Allergies are common in dogs, and for pet owners, managing symptoms can be frustrating and confusing. Although some allergic dogs have hay-fever-like signs (e.g., irritated eyes or runny nose), most develop a problem with itchy skin or ears.
If your dog scratches, licks, or chews their skin or gets rashes and ear infections, an allergy may be to blame. Here are the most common types of dog allergies, symptoms that should make you suspicious of an allergy, and how to manage your dog’s condition with help from your veterinarian.
What are dog allergies?
Allergies in dogs happen when the immune system overreacts to a trigger, or allergen. The allergen may be something your dog inhales, eats, or touches. The immune system thinks the allergen is attacking the body, so it attacks back.
Allergens activate antibodies, which tell other cells to release inflammatory chemicals like histamines that cause redness, itching, and other signs of an allergic response. Repeated exposure to allergy triggers often makes them worse over time.
We don’t know why some dogs develop allergies and others don’t. Genes may play a role, as certain breeds seem predisposed. Allergies and immune health may be related to the gut microbiome, but we’re only beginning to scratch the surface of what this means for you and your pet.
Common dog allergies
Dogs can develop several types of allergies, and most allergic dogs have more than one. Many symptoms overlap, but a few key differences can help you and your veterinary team narrow down the possible causes.
There are four broad dog allergy types:
- Environmental
- Flea
- Food
- Contact
1. Environmental allergies
Environmental allergies (e.g., atopy or atopic dermatitis) are very common in dogs. Symptoms can be seasonal for dogs with pollens or grass allergies, or they could happen year-round for dogs with dust mite or mold allergies.
Common signs of envirnmental allergies in dogs include:
- itchy skin
- redness
- thickened or dark skin
- inflamed ears
- hair loss
- scabs or flaky, round spots
These symptoms commonly affect the feet, ears, belly, and armpits, and may cause secondary bacterial infections that look like pimples or rashes.
2. Flea allergy dermatitis
Flea allergies are also common in dogs, occurring because of a reaction to flea saliva that gets injected into their skin when fleas bite to feed. Importantly, it may take only one flea bite to trigger severe flea allergy dermatitis (FAD), so your dog can still have an allergy even if you never see fleas or signs of a flea infestation.
Flea allergy dermatitis can cause general itchiness like other environmental allergies, but it tends to have a few characteristic symptoms. They include:
- Extreme itchiness
- Scabs and hair loss concentrated on the lower back, tail base, and rear legs
- Recent flea exposure or flare-ups during peak flea season (mid to late summer)
Consistent, year-round flea prevention using approved veterinary products is the best way to manage this condition.
3. Food allergies
Food allergies are uncommon in dogs. For the unlucky few, food allergies can affect the skin in similar ways to environmental allergies or cause digestive system upsets. A true food allergy is different from food-responsive gastrointestinal conditions, such as inflammatory bowel disease or food sensitivities.
The most common food allergens for dogs are proteins, including beef, chicken, dairy, soy, and egg. It’s not a coincidence that the most common proteins used in dog food are also the most common food allergens—typically, a food allergy develops over time to ingredients in the food your dog already eats.
4. Contact allergies
With contact allergies, direct skin exposure to an irritant, such as grass, a topical flea product, or a household chemical, causes localized symptoms. Affected dogs might have a rash, redness, hives, or hair loss where the allergen was in contact with the skin, but the rest of their skin is unaffected.
Avoidance of the allergen is best, but when that is not possible, frequent bathing with gentle dog shampoo or hypoallergenic skin wipes may help remove allergens from the skin and coat and minimize reactions.
Symptoms of allergies in dogs
Allergy symptoms can vary from dog to dog and may change over time as sensitivity to allergens changes. Allergy symptoms overlap with those of other common skin conditions, such as parasites, bacteria, or yeast infections, and ringworm, a type of fungus.
Your veterinarian will use a combination of diagnostic tests and your pet’s history to determine if your pet has allergies, another skin condition, or a combination. Here is a list of possible allergy signs:
- Itching
- Recurrent ear infections
- Red or darkened skin
- Sneezing or runny eyes
- Hair loss
- Rust-colored staining on paws from licking
- Hives or bumps
- Recurrent vomiting or diarrhea
- Rashes, flaking, or scabs
- Foul-smelling skin or ears
- Greasy or dry skin
Diagnosing dog allergies
Dog allergy diagnosis can take time because no single test can provide a definitive answer. Your veterinarian will start with a physical exam and a review of your dog’s history, then recommend one or more of the following tests:
- Allergy testing (blood or skin testing) to identify environmental allergens
- Strict elimination diet for at least 8 to 12 weeks to detect food allergies
- Skin cytology to rule out bacterial infections or yeast overgrowth
- Skin scraping to look for skin mites (i.e., mange)
- Fungal cultures to look for ringworm
- Blood testing to check for hormonal imbalances
In some cases, your vet may refer you to a veterinary dermatologist for advanced testing and ongoing treatment.
Treatment options for dog allergies
Successful allergy treatment requires a close partnership between you and your dog’s veterinary team. It may take some time to determine your dog’s allergy pattern and triggers and to find what works best for them.
Some dogs need year-round allergy treatment or a special diet, while others need help only during specific seasons. All allergic dogs will have flare-ups of their symptoms from time to time, which is why a close relationship with your vet is essential.
Most dogs need a combination of therapies, which may include one or more of the following treatment options:
- Antihistamines to reduce mild itchiness or hives
- Apoquel or Cytopoint to target itching and inflammation in the skin
- Steroids or cyclosporine to control widespread inflammation
- Allergy shots (i.e., immunotherapy) to retrain the immune system
- Medicated shampoos and conditioners to control bacteria and yeast overgrowth
- Prescription diet or hydrolyzed, limited-ingredient, or nutritionist-formulated food
- Fatty acids and supplements to support a healthy skin barrier
- Year-round flea and tick control
- Home and lifestyle changes, such as air filters, dust mite covers, and frequent vacuuming and bathing
Once your veterinarian identifies the type of allergy your dog has, the focus shifts to long-term management. Dog allergies aren’t curable, but they are manageable with consistent care.
Living better with dog allergies
Dog allergies are frustrating for dogs and the people who love them. It can take time to find the best treatment plan, but sticking to your vet’s recommendations can make a big difference in comfort and quality of life.
Whatever your dog’s allergy type, diet and nutrition may play an important role in management. At JustFoodForDogs, we offer veterinary-prescribed and custom-formulated diets to meet your pup’s specific dietary needs. Additionally, our range of supplements and pre-packaged frozen and shelf-stable meals may help to support skin health and overall well-being.
This content is for informational use only and does not replace professional nutrition and/or medical advice, diagnosis, or treatment. It is not a substitute for and should not be relied upon for specific nutrition and/or medical recommendations. Please talk with your veterinarian about any questions or concerns.
“Flea Allergy Dermatitis in Dogs.” n.d. Vca_corporate. https://vcahospitals.com/know-your-pet/allergy-flea-allergy-dermatitis-in-dogs.
“Dogs and Cats Usually Manifest Their Allergies in Their Skin, Ears, Eyes, and Anal Glands (Ear Infections, Skin Infections, Etc.).” n.d. https://www.vetmed.ucdavis.edu/sites/g/files/dgvnsk491/files/inline-files/Allergies%20In%20Pets%20FINAL.pdf.
