Spring Dog Allergies in Colorado: Signs, Causes, and How to Get Relief

Colorado springs to life every year with blooming wildflowers, budding cottonwood trees, and warming temperatures — and for millions of dogs across the state, that seasonal shift brings weeks of relentless itching, sneezing, and discomfort. Spring allergy season in Colorado is no small inconvenience for pets. It can significantly affect your dog’s quality of life if you don’t know what to look for or how to respond.

If your dog has been scratching more than usual, rubbing their face on the carpet, or dealing with recurring ear infections every spring, seasonal allergies may be the culprit. Understanding what triggers these reactions in Colorado’s unique climate — and what you can actually do about it — makes a real difference for your dog’s comfort and your peace of mind.

When Does Spring Allergy Season Start for Dogs in Colorado

Colorado’s spring allergy season typically begins earlier than most pet owners expect. In lower-elevation areas like Denver, Colorado Springs, and the Front Range corridor, tree pollen starts circulating as early as late February or early March. By April and May, grass pollen joins the mix, and the season can stretch well into June depending on elevation and weather patterns.

The state’s variable climate adds another layer of complexity. A late snowstorm in April can temporarily suppress pollen counts, offering your dog brief relief, but warm spells that follow often trigger a rapid surge in airborne allergens. In higher-elevation mountain communities, allergy season may start a few weeks later but can still be intense during peak bloom periods.

Key Insight: Colorado’s dry, windy conditions are particularly problematic for allergic dogs. Low humidity keeps pollen particles airborne longer, increasing your dog’s exposure during outdoor time.

Cottonwood trees are one of the most notorious springtime offenders in Colorado. Their fluffy white seeds fill the air from late April through June across much of the Front Range, and while the cotton itself isn’t technically an allergen, it carries pollen and mold spores that absolutely are. If your dog’s symptoms spike during cottonwood season, that timing is not a coincidence.

What Causes Dog Allergies in Spring in Colorado

Spring allergies in dogs are almost always triggered by environmental allergens — substances your dog inhales, contacts through their skin, or picks up on their paws during outdoor activity. In Colorado, several specific allergens are especially prevalent during the spring months.

Tree pollen is the dominant trigger in early spring. Species like cottonwood, elm, ash, juniper, and oak release massive quantities of pollen from late winter through late spring. Grass pollen follows, with Kentucky bluegrass, Timothy grass, and Bermuda grass becoming significant contributors by May and June. Mold spores also increase in spring as snow melts and organic debris becomes wet and begins to decompose.

• Tree pollen: Cottonwood, elm, ash, juniper, and oak are primary culprits on the Front Range
• Grass pollen: Kentucky bluegrass and Timothy grass peak in May and June
• Mold spores: Snowmelt creates ideal conditions for outdoor mold growth in spring
• Dust mites: Increased indoor activity during early spring can worsen dust mite exposure
• Weed pollen: Some early-blooming weeds begin releasing pollen in late March

These allergens trigger what veterinarians call canine atopic dermatitis — an inflammatory skin condition caused by an overactive immune response to environmental substances. Unlike humans, whose allergies primarily cause respiratory symptoms, dogs tend to express their allergic reactions through their skin. That’s why itching, not sneezing, is usually the first and most prominent sign.

Important Note: Dogs can develop new allergies at any age. Even if your dog sailed through previous spring seasons without issue, a new sensitivity can emerge as their immune system changes over time.

Signs Your Dog Has Spring Allergies in Colorado

Recognizing the signs of spring allergies early gives you a much better chance of managing your dog’s discomfort before symptoms escalate. The signs can be subtle at first, but they tend to follow a predictable pattern that coincides with rising pollen counts.

Excessive scratching is the most common and recognizable symptom. Your dog may scratch at their face, ears, belly, armpits, or paws — areas where allergens make direct contact with thinner, more sensitive skin. Paw licking and chewing is another hallmark sign, often resulting in rust-colored staining on the fur between the toes from saliva contact.

Recurring ear infections that flare up every spring are a particularly telling sign in allergic dogs. Allergies disrupt the skin’s natural barrier, creating conditions that allow yeast and bacteria to thrive in the ear canal. If your dog has been treated for ear infections multiple times and the problem keeps returning each spring, allergies are very likely the underlying cause.

Common Mistake: Many pet owners treat the ear infection itself without addressing the underlying allergy driving it. This leads to a frustrating cycle of recurring infections that won’t fully resolve until the root cause is managed.

Which Dog Breeds Are Most Prone to Spring Allergies

While any dog can develop seasonal allergies, certain breeds have a significantly higher genetic predisposition to atopic dermatitis. If your dog falls into one of these categories and lives in Colorado, proactive allergy management during spring is especially worthwhile.

Golden Retrievers and Labrador Retrievers are among the most commonly affected breeds, with studies suggesting that up to 30% of these dogs develop some form of environmental allergy during their lifetime. West Highland White Terriers, Bulldogs, and French Bulldogs are also highly prone, partly due to their skin fold anatomy, which traps moisture and allergens. Boxers, Cocker Spaniels, and Shih Tzus round out a list of breeds that veterinary dermatologists frequently see for atopic skin disease.

• Golden Retriever — High genetic predisposition; often develops allergies between ages 1–3
• Labrador Retriever — Commonly affected; skin and ear symptoms are typical presentations
• West Highland White Terrier — Particularly prone to atopic dermatitis; symptoms often severe
• Bulldog and French Bulldog — Skin folds increase allergen contact and moisture retention
• Boxer — Known for environmental sensitivities; facial skin folds contribute to symptoms
• Cocker Spaniel — Ear anatomy makes them especially vulnerable to allergy-related infections
• Poodle and Doodle mixes — Increasingly common in Colorado; moderate to high allergy risk
• Shih Tzu — Sensitive skin and facial fur increase allergen exposure around eyes and nose

Mixed-breed dogs are not immune. Genetics play a role, but any dog with a family history of skin disease or allergies — regardless of breed — carries elevated risk. If you’re unsure about your dog’s breed composition, a DNA test combined with a veterinary skin evaluation can help clarify their allergy risk profile. You can also review breed-specific information relevant to Colorado dog owners to better understand how breed characteristics intersect with local conditions.

How Vets Diagnose Seasonal Allergies in Dogs in Colorado

Getting an accurate diagnosis is one of the most important steps you can take for your allergic dog. Many conditions mimic allergy symptoms — including mange, ringworm, flea infestations, and food sensitivities — and treating the wrong cause wastes time while your dog continues to suffer.

Your veterinarian will typically begin with a thorough physical examination and a detailed history of when symptoms occur, how long they last, and whether they follow a seasonal pattern. The seasonal timing of symptoms — specifically whether they worsen each spring and improve in fall or winter — is one of the strongest indicators of environmental allergies rather than food-related issues.

Pro Tip: Keep a symptom journal for your dog starting in late February. Note the dates when scratching increases, when ear infections appear, and when symptoms peak. This timeline is extremely useful for your vet when building a diagnosis.

For dogs with moderate to severe or persistent symptoms, your vet may refer you to a veterinary dermatologist for intradermal allergy testing — the gold standard for identifying specific environmental allergens. Small amounts of common allergens, including regional Colorado pollens like cottonwood and bluegrass, are injected just under the skin. A positive reaction (a raised wheal) identifies which specific allergens your dog is reacting to.

Blood-based serology tests (RAST or ELISA testing) are another option and can be performed by your regular vet without a specialist referral. While slightly less precise than intradermal testing, they provide actionable information about your dog’s specific sensitivities and can guide the development of a customized allergy immunotherapy plan.

How to Treat Spring Allergies in Dogs in Colorado

Treatment for spring allergies in Colorado dogs has advanced considerably over the past decade. You now have more targeted, effective options than ever before, ranging from daily medications to long-term immunotherapy that can reduce your dog’s sensitivity to specific allergens over time.

For immediate symptom relief, veterinarians most commonly prescribe one of the following approaches:

1. Apoquel (oclacitinib): A once-daily oral medication that targets the specific itch pathway involved in atopic dermatitis. It works quickly — often within 24 hours — and is well-tolerated by most dogs for long-term use.
2. Cytopoint (lokivetmab): A monthly injectable biologic that neutralizes the protein responsible for triggering itch signals. It’s particularly useful for dogs who have difficulty taking oral medications or who need consistent long-term control.
3. Antihistamines: Over-the-counter options like cetirizine (Zyrtec) or diphenhydramine (Benadryl) can provide mild relief for dogs with less severe symptoms, though their effectiveness varies significantly between individual dogs.
4. Corticosteroids: Short-term steroid use (prednisone) can quickly reduce inflammation during acute flare-ups, but long-term use carries significant side effects and is generally reserved for severe cases or short-term relief.
5. Allergen-specific immunotherapy (ASIT): Customized allergy shots or sublingual drops formulated from your dog’s specific allergen profile. This is the only treatment that addresses the underlying immune dysfunction rather than just managing symptoms.

Medicated shampoos and topical treatments also play an important supporting role. Regular bathing with a veterinary-formulated shampoo removes pollen and allergens from your dog’s coat and skin, reducing the cumulative allergen load that drives symptoms. Omega-3 fatty acid supplements support the skin’s natural barrier function and can reduce the severity of inflammatory reactions over time.

Pro Tip: Ask your vet about combining Apoquel or Cytopoint with regular medicated baths and an omega-3 supplement. This multi-pronged approach often achieves better symptom control than any single treatment alone.

How to Reduce Your Dog’s Exposure to Spring Allergens in Colorado

Medication manages your dog’s immune response, but reducing allergen exposure in the first place is equally important — and often overlooked. In Colorado’s open landscape, complete avoidance isn’t realistic, but strategic management can significantly lower your dog’s daily allergen burden.

Timing your dog’s outdoor activity around daily pollen counts is one of the most effective strategies. Pollen levels in Colorado are typically highest in the morning between 5 a.m. and 10 a.m. and on dry, windy days. Scheduling walks for late afternoon or after rain can meaningfully reduce your dog’s pollen exposure. Colorado’s National Weather Service Boulder forecast office and local weather apps often include pollen count data during peak season.

• Wipe your dog’s paws, belly, and face with a damp cloth immediately after outdoor time
• Bathe your dog once or twice weekly with a vet-recommended shampoo during peak pollen season
• Keep windows closed during high pollen periods and use air conditioning when possible
• Wash your dog’s bedding weekly in hot water to remove accumulated pollen and dust
• Use a HEPA air purifier in rooms where your dog spends the most time
• Avoid walking your dog through fields of blooming wildflowers or tall grass during peak season
• Consider dog boots for walks during cottonwood season to reduce paw contact with allergens

Your own clothing and shoes can also carry pollen indoors. Removing shoes at the door and changing clothes after spending time outdoors during high-pollen days reduces the amount of allergen you inadvertently bring into your dog’s environment. These small habits add up to a meaningfully lower allergen load over the course of a long Colorado spring.

Key Insight: Colorado’s spring wildlife activity also increases during allergy season. Dogs exploring trails may encounter insects like bees or wasps that can cause additional skin reactions — making it worth knowing what’s active in your area during spring hikes.

Indoor air quality deserves special attention during Colorado’s spring months. Replace HVAC filters more frequently — every 30 to 45 days during peak pollen season rather than the standard 90-day cycle. This prevents your home’s ventilation system from recirculating the same pollen your dog is trying to escape outdoors.

When to See a Vet About Your Dog’s Spring Allergies in Colorado

Knowing when home management is enough and when professional veterinary care is necessary can save your dog from prolonged discomfort and prevent minor allergy symptoms from developing into more serious secondary infections.

You should schedule a veterinary appointment if your dog’s scratching is intense enough to cause skin damage — open sores, hair loss, or bleeding are clear indicators that the situation has moved beyond what over-the-counter remedies can address. Recurring ear infections, especially if they appear every spring, warrant a vet visit to determine whether allergies are the driving cause and to prevent permanent damage to the ear canal.

Seek prompt veterinary care if you notice any of the following:

• Skin that is hot, swollen, oozing, or showing signs of infection
• Ear infections that return within weeks of completing treatment
• Symptoms that don’t improve after two weeks of antihistamine use
• Significant behavioral changes — restlessness, sleep disruption, or loss of appetite due to discomfort
• Eye discharge that is thick, yellow, or green rather than clear and watery
• Facial swelling or hives that appear suddenly (these may indicate an acute allergic reaction requiring immediate attention)

Important Note: Sudden facial swelling, difficulty breathing, or collapse after outdoor exposure can indicate anaphylaxis — a life-threatening allergic reaction. This is a veterinary emergency. Contact an emergency vet clinic immediately if these signs appear.

For dogs with moderate to severe seasonal allergies, don’t wait for symptoms to become severe before consulting your vet. Starting prescription allergy management — whether Apoquel, Cytopoint, or immunotherapy — before peak pollen season gives the treatment time to work and often prevents the worst of the seasonal flare. Many Colorado veterinarians recommend scheduling a pre-season allergy consultation in late January or February, before cottonwood and grass pollen begin to dominate the air.

Colorado’s spring season is one of the most beautiful times of year in the state, and your dog deserves to enjoy it comfortably. With the right combination of veterinary care, environmental management, and attentive monitoring, most allergic dogs can move through spring with far less suffering — and far more tail-wagging — than their untreated counterparts. Working closely with your vet and staying ahead of pollen season is the most reliable path to keeping your dog comfortable from the first warm day through the last frost of a Colorado spring.