Action Plan: How to Help Your Pet During an Allergic Reaction

Your pet’s face is swollen, they’re pawing wildly at their muzzle, and you can see obvious stress signs. You realize they’re having an allergic reaction, but you don’t know what to do.

First, take a deep breath. Then, follow this allergic reaction action plan from the All Creatures Animal Hospital team.

What is an allergic reaction in pets?

Your pet’s immune system is responsible for defending their body against harmful viruses, bacteria, and diseases, but sometimes the immune system is provoked by harmless triggers such as insect bites, food proteins, and vaccines. After the pet is first exposed to a perceived threat, their immune system develops a strong, targeted defense that includes antibodies, histamine, and inflammatory mast cells, and the next time your pet encounters the same allergen, their immune system instantly dispatches these components. This creates a dramatic, sometimes instantaneous, reaction.

Allergic reactions in pets can range from chronic and irritating (e.g., seasonal, environmental, and food allergies) to sudden and severe. In this article, we focus on sudden (i.e., acute) allergic reactions.

Anaphylaxis: An allergic emergency for pets

As in people, most allergic reactions in pets are local (i.e., confined to a small body area), self-limiting, and are uncomfortable, but often temporary and benign (i.e., harmless). However, some pets can experience an immediate, severe, and potentially life-threatening reaction (i.e., systemic anaphylaxis or anaphylactic shock). Systemic anaphylaxis is a rapid condition with widespread swelling that can obstruct the airway and cause respiratory distress. Complications can also include hypotension (i.e., low blood pressure), which can compromise circulation. 

Less severe but still irritating anaphylactic reactions include tissue swelling, itching, and hives or raised bumps (i.e., wheals) on the skin. 

What causes acute allergic reactions in pets?

Your pet may be having an acute allergic reaction if they were recently exposed to common triggers (i.e., allergens or antigens), such as:

• Vaccines
• Food proteins
• Insect bites or stings 
• Medications
• Topical flea and tick medications
• Shampoos or sprays (e.g., dog flea shampoo or spray applied to a cat)
• Chemicals

Action plan: What to do if your pet is having an allergic reaction

Knowing how to respond to an allergic reaction can, at the least, minimize your pet’s discomfort and distress—and may save their life. If you think your pet is experiencing an allergic reaction, follow this three-step action plan.

Note, if your pet is in respiratory distress (e.g., gasping, wheezing, or has blue, grey, or purple gums), immediately transport them to All Creatures Animal Hospital or the nearest veterinary emergency center.

• Step 1: Stay calm — Your pet can sense your worry and stress, which may increase their panic and make them more difficult to care for, restrain, or transport. Take deep breaths as necessary, and stay focused on helping your pet.
• Step 2: Assess the situation — Evaluate your pet’s clinical signs to determine if their condition is an allergic reaction. Acute allergic reaction signs vary, but may include:

• • Facial swelling, especially around the eyes, muzzle, ears, and throat
  • Localized swelling (e.g., a paw)
  • Intense itching
  • Hives or raised bumps
  • Red inflamed skin
  • Vomiting and diarrhea
  • Difficulty breathing
  • Blue, grey, or purple gums and tongue
• Step 3: Take action — If your pet is struggling to breathe, immediately transport them to All Creatures Animal Hospital or the nearest veterinary facility. Pets with significant muzzle, throat, or facial swelling need a veterinarian’s evaluation, especially if they recently were vaccinated. Although facial swelling doesn’t always precede anaphylaxis and may resolve on its own, veterinary intervention can ease discomfort, reduce inflammation, and monitor your pet for worsening signs.

If your pet’s allergic reaction appears limited to the skin or localized to a specific body region, monitor your pet for the next 24 hours. If they seem uncomfortable or excessively itchy, contact our team to discuss at-home treatment options, such as oral diphenhydramine (i.e., Benadryl). Never give your pet any medications without veterinary approval.

Prevent or minimize your pet’s risk for future allergic reactions

Allergic reactions can occur in response to any substance in your pet’s environment, which makes prevention impossible. However, if your pet is prone to hypersensitivity reactions, several preventive measures are available that will minimize their risk or reduce the severity of their immune system’s response.

• Notify your pet’s care team — Inform your veterinarian and any other pet care personnel (e.g., groomers, trainers, boarding kennel attendants) about your pet’s allergies. 
• Speak with your veterinarian about your pet’s vaccination schedule — Your veterinarian may recommend single-vaccine appointments spread out over several weeks, or pre-medicating your pet with injectable diphenhydramine to block the immune system’s response.
• Use veterinarian-recommended preventives — Follow label instructions and ensure you use only feline products for cats
• Keep your dog on-leash in unfamiliar outdoor areas — This will prevent unpleasant encounters with stinging insect nests and hives.
• Maintain a pet first aid kit — Stock your kit with pet-safe hydrocortisone cream or aloe vera gel for stings and topical irritations, and light bandaging material to deter your pet from licking or chewing. Include diphenhydramine tablets, with your pet’s specific dose, if approved by your veterinarian. 

Allergic reactions can be frightening for pets and their owners, but knowing how to respond can help you stay calm and ensure your companion receives the care they need. If your pet is experiencing an allergic reaction or similarly concerning signs, contact All Creatures Animal Hospital, a Cara Family Neighborhood Vet.