Anaphylaxis in cats – signs and what to do

Updated 2026-09-30 · 1 sources

Based on: PDSA

See a vet now

This is an emergency – contact your vet or the nearest emergency vet right now. Anaphylaxis is a severe allergic reaction in cats.

What to do now

What you can do now

  1. Contact your vet now.
  2. Note when it started, how often it happens and what else you see.
  3. Take a photo or short video to show the vet.
  4. Let your cat rest somewhere calm.
  5. Keep fresh water available.

Don't

  • Do not give any human medicine.
  • Do not wait if it gets worse.

What it is

Severe allergic reactions can be life threatening.[1] Common triggers of allergic reactions in cats include insect stings, snake venom and certain medications.[1]

Signs

  • Swelling and redness around the affected area
  • Itching
  • Drooling
  • Rashes or spots
  • Severe swelling to the lips and face
  • Breathing problems
  • Limping if the foot or leg is affected
  • Vomiting and diarrhoea
  • Collapse

Causes and risk factors

  • Insect stings
  • Snake venom
  • Certain medications

How vets treat it

  • Steroids
  • Fluids through a drip
  • Medication
  • Anti-inflammatories
  • Hospitalisation

What the experts say

“Overview. Allergic reactions range from mild to severe and in some cases, can be life threatening. Cats can have an allergic reaction to almost anything, but the most common triggers include insect stings, snake venom and certain medications.”

If your pet is struggling to breathe, has collapsed, is having a seizure or can't stand up: go to the nearest vet now.

Not sure how serious it is?

OkPaw asks a few quick questions about your pet and tells you in 30 seconds whether it can wait. Free on Google Play for Android.

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Common questions

Can anaphylaxis be life threatening?

Yes. Severe allergic reactions can be life threatening.[1]

What signs can an allergic reaction cause in a cat?

Signs can include swelling and redness, itching, drooling, rashes or spots, breathing problems, vomiting and diarrhoea, and collapse.[1]

How may a vet treat a severe allergic reaction?

A cat with a severe allergic reaction may need intensive care in a veterinary hospital.[1]

Sources

  1. PDSA

How this page was made: written with the help of AI from the sources below, then checked claim by claim against those sources. Urgency levels follow OkPaw’s fixed safety rules. It is guidance, not a diagnosis. How we write our pages

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