Anaphylaxis is the term veterinarian use to describe an extremely severe allergic reaction. The state of anaphylaxis is caused by IgE antibodies binding to the antigen, causing the release of cytotoxic granules from basophils and mast cells. Serotonin and histamine are then released, causing clinical signs of respiratory, gastrointestinal and cardiovascular distress in a short period of time.

Anaphylaxis in cats is a life-threatening, immediate allergic reaction to anything injected or consumed. This severe type of allergic response can be caused by foods, medications, vaccines, and insect bites or stings. If your cat is suffering from anaphylaxis, he or she could develop symptoms of facial swelling, rapid heart rate, weak pulse, difficulty breathing, vomiting, and/or diarrhea. The clinical signs of anaphylaxis can appear in a matter of minutes after the allergen enters the body, leading to worsened symptoms of cold extremities, pale mucus membranes, shock, seizure, coma, and even death. There is no way to know if your cat will experience anaphylaxis when exposed to an otherwise harmless agent, but felines that have other known allergies are at a potential risk. Anaphylaxis in cats is always an extreme emergency situation that can result in rapid death, therefore seeking veterinary care is a must. 

Symptoms of Anaphylaxis can occur in a matter of minutes or take as long as an hour to appear in cats. The feline’s lungs are the first organ to be affected in most anaphylaxis cases, causing airway obstruction and difficulty breathing. This upper respiratory effect is usually accompanied by hypoxemia, hypotensive shock, and gastrointestinal signs such as defecation and vomiting. 

Common symptoms a cat owner is likely to note in a cat experiencing anaphylaxis include: 

Anaphylaxis in cats is caused by an extreme overreaction of the body’s immune system to an allergen. At some point in the feline’s life, she came into contact with the allergen element and it was at this point in time that the immune system perceived this harmless substance as a threat. The immune system created IgE, or antibodies, to bind to the antigen (harmful invader) and destroy them the next time the substance entered the cat’s body. The next time the feline is vaccinated, stung, or consumes that food product, the antibodies trigger basophil and mast cell receptors (types of white blood cells). The immunity cells respond by releasing cytotoxic granules that contain serotonin and histamine, creating the response we see as an allergic reaction.

The symptoms a feline is displaying as she has been presented to the clinic will give the veterinarian a direct diagnosis of anaphylaxis. The cat will be admitted to emergency life support care immediately. Once the cat is stabilized, the doctor will then proceed to conduct diagnostic tests to determine the cause of the severe allergy, if it is not already known. Finding the source of a severe allergy will require a review of your cat’s medical history and paying close attention to the medications she is currently on and any vaccinations she has recently received. It is at this time that you should report any changes in your cat’s diet, including any treats or table scraps given in the last 24 hours. 

To diagnose a contact allergy, veterinarians can use intradermal skin testing or serologic testing for the allergen. However, is anaphylaxis cases, routine allergy testing proves inefficient compared to clinical findings. 

Anaphylaxis in cats is an immediate emergency situation and is treated promptly with life supportive intravenous fluids in combination with oxygen. Epinephrine is a common drug used in feline anaphylaxis situations to increase blood pressure and open the feline’s airways.  Depending on your cat’s condition, the veterinarian may also choose to use a bronchodilator inhalant, antihistamine drugs, and glucocorticoids to attend to the symptoms of an allergic reaction. Your cat will require monitoring for the next couple days in the hospital and will be released once she is stable.  

The prognosis for anaphylaxis in cats varies, based on when the reaction was noted by the owner, how prompt treatment was received and how severe the feline allergic reaction was. For cats that received immediate emergency care before the anaphylaxis reaction caused the feline to go into shock or coma, the prognosis is relatively positive. There is no way of knowing or preventing anaphylaxis in your cat, but if the feline has a history of allergies, pet owners can take precautions. Talk to your veterinarian about your cat’s allergies and what other cat owners in the same situation have done to prevent anaphylaxis from reoccurring.