Some cats may have allergies to certain foods. This can cause skin itchiness, vomiting, or diarrhea. Today, our Rochester veterinarians will discuss food allergies in cats, the symptoms, and what you can do to help.

What is a food allergy?

A food allergy is a negative reaction that occurs when a cat's immune system reacts excessively to a previously exposed food substance. A cat with a food allergy to a specific ingredient must have eaten that ingredient before. Food allergies primarily affect the skin, but they can also cause gastrointestinal distress, including diarrhea and/or vomiting.

You will be relieved to learn that food allergies are uncommon in cats, affecting only about 1% of all cats. There is no evidence of an association between age, gender, or breed.

What foods are typically associated with a food allergy?

Cats frequently develop food allergies to beef, fish, chicken, and dairy. A cat's allergy must have been triggered by exposure to a food ingredient. You should be aware that even if a cat has consumed an ingredient for a long time, it may still develop an allergy later in life. There has been little research in this area, and it is possible that additional allergens have not yet been identified.

What are the symptoms of a food allergy?

Itching is the most common symptom of a food allergy. The itching can happen anywhere, but the most likely spots are the head and neck.

Other symptoms may include:

  • Licking
  • Scratching
  • Overgrooming
  • Biting

Because of the constant itching, skin lesions may also appear. These can include:

  • Small crusts (miliary dermatitis)
  • Redness
  • Papules
  • Self-induced trauma (sores due to biting, scratching, or licking)
  • Self-induced hair loss (due to biting, scratching, or licking)
  • Ulcerations
  • Plaques (raised circular nodules)

Less commonly, your cat may also suffer from an upset stomach, which can mean diarrhea, vomiting, or both.

Are there risk factors for food allergies in cats?

Genetics play a role in food allergies, which are often linked to atopy (allergic reactions to inhalants or the environment). Atopy can develop in cats at any age after three months, and both male and female cats are equally susceptible to food allergies.

How can a veterinarian diagnose a food allergy?

An elimination diet trial is the most reliable test for determining food allergies in cats. This test involves feeding a diet devoid of any proteins to which your cat has previously been exposed. This trial is expected to last at least eight weeks. A trial diet could include:

Veterinary hydrolyzed protein diet, in which the protein molecules are broken down to a size too small for your cat's immune system to recognize.

Veterinary novel protein diet that contains no products found in your cat's previous foods.

Home-prepared novel protein diet that contains no ingredients found in your cat's previous diets.

During the elimination diet trial, your cat must only eat the food that your veterinarian has prescribed. During the trial, no additional treats, supplements, or edible products should be administered. The next step is to hold a food challenge to reintroduce the cat's previous food. If the cat's symptoms improve after the diet but return within a week of returning to their regular food, they have a food allergy.

Chronic itching caused by food allergies can also be caused by external parasites, bacterial infection, yeast infection, or other allergies, so additional testing to determine the cause(s) of your cat's skin condition is frequently recommended.

How are food allergies in cats treated?

Food allergies in cats are treated by feeding them an allergen-free diet. Prescription diets are preferred due to their stricter quality control. Over-the-counter cat food may contain contaminated proteins. Retail pet foods may claim to be 'limited-ingredient' or to not contain allergens, but they are not produced under the same health and safety standards as veterinary diets.

Regardless, once you've found a diet that works for your cat, you must stick to it for the long term, avoiding cat treats and other foods containing the allergen. Cats with food allergies have a favorable prognosis with proper dietary management.

Note: The advice provided in this post is intended for informational purposes and does not constitute medical advice regarding pets. For an accurate diagnosis of your pet's condition, please make an appointment with your vet.

Do you believe your cat might be suffering from a food allergy? Contact our Rochester vets today to book an appointment for your feline friend. We may be able to help you find the source of the allergy and refer you to a veterinary dermatologist in the area.