Seasonal Allergies in Pets: Managing Pollen, Grass, and Mould Triggers

If your dog or cat becomes noticeably itchier during certain months of the year, seasonal environmental allergies are a likely cause. Unlike food allergies (which cause year-round symptoms) or flea allergies (which peak in warm months but relate to parasites rather than plants), seasonal allergies follow a predictable calendar linked to pollen and mould cycles.

"One of the first things I ask owners of itchy pets is: does the itching get worse at certain times of year? If there is a clear seasonal pattern — worse in spring, better in winter — we are almost certainly dealing with a pollen or mould allergy. This is valuable diagnostic information." — Dr. Sarah Chen, DVM

UK and Northern Europe

• February–May: Tree pollens (birch, oak, ash, hazel)
• May–September: Grass pollens (ryegrass, timothy) — the peak allergy season for most pets
• June–October: Weed pollens (nettle, dock, plantain) and mould spores

US

• February–May: Tree pollens (cedar, maple, oak, birch)
• May–September: Grass pollens (bermuda, bluegrass, fescue)
• August–November: Ragweed (the #1 weed allergen) and mould

Keeping a diary of when your pet's symptoms flare helps your vet identify likely triggers. For a full overview of how environmental allergies work, see our guide on atopic dermatitis in dogs.

Seasonal allergy symptoms in pets overlap with other allergic conditions, but the timing and pattern provide important clues.

In Dogs

• Itchy paws: Excessive licking of all four paws — especially after walks on grass. Paws may appear stained brown-red from saliva.
• Itchy face and ears: Rubbing the face on carpet, furniture, or grass. Recurrent ear infections (redness, head shaking, odour) during allergy season.
• Belly and armpit redness: Pink or red skin on the belly, groin, and armpits — areas with thin skin that contacts allergens when lying on grass.
• Generalised scratching: More scratching, rubbing, and restlessness than usual, corresponding to high pollen days.
• Eye discharge: Some dogs develop watery or slightly mucousy eye discharge during pollen season — the closest equivalent to human hay fever eyes.

In Cats

• Over-grooming: Increased licking leading to hair loss on the belly, inner legs, or flanks — often noticed as thinning fur rather than bald patches.
• Head and neck scratching: Scabby, raw patches around the ears, head, and neck.
• Miliary dermatitis: Small crusty bumps along the back.
• Sneezing: More common in cats than dogs — some pollen-allergic cats do sneeze seasonally.

If symptoms worsen on windy, warm days and improve on rainy days or when your pet stays indoors, pollen allergy is strongly suspected.

While you cannot eliminate pollen exposure entirely, practical environmental management can significantly reduce the allergen load on your pet and may reduce the need for medication.

After Every Outdoor Trip

• Paw rinse or wipe: Rinse paws with water or wipe with a damp cloth after every walk. This removes pollen that would otherwise be licked off (ingested) or tracked onto bedding. Some owners keep a shallow tray of water by the door for a quick paw dip.
• Body wipe-down: For dogs with significant belly and chest contact with grass, wipe the underside with a damp microfibre cloth or hypoallergenic pet wipe.
• Regular bathing: A weekly bath with a gentle, soothing shampoo (oatmeal-based or a vet-recommended medicated shampoo) removes accumulated allergens from the coat and skin.

Timing Outdoor Activities

• Walk early morning or late evening when pollen counts are lower.
• Avoid walks immediately after grass has been mowed — this releases a burst of grass pollen and plant particles.
• On high pollen count days (check weather apps or pollen forecasts), consider shorter walks on paved paths rather than long grass walks.

Indoor Environment

• Keep windows closed during peak pollen hours (mid-morning to mid-afternoon).
• Use a HEPA air purifier in rooms where your pet sleeps.
• Wash pet bedding weekly in hot water.
• Vacuum with a HEPA filter vacuum regularly — carpets trap pollen brought in on shoes and clothing.

The treatment approach for seasonal allergies depends on the severity and duration of your pet's symptoms. Mild, short-season allergies may need only topical management, while severe, multi-season allergies benefit from systemic therapy.

Mild Seasonal Allergies

• Omega-3 fatty acid supplements: Start 4 to 6 weeks before the expected allergy season. Fish oil supplements at therapeutic doses (ask your vet for the correct dose) can reduce the severity of inflammatory responses.
• Antihistamines: Cetirizine (dogs and cats), chlorpheniramine (cats), or loratadine (dogs) can provide mild relief. Response rates are about 30 per cent, but they are safe and inexpensive.
• Topical therapy: Medicated shampoos and mousse products containing ceramides, phytosphingosine, or colloidal oatmeal soothe skin and strengthen the barrier.

Moderate to Severe Seasonal Allergies

• Oclacitinib (Apoquel): Can be started at the beginning of allergy season and stopped when the season ends. Fast-acting, effective, and well-tolerated by most dogs.
• Lokivetmab (Cytopoint): A monthly injection during allergy months. Particularly convenient for owners who prefer not to give daily tablets.
• Short courses of corticosteroids: For acute flares, a 5-to-10-day prednisolone course can provide rapid relief while other measures take effect.

Long-Term Solution

Immunotherapy (ASIT): For pets with severe, multi-season allergies, allergen-specific immunotherapy is the gold standard. Allergy testing identifies specific triggers, and a custom vaccine is formulated. Given as regular injections or daily sublingual drops, immunotherapy is the only treatment that can fundamentally change the immune system's response. See our comprehensive allergy guide for more details on all treatment options.

Not every itch during spring requires a vet visit, but certain signs indicate that professional intervention is needed.

See Your Vet If:

• Symptoms are severe or worsening: Intense scratching that disrupts sleep, causes visible skin damage, or does not respond to basic measures (bathing, antihistamines, paw wiping).
• Ear infections develop: Red, smelly, waxy ears or head shaking. Ear infections will not resolve without proper treatment and can become chronic if neglected.
• Skin infections appear: Pimples, pustules, hot spots, crusting, or an unusual odour from the skin. These require antibiotics or antifungals alongside allergy treatment.
• Symptoms affect quality of life: Your pet is visibly uncomfortable, sleeping poorly, off their food, or withdrawn.
• Over-the-counter treatments are not working: If antihistamines, bathing, and environmental management provide insufficient relief, prescription options like Apoquel, Cytopoint, or immunotherapy are likely needed.
• Symptoms extend beyond one season: If your pet now itches across multiple seasons or year-round, the condition may be progressing and requires a more comprehensive management plan.

Preparing for Your Vet Visit

Bring a symptom diary if possible: when itching started, which body areas are affected, whether it is worse after walks or at certain times of day, and what treatments you have tried. Photos of skin lesions taken at their worst are invaluable, as symptoms often look milder during the appointment. This information helps your vet develop the most targeted treatment plan.