How pets get stung
Pets receive the majority of their wasp stings in two scenarios: investigating a nest entrance (nose-first, which accounts for the facial swelling that is the most common presentation seen in Metro Vancouver veterinary clinics) and snapping at individual workers during the late-summer scavenging phase. Dogs are more likely to snap at wasps flying near their food bowl or near the garbage — the same scavenging behavior that draws yellowjackets to outdoor dining areas draws them to outdoor pet food dishes. Cats occasionally catch and eat wasps, receiving stings inside the mouth. The sting-in-mouth scenario is the most medically serious for pets, for the same reason it's serious in humans — local swelling near the airway.
What a normal reaction looks like in dogs
A single wasp sting in a dog typically produces immediate pain behaviour (whining, pawing at the sting site), followed by a visible raised welt and localized swelling that develops over 30-60 minutes. Facial stings produce more dramatic-appearing swelling — a nose or muzzle sting on a 30 kg dog can produce visible facial swelling within an hour that looks alarming but is typically a local reaction that resolves in 24-48 hours without treatment. The dog will be uncomfortable and may have reduced appetite. Benadryl (diphenhydramine) at 1 mg per kilogram of body weight is the standard home management for local reactions — check with your vet before administering, and use plain diphenhydramine (not the combination antihistamine-decongestant products that may be toxic to dogs).
| Reaction type | Signs | Home management | Call vet? |
|---|---|---|---|
| Local reaction | Whining, pawing at sting site, small welt. Dog is alert and active. | Ice 10 mins, diphenhydramine at vet-approved dose. Monitor 2 hrs. | If no improvement in 2 hours |
| Large local reaction | Visible swelling extending beyond sting site, facial puffiness (from nose/muzzle sting). Dog alert. | Diphenhydramine; keep calm. Monitor closely. | Yes — call and describe for guidance |
| Anaphylaxis — early | Vomiting or diarrhea (common early pet anaphylaxis sign), pale gums, agitation, hives on skin (visible where hair is thinner). | Call vet immediately. Anaphylaxis in dogs is often gastrointestinal first. | Yes — immediately |
| Anaphylaxis — severe | Collapse, extreme weakness, loss of consciousness, laboured breathing, cold limbs. | Emergency vet now. Do not wait. | Yes — 24hr emergency vet now |
| Multiple stings (10+) | Any presentation — toxic reaction from venom volume, not allergy | Emergency vet regardless of current appearance | Yes — immediately |
The cat sting scenario: different signs, same urgency
Cats present differently than dogs after wasp stings, and the presentation is often missed. Cats typically become quiet and withdrawn rather than whining — they retreat to a hiding spot, reduce activity, and may stop eating. A cat that was active and outdoors and is now hiding under the bed after being in the garden during yellowjacket season warrants investigation. Check the mouth and paw pads (common sting sites for cats) for swelling. Cats also have a higher rate of severe anaphylaxis per sting event than dogs — the reasons aren't fully characterized, but feline immune response to venom proteins is more likely to produce systemic reaction. A cat stung inside the mouth should be seen by a vet immediately regardless of current symptoms.
Reducing pet sting risk in Metro Vancouver yards
- Move outdoor pet food dishes inside after feeding — food left in outdoor bowls is an August yellowjacket scavenging target.
- Keep dogs on leash when investigating new areas during wasp season (July-October) — dogs are nose-first investigators and are likely to put their face into a ground-nest entry.
- Do not allow pets to snap at or play with wasps — this behaviour results in mouth or throat stings, the highest-risk sting scenario.
- Treat any active wasp nest on the property promptly — pets cannot receive EpiPens (epinephrine is used by vets in anaphylaxis but requires injection, not self-administration).
- Know your nearest 24-hour emergency veterinary clinic before wasp season begins, not after a sting event.
If a pet encounters a wasp nest rather than a single wasp — the scenario where a dog follows a ground-nest entry and receives dozens of stings — treat it as a veterinary emergency regardless of current presentation. Toxic venom reactions in pets from multiple stings are not the same as allergic reactions; they're organ-load events that may not manifest symptoms immediately but can produce kidney and liver damage over 24-72 hours. Multiple-sting events in pets warrant same-day veterinary assessment even if the pet appears normal. See also [wasp-allergic-reaction](/guide/wasp-allergic-reaction) for the human sting management parallel.