Just like us, our furry feline companions can be upset by certain, and specific foods, causing cat food allergy symptoms. Unlike us, it’s more difficult for our kitty to communicate. So, it’s important to be aware of alert factors to quickly identify a cat with food allergy symptoms. 

Studies have shown that food allergies overall are the third most common type of feline allergy, behind allergies to flea bites and inhaled substances. Although skin problems are the most common cat food allergy symptoms, an estimated 10 percent to 15 percent of cats experiencing an allergy or intolerance also exhibit gastrointestinal signs.

We’ll provide an overview of the symptoms to watch for, common ways to identify the ingredient your cat is allergic or intolerant to, and a guide to selecting a feeding plan that will support your cat’s digestive, and overall, health.

Understanding the difference between cat food allergy symptoms, and symptoms of a cat food intolerance

There are two classes of adverse reactions to food: 

• Cat food allergies are those in which an immune response is involved (think immune responses such as swelling, the difficulty of breathing, etc.).
• Cat food intolerances occur without an immune reaction, but can be equally uncomfortable for your cat–these cover a large category range and are typically expressed as digestive symptoms

“In essence, the immune system misidentifies a protein as a foreign invader, like a germ, and attempts to fight it off,” explains Jennifer Coates, DVM, a veterinarian and author based in Fort Collins, Colorado, who serves on the Pet Life Today advisory board explains. “Certain types of white blood cells, called plasma cells, produce IgE antibodies, which, in turn, attach to mast cells that then release histamine and other substances that result in an allergic reaction.”

Excessive itching is the most common, telltale cat food allergy symptom

Adverse food reaction (intolerance) symptoms in cats often mimic cat food allergy symptoms. One differentiating characteristic of cat food intolerance is that the symptoms occur on initial exposure to a food (or food additive). In comparison, cat food allergy symptoms (from an immune-response) usually are seen following several exposures.

Which cat food allergy symptoms should I look for

There are several general categories of cat food reactions that may occur:

• Food Poisoning– an adverse reaction caused by the direct action of a food that may include the following:
• Excessive amounts of a specific nutrient like vitamin A or vitamin D– 
• Scavenging of spoiled food– dumpster divers and shameless hunters beware!
• Ingestion of plants known to cause gastrointestinal irritation (rhubarb, pothos, )
• Food additives– sulfites, monosodium glutamate, certain spices, disulfide (found in onions that can cause damage to red blood cells)

• Drug-like reactions to food. Histamine, which can sometimes cause severe clinical reactions in humans (flushing, diarrhea, sweating, nausea, vomiting, and facial swelling) may not be an issue in cats except for the occasional idiosyncratic reaction.
• Carbohydrates. Carbohydrate intolerance in cats is less frequent than in humans. However, one that’s fairly common for cats is lactose intolerance–diarrhea, vomiting, bloating, and abdominal discomfort after consuming milk
• Dietary indiscretion (i.e. kitty is eating something they shouldn’t be)–GI signs may be caused by bacterial contamination, fat or grease, or from bones.

Unhappy kitty? Make sure you rule out cat food allergy and intolerance symptoms.

True cat food allergy symptoms, symptoms of a true immune response, often show the following:

• Chronic, year-round itching and skin inflammation typically affecting the face, ears, belly, groin, armpits, and the legs/paws – watch out for your cat over-grooming (hair loss, abrasions, scabs etc)

“A key clue that it might be an allergic reaction to a specific food and not simply a food intolerance is to take note if your cat is starting to itch and scratch a lot. A cat with food allergies may develop scabs from the scratching, loss of fur from constant licking and even have red bumps on his face, ears and abdomen,” says Dr. Elisa Katz, DVM, a veterinarian based in the Chicagoland area who serves on the Feline Nutrition Foundation board.

“The itching eruptions primarily affect the head and neck area,” says Carolyn McDaniel, VMD, a lecturer in clinical sciences at Cornell University’s College of Veterinary Medicine. “They’re not always in that area, but often enough to serve as a clue that the source is a food allergy.”

• Recurrent infections of both the skin and ears (sometimes the only clinical cat food allergy symptom experienced).
• Gastrointestinal signs, such as vomiting or diarrhea.
• Itching around the rectum, which leads to scooting (ugh, uncomfortable for our kitties and bad for our floors!).
• Frequent bowel movements, or strain when they are using the litter box.
• Food avoidance resulting in weight loss.
• Be careful of this one: Some cats can be severely allergic to shellfish, severe allergy indicators can include anaphylaxis or shock, plummeting the blood pressure, causing difficulty breathing, loss of bladder/bowel control and even collapsing into unconsciousness. This is an emergency requiring immediate veterinary care.

Food sensitivities or intolerances differ from true cat food allergies in that they don’t evoke an immune response. A cat food intolerance is a gradual reaction to a certain ingredient in your cat’s food that doesn’t agree with their system, although not life-threatening, intolerances can be very uncomfortable for your furry companion! Look out for these digestive symptoms:

• Gas
• Diarrhea
• Abdominal cramps and bloating (since kitty can’t tell you these are happening, watch for general signs of stomach discomfort like rolling around, biting or scratching at the belly)
• Food avoidance resulting in weight loss

The most common cat food allergens

The most common cat food ingredients associated with food allergies (and intolerances) in cats include protein sources: beef, fish, chicken, and dairy products. Please note: only limited research has been conducted at this time, and there may be other common allergens that we have not yet identified.

These human foods are harmful to cats and should be avoided:

• Alcohol
• Chocolate
• Tea, coffee and energy drinks
• Cheese and milk
• Fat trimmings
• Raw eggs, raw meat and raw fish
• Grapes and raisins
• Onions and garlic
• Avocado
• Harmful bones
• Xylitol

I think my cat has an allergy or intolerance, now what can I do?

If you think your cat may be allergic or sensitive to its food, an elimination trial is used to clear the reaction and determine the cause.

Here's the process:

1. The elimination diet challenge (12 weeks recommended)
2. Reintroduce foods to identify offenders 

Step 1: The cat food allergy elimination trial

According to veterinary advice, the most accurate method of diagnosing a cat food allergy is to remove all potential allergens over the course of 12 weeks. This is called an elimination trial. 

This new elimination diet must not contain any ingredients that the pet has eaten in the past (as anything eaten in the past can be a potential trigger). During the trial, all other foods and supplements need to be avoided. Yes, this includes treats, vitamins and preventatives like heartworm supplements. However, it’s suggested the new diet should be introduced gradually over a 5- to 7-day period as some animals may develop GI problems if their diet is changed too abruptly.

Here's a helpful brochure on elimination trial recommendations >

Important considerations for elimination diets to alleviate cat food allergy symptoms:

• An elimination diet is not just changing from one brand of pet food to another – ”allergy” or limited ingredient” pet foods available can still contain additives, ingredients, and preservatives not listed.
• Home-cooked diets are a great solution, but also contain important considerations to ensure the diet is nutritionally balanced and avoiding all potential allergy symptom triggers (we included more detail below).
• Therapeutic diets. Veterinary dermatologists often prescribe therapeutic diets from Royal Canin, Hill's, and Purina for use in elimination trials. In addition, Rayne Clinical Nutrition makes rabbit, kangaroo, and pork diets for dogs and cats that are less processed than dry kibble or canned foods. Selecting a diet will depend on your patient's diet history. Furthermore, some cats and dogs will require a wet food to help administer medications, and some owners are adamant about having treats to feed their pet. Knowing the needs of your patient and client will help in choosing the most appropriate diet for your patient.
• Absolutely no other food products or treats should be given during an elimination diet trial is imperative. The pet should be allowed to consume only the prescribed diet, associated treats, and water (no table food, no rawhides, no supplements, no parasite preventatives, toothpaste or meds with added flavor, no treats used to administer meds)

Step 2: Reintroduction following the elimination trial

To find the best cat food for cats with allergies, the next step is to reintroduce. Once your cat’s food allergy symptoms are reduced or eliminated at the 12-week mark, it’s the right time to get started.

The purpose of this is to identify which ingredient causes the reaction, so you can carefully avoid within your cat’s diet moving forward.

Here’s how you do it:

• Slowly reintroduce 1 food at a time, we’d recommend one every 3 days as cat food allergy symptoms (and symptoms of intolerance) are not always immediately following consumption
• Carefully watch your cat for symptoms
• When you notice a trigger, note the food as a don’t feed!
• Be aware that cats can be allergic or sensitive to more than one ingredient, so to fully complete the reintroduction phase, each food should be reintroduced

Talk to your vet about cat food allergy tests

This is where working with your vet comes back around as being really important. If the cat food allergy symptoms are moderate to severe, blood tests may give an indication of food allergies, on a shorter timeline. These ‘serum IgE tests’ are a cat food allergy test option to discuss with your vet.

Kick the preservatives and switch to a (real!) natural hypoallergenic food diet, free from preservatives and additives

What’s a fail-safe method of a hypoallergenic diet? Feeding your cat something where you know exactly what’s inside. 

Fresh, natural cat food is hypoallergenic–perfect for elimination diets and ongoing nutrition!

Eliminate cat food allergies along with the symptoms and risks that come with them by feeding your feline the best food for cats with allergies. Feeding fresh ensures you have complete control over the quality of the ingredients, and which ingredients are used. Fresh, gently-cooked cat food makes for a perfect hypoallergenic cat food diet.

Important considerations for hypoallergenic elimination (and ongoing) cat diets:

• It must consist of nutritionally balanced – it’s recommended to consult with a board-certified nutritionist before feeding any homecooked cat food diet
• Food safety is equally important for our pets as it is for us, it’s critical that safe food handling, preparation, and storage processes are followed
• Websites including balanceit.com and raynenutrition.com have also been helpful in formulating home-cooked diets for a trial

Learn more the benefits of feeding your cat fresh, naturally hypoallergenic cat food

Transitioning to natural hypoallergenic cat food can be another time-consuming part of your routine, and often a stretch to add into most people’s lifestyle.

Homecooked, natural, hypoallergenic cat food is simple with Kafka’s Organic.

At Kafka’s Organic, we’re dedicated to making fresh, healthy, hypoallergenic cat food accessible. Our fresh, hypoallergenic cat food recipes are made with real food that’s ALWAYS free of preservatives and additives. You can even calculate exactly how much fresh cat food your feline should have with our cat food calorie calculator.

Shop the best fresh hypoallergenic cat food, perfect for cats with allergies and sensitivities.