Common allergens affecting domestic cats and feline atopy (infographic)

Allergens affecting cats and feline atopy
Allergens affecting cats and feline atopy. Infographic by MikeB
Two useful tags. Click either to see the articles:- Toxic to cats | Dangers to cats

Cats can be allergic to a variety of substances, but the most common allergens affecting domestic cats include:

  • Food allergens: Some cats can develop an allergy to certain ingredients in their diet, such as chicken, beef, fish, dairy, or grains.
  • Environmental allergens: Cats can also be allergic to environmental factors such as dust mites, mold, pollen, and second-hand smoke.
  • Flea bites: Flea bites can cause an allergic reaction in some cats, leading to itching, biting, and hair loss.
  • Fabrics and materials: Some cats can develop an allergy to certain fabrics or materials, such as wool, carpet, or plastic.

If you suspect that your cat has an allergy, it’s important to consult with a veterinarian for proper diagnosis and treatment. It is often a tricky diagnosis

What is an allergen?

An allergen is a substance that can cause an allergic reaction. In some cats, other animals and people, the immune system recognizes allergens as foreign or dangerous. As a result, the immune system reacts by making a type of antibody called IgE to defend against the allergen. This reaction leads to allergy symptoms.

Overlap with people

There is an overlap in the allergens that affect domestic cats and people, often their caregiver. For example, mold spores affect people as well as pollen and dust mites. Other allergens affecting people might be fabrics and ironically cat dander containing the Fel D1 allergen, horsehair, houseplants, stuffed toys, bedding and some cleaners.

Feline atopy

Cat atopy is a hypersensitivity reaction caused by the immune system perceiving allergens as a threat causing the system to produce immunoglobulin E antibodies which are specific to a particular environmental allergen otherwise known as antigen.

The allergic reaction described by feline atopy is one which is not caused by a flea bite allergy or a food allergy. It is, as mentioned, reaction to environmental allergens.

To put this another way: inside the home of a domestic cat there might be small particles called allergens in the air and the cat’s immune system thinks these are a threat to the health of the cat and it attacks them by producing antibodies in the skin or that are circulating around the body. This reaction can cause atopic dermatitis. This is a skin rash which is very itchy and it won’t go away. This is also called pruritic skin disease or pruritic dermatitis.

How common?

Importantly, science has concluded from information gathered over 11 years (2001 to 2012) that the disease affects 12.5% of domestic cats in the USA. VCA Animal Hospitals say:

“Approximately 10-15% of cats treated by veterinary dermatologists are diagnosed with atopy.”

As pruritic skin disease (pruritus) is very itchy the cat tends to constantly groom the area which effectively barbers their coat down to the skin. They become bald where they are grooming.

Sometimes seasonal

The problem may be seasonal because some of the allergens are present at certain times of the year such as pollen which gets into the home. Or it will affect cats allowed outside.


Feline atopy can be a difficult to diagnose disease because of the range of possibilities and therefore a clear picture of what is going on may be difficult to see.

The condition is serious. You will see some pretty horrible pictures on the Internet of domestic cats with skin which is in a very bad state and large areas of hairlessness and visible signs of dermatitis. Sometimes only the ear flaps are involved and they are very upsetting for the cat. They scratch and damage their ears. There is a moist discharge.

A veterinarian will diagnose based upon the health history of the patient, clinical symptoms and by excluding other possible diagnoses.

Below are some articles on allergies.

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