Understanding Allergies

Atopic dermatitis (AD) is a chronic allergic skin condition that develops when a pet’s immune system overreacts to normally harmless substances such as pollens, dust mites, moulds, or grasses. These allergens trigger inflammation and intense itchiness, often leading to red, irritated skin, recurrent ear infections, and secondary bacterial or yeast infections.

Allergic skin disease is one of the most common causes of itchiness in dogs and cats, and while it cannot be cured, it can be well managed with the right long-term plan. Our team at McLaren Vale Veterinary Surgery understands how distressing it can be to see your pet constantly uncomfortable, and we’re here to help guide you every step of the way.

How Common Are Allergies?

• Around 10–15% of dogs are affected by atopic dermatitis.
• Environmental allergies are by far the most common cause.
• Food allergies account for only 5–10% of allergic skin problems.
• Flea allergy dermatitis (FAD) accounts for 40–50% of allergic skin disease in dogs.
• Many pets have more than one type of allergy at the same time.

Types and Causes of Allergies

Allergic skin disease can result from one or more of the following causes:

1. Environmental Allergies (Atopic Dermatitis)

This is the most common form and includes allergies to pollens, grasses, dust mites, and mould spores. These allergens are often impossible to avoid completely, as they are found in both indoor and outdoor environments. In most cases, treatment focuses on managing the symptoms rather than eliminating the allergens.

2. Flea Allergy Dermatitis (FAD)

Some pets are extremely sensitive to flea saliva, meaning that even a single flea bite can cause intense itching and inflammation.
Effective, year-round flea control is essential for every pet in the household.

3. Food Allergies

A smaller percentage of pets are allergic to ingredients in their diet, most often proteins such as beef, chicken, or dairy, but occasionally grains or additives. Because food allergies look identical to environmental allergies, we may recommend a strict food elimination trial to rule this out.

4. Contact Allergies

These occur when a pet’s skin reacts to shampoos, cleaning agents, plants, or fabrics. Contact allergies are less common but can contribute to irritation.

Why Allergic Pets Develop Secondary Infections

When the skin becomes inflamed due to allergies, it becomes hot, red, and humid. This creates the perfect environment for bacteria and yeast that naturally live on the skin to overgrow, leading to secondary infections.

These infections—known as pyoderma (bacterial skin infection) or Malassezia (yeast) dermatitis—can cause additional itching, redness, scabs, or an unpleasant odour.
Similarly, recurrent ear infections (otitis externa) are very common in allergic pets, especially when allergies are not well controlled.

Treating these infections is essential to restoring comfort and controlling the allergic cycle. Once the infection resolves, the underlying allergy must be managed to prevent recurrence.

Diagnosis: Finding the Cause

Because allergies can mimic other skin diseases, diagnosis requires a step-by-step process to rule out other conditions before confirming atopic dermatitis.

1. Rule Out Parasites and Infection

Skin scrapings to check for mites (such as Sarcoptes or Demodex).

Tape preps or cytology to identify bacteria or yeast infections.

2. Rule Out Flea Allergy

Implement strict flea control for all pets in the household, even if fleas are not seen.

3. Food Elimination Trial

We may recommend a strict 6-8 week elimination diet using a novel protein (a protein your pet hasn’t eaten before) or a hydrolysed diet (where proteins are broken down so the immune system doesn’t recognise them). During this period:

• No treats, table scraps, or flavoured medications are allowed.
• If the itching improves, the food may be the cause.
• If not, the allergy is likely environmental.

Our team can provide a detailed food elimination plan tailored to your pet’s needs. Please speak to your veterinarian for more information.

4. Allergy Testing

Once other causes have been ruled out, allergy testing may help identify specific environmental triggers. This is performed by dermatology specialists in Adelaide using:

• Intradermal skin testing (IDT) - a small number of allergens are injected under the skin to identify reactions.
• Serum allergy testing - a blood test measuring antibodies (IgE) to common allergens.

If allergy testing is suitable for your pet, our team can organise a referral to a dermatology specialist for further evaluation and treatment options.

Treatment and Long-Term Management

Allergies are managed, not cured, and treatment focuses on reducing itch, inflammation, and secondary infections. Each pet’s plan is tailored to their specific triggers and comfort level.

1. Medications to Control Itching and Inflammation

• Apoquel® (oclacitinib): An oral medication that blocks itch-signalling pathways. Works quickly and is suitable for long-term use.
• Cytopoint®: An injection that targets the IL-31 protein, responsible for triggering itch. Effects last 4–8 weeks.
• Corticosteroids: Useful for short-term relief during flare-ups but not ideal long-term due to side effects.

2. Restoring Skin Barrier Health

• Medicated shampoos such as Aloveen®, Pyohex®, or Malaseb® are often recommended depending on your pet’s condition:
  • Aloveen® helps soothe dry or irritated skin.
  • Pyohex® and Malaseb® contain antibacterial and antifungal ingredients to manage infections.
• Topical creams or sprays may contain steroids, antibiotics, or local anaesthetics to soothe irritation and treat infection.
• Omega-3 and Omega-6 supplements can help repair and strengthen the skin’s natural barrier, reducing inflammation.
• Regular bathing helps remove allergens from the skin and coat

3. Treating Secondary Infections

Bacterial and yeast overgrowths are very common in allergic pets. Treatment may involve:

• Medicated shampoos (antibacterial/antifungal)
• Topical treatments or wipes
• Oral antibiotics or antifungal medications, depending on severity

4. Allergen-Specific Immunotherapy (ASIT)

If specific allergens are identified through testing, custom immunotherapy can be developed. This involves medications to desensitise the immune system over time, reducing allergic flare-ups.

• Around 60-75% of dogs show improvement.
• Benefits may take 6-12 months to appear.

This therapy is available through referral dermatologists and is often the best long-term solution for environmental allergies.

Preventing Exposure

Where possible, it’s helpful to reduce contact with known allergens. For example:

• Use HEPA filters indoors to reduce dust mites.
• Wash bedding regularly in hot water.
• Limit outdoor activity during high pollen seasons.

However, because most dogs are allergic to environmental triggers, complete avoidance is rarely possible. Instead, the goal is to control symptoms and prevent secondary infections, so your pet remains as comfortable as possible.

Living with Allergies

Allergies can be frustrating for owners and uncomfortable for pets. We understand that it can feel disheartening when the itching never seems to fully go away. However, with a consistent and compassionate management plan, most pets can lead happy, itch-free lives.

At McLaren Vale Veterinary Surgery, we’re committed to supporting you and your pet on this journey. We’ll help you understand your pet’s condition, guide you through treatment options, and develop a long-term plan that works best for both of you. Together, we can help your pet find lasting comfort, even when allergies are here to stay.