Introduction
Dog allergies are quite common, affecting around 10-15% of dogs. An allergy occurs when the immune system overreacts to a foreign substance that is typically harmless. This overreaction leads to an allergic response, causing symptoms like itchy skin, ear infections, digestive issues, and respiratory problems.
Allergies can develop at any age, though they often first appear between 1-3 years old. Some breeds are more prone to allergies than others. For example, dogs with skin folds like Shar-Peis and Pugs tend to be more susceptible. Allergies can significantly impact a dog’s quality of life if left untreated.
Figuring out the specific allergen is key in managing allergies. Common dog allergens include foods, fleas, environmental triggers like pollen or dust mites, and skin conditions like atopic dermatitis. Through testing and trial and error, pet owners can identify the allergen and take steps to minimize exposure and control symptoms.
Common Allergens
There are several common allergens that frequently cause allergic reactions in dogs. Some of the most common include:
Flea Saliva – Flea saliva is one of the most common allergens for dogs. When fleas bite and feed off your dog, they inject their saliva under the skin. This saliva contains proteins that can trigger an allergic reaction, causing intense itching, skin irritation, and inflammation.
Food Ingredients – Allergies to food ingredients are another very common cause of allergic reactions in dogs. Some ingredients like beef, dairy, chicken, lamb, fish, eggs, corn, wheat, and soy are frequent allergens. An allergy can develop to just one ingredient or multiple ingredients.
Dust Mites – Microscopic dust mites that live in carpets, bedding, upholstered furniture and other fabric materials are a prime source of indoor allergens for dogs. Dogs can be allergic to the mites themselves or proteins found in their fecal droppings.
Mold – Airborne mold spores, a common environmental allergen, can be a problem for dogs that are prone to allergies. Mold thrives in warm, humid environments. Dogs may react to mold from outdoors as well as indoor sources like basements, bathrooms or laundry rooms.
Symptoms
There are several symptoms that may indicate your dog has an allergy. Some of the most common allergy symptoms in dogs include:
Itchy skin – Allergies are a very common cause of itchy skin (pruritus) and irritated skin in dogs. The itchiness is often focused on the face, feet, ears, folds of the skin, and the underside.
Ear infections – Dogs with allergies frequently suffer from ear infections (otitis externa). The most common causes of ear infections are yeast, bacteria, and parasites. Allergies can allow these organisms to infect the ears by damaging the skin inside the ear.
Hair loss – Some dogs can experience hair loss, bald spots, and abnormal hair growth as a result of their allergies. The itching, scratching, and skin irritation lead to hair loss and skin damage.
Excessive licking/scratching – Dogs will often lick or scratch at the affected areas in an attempt to relieve their itchy skin. Excessive licking and scratching is a clear sign your dog may have an allergy.
Diagnosis
Diagnosing the specific allergy your dog has can be tricky, but vets use a process of elimination and testing to pinpoint the culprit. Here are some common diagnostic methods:
Process of elimination: Your vet will first rule out parasites like fleas or mites, food allergies, bacterial or yeast infections, and other common causes. Keeping a detailed log of your dog’s symptoms and possible exposures helps inform this process.
Blood tests: Your vet can run a blood test checking for allergen-specific antibodies, like the Heska Allercept Test. While not definitive, it helps identify likely allergens for further testing.
Intradermal skin testing: This is considered the most accurate way to diagnose allergies.Small amounts of suspected allergens are injected under your dog’s skin to check for a reaction. Allergens that cause a raised wheal confirm an allergy. This helps build a tailored allergen “vaccine.”
Flea Allergy
Fleas are a common cause of skin allergies in dogs. Flea allergy dermatitis, also known as flea bite hypersensitivity, is an allergic reaction to the saliva of fleas. When a flea bites your dog, it injects saliva under the skin. This saliva contains foreign proteins that can trigger an immune response in dogs that are hypersensitive or allergic to flea bites.
Dogs with flea allergies experience severe itching, irritation, and inflammation from flea bites. The most common symptoms include excessive scratching, red skin, hair loss, scabs, and hot spots. These reactions can start within minutes or hours after a single flea bite. The reactions are often focused around the hind end, base of the tail, abdomen, and inner thighs.
Flea allergy is diagnosed through a detailed history, physical exam, flea combing, and intradermal allergy testing. The main treatment involves strict flea control and prevention year-round using veterinarian-approved topical and oral flea medications. Reducing skin inflammation and itching can help provide relief. Your vet may recommend anti-itch shampoos, fatty acid supplements, antihistamines, steroids, or immunotherapy.
The most effective treatment for flea allergy is flea control. Killing adult fleas and preventing immature flea stages from developing can stop the vicious cycle of biting and allergy flare ups. Use flea prevention products on all pets in the household and treat your home and yard as well. With diligent flea control, most dogs experience significant improvement in their skin condition and quality of life.
Food Allergy
Food allergies are common allergens for dogs. The most frequent food allergens for dogs include:
- Beef
- Dairy
- Chicken
- Eggs
- Corn
- Wheat
- Soy
If you suspect your dog has a food allergy, an elimination diet trial is recommended. This involves feeding your dog a novel protein diet, with a protein source they have never eaten before, for 8-12 weeks. Examples of novel protein sources include:
- Venison
- Kangaroo
- Bison
- Rabbit
A hydrolyzed protein diet is another option. In this diet, proteins are broken down into small fragments so they are less likely to trigger an immune response. Hydrolyzed protein diets can allow you to gradually reintroduce regular foods to identify allergens.
It’s important to consult with your veterinarian before putting your dog on a novel protein or hydrolyzed protein diet trial to rule out other conditions and ensure it is nutritionally balanced.
Environmental Allergy
After fleas and food, environmental allergens are the next most common cause of allergies in dogs. Environmental allergies are often caused by inhaling allergens like pollen, dust mites, and mold spores. Dogs can also be allergic to certain materials or chemicals found around the home.
Some of the most common environmental allergen sources include:
House Dust Mites
Dust mites are tiny insects that live in fabrics, carpets, and bedding. They feed on skin cells shed by humans and pets. The mites themselves along with their feces and decaying bodies can trigger allergic reactions when inhaled. Keeping the home clean and dust-free can help reduce allergen levels.
Mold Spores
Mold spores are released into the air from mold growing in damp areas like basements, bathrooms, and under sinks. Inhaling the spores can cause respiratory symptoms in allergic dogs. Controlling moisture and proper ventilation helps prevent mold growth.
Treatment Options
Treatment focuses on avoiding or reducing exposure to environmental allergens whenever possible. This may involve vacuuming and dusting more frequently, washing bedding regularly in hot water, using HEPA air filters, and keeping the dog out of rooms with carpet. Medications can also help control allergy symptoms.
Atopic Dermatitis
Atopic dermatitis, also known as atopic eczema, is an itchy inflammation of the skin. It is one of the most common skin conditions in dogs. Atopic dermatitis is not contagious or life-threatening, but it can significantly impact a dog’s quality of life.
Symptoms
The most common symptoms of atopic dermatitis in dogs include:
- Itching, scratching, licking, and chewing, especially of the face, feet, ears, folds of the skin, and underarm regions
- Red, inflamed skin
- Hair loss
- Secondary skin infections
Symptoms often begin between 6 months and 3 years of age. They tend to be seasonal at first, flaring up in spring and summer, before often becoming year-round.
Treatments
Treatment options for atopic dermatitis in dogs include:
- Allergy testing and allergen avoidance
- Anti-itch shampoos and conditioners
- Topical steroids and other anti-inflammatory medications
- Oral steroids or other immunosuppressants
- Antibiotics for secondary infections
- Omega-3 fatty acids
- Allergen-specific immunotherapy (allergy shots)
Treatment is focused on reducing inflammation and itchiness, fighting infections, and avoiding triggers. A combination approach is often needed. Identifying and minimizing allergen exposure is key for long-term management.
Allergy Medications
There are several types of medications that can help treat allergies in dogs:
Antihistamines
Antihistamines like diphenhydramine (Benadryl) and hydroxyzine can help block the effects of histamine and reduce allergy symptoms like itching, sneezing, and skin irritation. They are available in both pill and liquid forms. Antihistamines provide short-term relief but do not treat the underlying cause of the allergy.
Corticosteroids
Corticosteroids like prednisone and dexamethasone help reduce inflammation associated with allergies. They are very effective at relieving allergy symptoms but can have significant side effects if used long-term, including increased thirst and urination, panting, weight gain, and liver problems.
Immunosuppressants
Immunosuppressant drugs like cyclosporine, oclacitinib, and Atopica® (cyclosporine) can suppress the immune system reaction that causes allergies. They are used for more chronic, severe cases of allergies when steroids are ineffective or cannot be used long-term. Side effects may include vomiting, diarrhea, and increased risk of infection.
Prevention
There are several steps you can take to help prevent and manage your dog’s allergies:
Flea Control
Flea control is imperative, even if your dog does not have flea allergy dermatitis. Fleas can trigger other allergies and skin issues. Use monthly spot-on or oral flea preventatives recommended by your veterinarian.
Treat your home and yard to kill any flea eggs and larvae. Vacuum frequently and wash your dog’s bedding weekly.
Dietary Management
If your dog has food allergies, your vet may recommend a hypoallergenic or novel protein diet trial. This involves feeding a prescription food with hydrolyzed protein or a protein source your dog has not eaten before, for 8-12 weeks to see if symptoms resolve.
Avoid table scraps or treats with ingredients your dog may be allergic to.
Reducing Allergens at Home
Limit exposure to environmental allergens by keeping your dog out of high pollen areas and not allowing them on furniture where they may come in contact with dust mites.
Bathe your dog regularly to remove allergens from their coat. An air purifier with a HEPA filter can also help reduce allergens at home.