, infections cause more inflammation and discomfort.
Types of Allergies in Dogs
Environmental Allergies — Atopic Dermatitis
The most common type of allergy in dogs. Environmental allergies — also called atopic dermatitis or atopy — are caused by an immune reaction to airborne or contact environmental substances including:
- Pollens — tree, grass, and weed pollens
- House dust mites — among the most common allergens in dogs, present year-round in most homes
- Mould spores
- Dander from other animals
- Storage mites — found in dry dog food stored in bags
Environmental allergies typically develop between one and three years of age and are lifelong. Certain breeds have a strong genetic predisposition — West Highland White Terriers, Bulldogs, French Bulldogs, Labrador Retrievers, Golden Retrievers, Boxers, and German Shepherds are among the most commonly affected.
Food Allergies
A true food allergy is an immune response to a specific protein in the diet. The most commonly implicated proteins in canine food allergies are:
- Beef
- Chicken
- Dairy products
- Wheat
- Egg
- Lamb
- Soy
It is important to note that a dog can develop a food allergy to a protein they have eaten for years — food allergies develop through repeated exposure, not from eating a new food for the first time.
Food allergies and environmental allergies can be difficult to distinguish on symptoms alone, as both produce very similar signs. An elimination diet trial is the only reliable way to diagnose a food allergy.
Grain-free diets are not hypoallergenic. True grain allergies are relatively uncommon in dogs — most food allergies are reactions to animal proteins, not grains. A grain-free diet does not address the most common food allergens.
Contact Allergies
Less common than environmental or food allergies. Contact allergies develop when the skin reacts to direct physical contact with a substance — certain cleaning products, fabrics, plastics, rubber, or plants. Signs are localised to the areas of skin that come into contact with the offending material.
Flea Allergy Dermatitis
An allergic reaction to flea saliva — one of the most common and easily preventable allergies in dogs. A single flea bite can trigger intense itching in a flea-allergic dog. The reaction is not to the flea itself but specifically to proteins in the flea’s saliva injected at the time of the bite.
Flea allergy dermatitis causes intense itching concentrated at the base of the tail, lower back, and inner thighs. Year-round flea prevention is essential for flea-allergic dogs.
Signs and Symptoms of Allergies in Dogs
The hallmark sign of allergies in dogs is pruritus — persistent, often intense itching. How this itching manifests depends on the individual dog and the type of allergy.
Skin Signs
- Persistent scratching — particularly of the face, ears, armpits, groin, and belly
- Licking and chewing at the paws — often leaving reddish-brown saliva staining between the toes
- Rubbing the face along the carpet or furniture
- Red, inflamed skin — particularly in the armpits, groin, and between the toes
- Recurrent hot spots — areas of acute moist dermatitis
- Thickened, darkened, or leathery skin in chronic cases — lichenification
- Hair loss in affected areas
- Recurrent skin infections — bacterial pyoderma or yeast (Malassezia) dermatitis
Ear Signs
- Recurrent ear infections — one of the most consistent features of environmental allergy
- Head shaking and ear scratching
- Brown or dark discharge and odour from the ears
Gastrointestinal Signs
Food allergies in particular can produce gastrointestinal symptoms alongside or instead of skin signs:
- Chronic or recurrent diarrhoea
- Vomiting
- Increased frequency of bowel movements
- Gurgly, noisy intestines
Seasonal vs Year-Round Symptoms
Environmental allergies caused by pollens tend to be seasonal — worse during spring and autumn when pollen counts are high. House dust mite allergies cause year-round symptoms. Food allergies cause consistent year-round symptoms with no seasonal variation.
The pattern of symptom timing is a useful clue when distinguishing between allergy types.
Diagnosing Allergies in Dogs
Ruling Out Other Causes First
Before investigating allergies, a veterinarian will rule out other common causes of itching — parasites (particularly fleas, mange mites, and lice), skin infections, and ringworm. It is important to address these first as they can mimic allergy signs.
Flea Control Trial
Regardless of whether fleas are visible, a strict flea control trial — treating all pets in the household and the environment with a veterinary-recommended product for a minimum of 8 to 12 weeks — is an essential first step in investigating any itchy dog.
Elimination Diet Trial
If a food allergy is suspected, a strict elimination diet trial using either a hydrolysed protein diet or a novel protein diet is conducted for a minimum of 8 to 12 weeks. During this period, the dog must eat absolutely nothing other than the trial diet — no treats, flavoured medications, or table scraps.
If symptoms improve significantly during the trial and return when the original diet is reintroduced, a food allergy is confirmed.
Intradermal Allergy Testing and Serum Allergy Testing
For confirmed environmental allergies, allergy testing identifies the specific allergens causing the reaction. This information is used to formulate allergen-specific immunotherapy — the closest thing to a long-term solution for environmental allergies.
Over-the-counter allergy tests and breed-based food sensitivity panels are not validated diagnostic tools for canine allergies. Accurate diagnosis requires a systematic approach under veterinary guidance.
Managing Allergies in Dogs
Allergen Avoidance
Where possible, reducing exposure to identified allergens helps reduce the allergic load. This may include:
- Wiping down a dog’s coat and paws after outdoor walks to remove pollen
- Washing bedding frequently in hot water to reduce dust mite exposure
- Using air purifiers in rooms where the dog spends most time
- Avoiding known food allergens rigorously once identified
Allergen-Specific Immunotherapy
The most targeted long-term treatment for environmental allergies. A tailored course of injections or sublingual drops containing tiny amounts of the identified allergens gradually desensitises the immune system over months to years. Immunotherapy does not cure allergies but can significantly reduce their severity and the medications needed to manage them.
Success rates vary — approximately 60 to 80% of dogs show meaningful improvement with immunotherapy.
Medications for Symptom Control
Several effective medications are available to control allergic itch in dogs:
- Apoquel (oclacitinib) — a targeted oral medication that blocks specific itch signals. Fast-acting and effective for ongoing management
- Cytopoint (lokivetmab) — a monthly injectable biological therapy that neutralises a specific itch-signalling protein. Particularly useful for dogs that cannot tolerate oral medications
- Cyclosporine — an immunosuppressant used for moderate to severe atopic dermatitis
- Corticosteroids — effective for short-term relief of severe flares but not appropriate for long-term use due to side effects
Skin Barrier Support
Maintaining a healthy skin barrier reduces the impact of allergen exposure and reduces susceptibility to secondary infections. Veterinary-recommended shampoos, conditioners, and essential fatty acid supplementation all contribute to skin barrier health.
Managing Secondary Infections
Secondary bacterial and yeast skin infections require treatment with appropriate antibiotics or antifungal medications. Addressing secondary infections is often necessary before the response to allergy management can be accurately assessed.
If your dog has been scratching, developing recurrent infections, or chewing their paws, book an appointment at Walker Lake Veterinary Centre. Call (587) 786-6771 or book online. Located at 5109 22 Avenue SW, Southwest Edmonton.
Book an Appointment at Walker Lake Veterinary Centre
Walker Lake Veterinary Centre provides allergy assessment, skin cytology, elimination diet guidance, and ongoing allergy management for dogs and cats across Walker Lake, Summerside, Ellerslie, Heritage Valley, and Southwest Edmonton.
Call us at (587) 786-6771 or book online. We are located at 5109 22 Avenue SW, Edmonton.
Clinic hours:
- Monday, Tuesday & Thursday: 9:00 AM – 7:00 PM
- Wednesday & Friday: 9:00 AM – 6:00 PM
- Saturday: 9:00 AM – 3:00 PM
- Sunday: Closed
Frequently Asked Questions
Can dog allergies be cured?
Environmental allergies cannot be cured but can be effectively managed to the point where most dogs live comfortably. Food allergies can be resolved by permanently eliminating the offending protein from the diet. Flea allergy dermatitis resolves with consistent year-round flea prevention.
What is the difference between a food allergy and food intolerance in dogs?
A food allergy involves an immune response to a specific protein and produces skin signs alongside or instead of gastrointestinal signs. A food intolerance is a non-immune digestive reaction — typically producing gastrointestinal signs only. Both can cause diarrhoea and vomiting, but only a true food allergy causes skin and ear signs.
How long does an elimination diet trial take?
A minimum of 8 weeks is required to see a meaningful response, with 12 weeks preferred. Many dogs improve significantly within 4 to 6 weeks, but the full trial period is necessary to confirm the diagnosis and allow complete resolution of secondary infections that may be masking improvement.
My dog scratches mostly in spring and summer — is this allergies?
Seasonal scratching that coincides with high pollen counts is a classic presentation of environmental allergy to tree, grass, or weed pollens. This is one of the most common allergy patterns in Edmonton dogs due to the distinct seasons. A veterinary assessment can confirm the diagnosis and discuss management options.
Are some dog breeds more prone to allergies than others?
Yes. Breeds with known genetic predisposition to atopic dermatitis include West Highland White Terriers, Bulldogs, French Bulldogs, Boxers, Labrador Retrievers, Golden Retrievers, German Shepherds, Pugs, and Shih Tzus. However, any breed can develop allergies.
