Allergic Reactions in Cats and Dogs

Just like people, dogs and cats can have allergic reactions that can be mild or severe—but in all situations, you should contact your veterinarian for advice.

An allergic reaction is a hypersensitivity disorder of the immune system. In other words, the body reacts adversely to normally harmless environmental substances, which in this case are called “allergens.” In mild cases, your pet may develop redness around the lips and eyes, or hives. In the most severe situations, anaphylaxis may occur.

Anaphylaxis is a type of shock reaction that creates an emergency situation for you and your pet. It happens when he reacts negatively and severely to a normally nonharmful allergen. In extreme situations, anaphylaxis can lead to death, which is why it is critical that you call your veterinarian any time you suspect your pet is having an allergic reaction.


Symptoms of anaphylaxis include: 

The onset of a severe allergic reaction can be immediate, happening just minutes after exposure to an allergen.

If your veterinarian determines your pet is having a mild allergic reaction upon examination, they are likely to recommend an antihistamine, such as diphenhydramine (Benadryl®) for treatment. Do not attempt to treat your pet with an antihistamine without talking to your veterinarian first! The amount of medication a dog or cat takes is much different than what a person needs; your veterinarian will prescribe a proper dosage.

If your pet is having a severe allergic reaction and anaphylaxis is a concern, your veterinarian will initiate immediate treatment to control the allergic response. Treatment in this situation is critical and can include drugs, such as epinephrine, and steroids. Most likely, your pet will be hospitalized and will receive oxygen therapy and, sometimes, fluids, as well. The good news is that when caught in time, your dear friend should return to normal health!

If you have any questions or concerns, you should always visit or call your veterinarian – they are your best resource to ensure the health and well-being of your pets.

Reviewed on: 
Tuesday, July 8, 2014