Dog Allergies: Food, Environmental, and Seasonal

Why Your Dog Won't Stop Scratching

If your dog is itchy, you're not alone. Allergies affect an estimated 10-20% of all dogs, making them one of the most common reasons for vet visits. The tricky part is figuring out what your dog is allergic to, because the symptoms often look the same regardless of the cause.

Cooper went through a rough patch around age three, constant ear infections, paw licking that turned his fur rust-colored, and itchy skin that kept him (and me) up at night. It took us three months and an elimination diet to figure out he was sensitive to chicken. Yes, chicken, the most common protein in dog food. Once we switched, the difference was dramatic.

Food Allergies vs. Food Intolerance

First, an important distinction. True food allergies involve an immune system response and typically cause skin symptoms. Food intolerance involves the digestive system and usually causes gastrointestinal symptoms (vomiting, diarrhea, gas). Both are real, but they're different conditions that require different approaches.

Common Food Allergens

Despite what marketing might suggest, the most common food allergens in dogs are proteins, not grains:

• Beef, the most common food allergen in dogs
• Dairy products, second most common
• Chicken, very common, which is problematic because chicken is in everything
• Wheat, less common than proteins but still a documented allergen
• Soy, often used as a protein filler in lower-quality foods
• Lamb, was once used as a "novel protein" but has become common enough to cause allergies too
• Egg, found in many dog foods and treats

Diagnosing Food Allergies

Here's where it gets frustrating: there is no reliable blood or skin test for food allergies in dogs. Those allergy panel tests you can buy? Studies have shown they produce inconsistent, often inaccurate results. The only reliable method is an elimination diet trial:

1. Switch to a novel or hydrolyzed protein diet prescribed by your vet (not just a different brand from the pet store)
2. Feed ONLY that diet for 8-12 weeks. No treats, no table scraps, no flavored medications. Nothing except the prescribed food and water.
3. If symptoms improve, reintroduce the original food. If symptoms return, you've confirmed a food allergy.
4. Identify the specific allergen by reintroducing individual proteins one at a time, waiting 2 weeks between each.

It's a long process, and it requires serious discipline. One stolen treat or one well-meaning family member slipping your dog a bite of chicken can reset the entire trial.

Environmental Allergies (Atopic Dermatitis)

Environmental allergies are triggered by substances your dog breathes in or contacts through their skin. Unlike food allergies, environmental allergies often show a seasonal pattern, though in some dogs, they're year-round.

Common Environmental Allergens

• Pollen, tree, grass, and weed pollen (seasonal)
• Dust mites, year-round, often worse in winter when dogs spend more time indoors
• Mold spores, indoor and outdoor mold (seasonal and year-round)
• Dander, from other animals in the home
• Cleaning products, floor cleaners, laundry detergents, air fresheners
• Cigarette smoke
• Perfumes and scented products

Symptoms of Environmental Allergies

• Itchy skin, especially around the face, ears, paws, belly, and armpits
• Red, inflamed skin
• Chronic ear infections (recurrent, often yeasty)
• Paw licking and chewing (look for rust-colored staining on light-colored fur)
• Rubbing the face against furniture or carpet
• Hot spots (localized areas of infected, inflamed skin)
• Watery eyes
• Sneezing (less common than in humans, but it happens)

Seasonal Allergies

Seasonal allergies are technically a subset of environmental allergies, but they deserve special attention because the seasonal pattern provides useful diagnostic information:

• Spring: Tree pollen (oak, birch, cedar, pine)
• Summer: Grass pollen (Bermuda, timothy, bluegrass)
• Fall: Weed pollen (ragweed is a major culprit), mold from decaying leaves
• Winter: Dust mites, indoor mold, dry air irritation

If your dog's symptoms reliably appear and disappear with the seasons, that's a strong indicator of seasonal allergies. Keep a log of when symptoms flare, this information is invaluable for your vet.

Treatment Options

Treatment depends on the type and severity of your dog's allergies:

For Food Allergies

• Avoidance, once you identify the allergen through an elimination diet, simply avoid it. This is the most effective "treatment."
• Novel protein diets, venison, duck, rabbit, or fish-based foods that avoid the problematic protein
• Hydrolyzed protein diets, prescription foods where proteins are broken down small enough that the immune system doesn't react to them

For Environmental/Seasonal Allergies

• Apoquel (oclacitinib), a prescription medication that targets itch at its source. Fast-acting and effective for most dogs. Requires regular blood monitoring.
• Cytopoint, an injectable antibody treatment given every 4-8 weeks. Works differently than Apoquel and some dogs respond better to one than the other.
• Antihistamines, over-the-counter options like Benadryl, Zyrtec, or Claritin. Less effective than prescription options but worth trying. Always check with your vet for proper dosing.
• Immunotherapy (allergy shots), based on allergy testing, custom-formulated to desensitize your dog to specific allergens. Takes 6-12 months to work but can provide long-term relief.
• Medicated shampoos and wipes, help remove allergens from the skin and soothe irritation
• Omega-3 fatty acid supplements, support skin barrier function and can reduce inflammation

Home Management Tips

• Wipe your dog's paws and belly after outdoor walks
• Bathe your dog weekly during allergy season with a gentle, hypoallergenic shampoo
• Wash bedding in hot water weekly
• Use air purifiers with HEPA filters in rooms where your dog spends the most time
• Vacuum frequently (especially if you have carpets)
• Avoid walks during peak pollen hours (early morning and late afternoon)
• Consider a diet formulated for sensitive dogs to support skin health

When to See Your Vet

While mild, occasional itching is normal, you should see your vet if:

• Your dog is scratching, licking, or chewing constantly
• You notice hair loss, sores, or broken skin
• Ear infections keep coming back
• Symptoms are interfering with your dog's sleep or quality of life
• You see signs of secondary infection (pus, strong odor, hot/swollen skin)

Related Reading

Dealing with food sensitivities? Our guide to the best food for dogs with sensitive stomachs covers diet options in detail. For more on nutrition, check out our human foods dogs can eat guide. And if you're considering a dietary change, our article on how to switch dog food safely walks you through the transition process.