The short answer
Tree pollen. Ontario’s tree pollen season kicks off in April, and dogs with seasonal allergies react through their skin rather than their sinuses. If the itching started when the weather warmed up, that timing is not a coincidence.
Why spring specifically
Birch, poplar, alder, and maple trees start releasing pollen in southern Ontario as early as late March. By mid-April, pollen counts are high enough to trigger symptoms in sensitive dogs. This first wave runs through May, then grass pollen picks up in June.
Your dog doesn’t have to be rolling in fields to be affected. Pollen is airborne. It settles on their coat, gets between their toes, and sticks to their belly when they lie on the lawn. Even a short walk near Sixteen Mile Creek or through your own backyard is enough exposure during peak days.
If your dog was fine all winter and suddenly can’t stop scratching, spring pollen is the most likely explanation. Here’s a full breakdown of which months are worst.
What to look for
The classic spring allergy pattern in dogs involves itchy paws (lots of licking and chewing), red or inflamed skin on the belly and inner legs, recurring ear infections, and head shaking. You might also notice your dog rubbing their face on the carpet or furniture.
Constant paw licking is one of the most reliable early signs. If you’re seeing that combined with the spring timing, allergies should be on your radar.
One thing to rule out: ticks become active at the same time in Ontario, and tick irritation can look similar at first glance. Check your dog for ticks after walks in wooded or grassy areas, and make sure tick prevention is current.
Quick relief at home
Wipe your dog’s paws and belly with a damp cloth after every outdoor walk. This removes pollen before it has time to cause a reaction. Wash their bedding more often during pollen season, and consider running an air purifier in the rooms where they spend the most time.
A cool bath with colloidal oatmeal shampoo can calm inflamed skin in the short term. Avoid hot water, which makes the itching worse.
If home measures aren’t enough, Benadryl may take the edge off mild cases, but check with your vet before giving it — dose, drug interactions, and underlying conditions matter. Most dogs with real spring allergies need something stronger from the vet anyway. Apoquel and Cytopoint are the current front-line treatments.
Key takeaways
- Spring itching in dogs is almost always tied to tree pollen, which peaks in April and May in Ontario.
- Dogs react to pollen through their skin. Watch for paw licking, belly redness, and ear infections.
- Pollen is airborne. Your dog doesn’t need direct contact with trees to be affected.
- Wiping paws and belly after walks is the simplest effective measure.
- Spring is also tick season in Ontario. Rule out ticks as a cause and keep prevention current.
References
- PetMD. “Pollen Allergies in Dogs: Symptoms and How to Treat Them.” petmd.com
- VCA Animal Hospitals. “Allergies in Dogs.” vcahospitals.com
- Kleenex Canada. “Pollen Calendar: Types of Pollen by Month.” kleenex.com