Cat Food Allergies: Allergens, Symptoms, and Treatment

Food allergies are about as common with cats as they are with any other creature, including humans. Diagnosing food allergies can be a tricky business, however, as every cat’s allergic reaction can differ from the next. You may have already tried several approaches as easing your cat’s symptoms before coming here, or this may be your first port of call. Either way, we hope that the information provided below will help you to figure out what’s causing your beloved pet’s cat food allergy and what you could do to help ease their discomfort – or remove the problem altogether.

What are Food Allergies in Cats?

Multiple studies into cat allergies have managed to deduce that food allergies are the third most common allergy type found in felines (topped only by inhalant allergies and flea saliva). Food allergies are caused by your cat’s immune system misidentifying one or more of the proteins in a particular food. This misinterpretation leads the body to believe that the protein is invading the body as opposed to feeding it, resulting in immune response (or allergic response) to counteract it.

According to Carolyn McDaniel, VMD, who lectures in clinical sciences at Cornell University’s College of Veterinary Medicine, cats can develop food allergies at any age. Food allergies can also affect cats whose diets have not changed since adolescence, or for many years.

Food allergies are not to be confused with food intolerance. Allergic reactions can be treated short-term with antihistamines if required, whereas intolerances cannot. Though preferably the offending food should be avoided with both conditions.

What are the Signs of Cat Food Allergies?

Cat food allergies can be indicated by a variety of symptoms that can either impact the cat individually or several at a time. Pet food allergy symptoms include:

• Skin Inflammation: The most common allergic reaction with food allergies is skin inflammation. Inflammed skin is extremely unpleasant for the cat as it causes severe irritation and a constant itching sensation. Cat skin problems are prevalent with many allergy types, hence the difficulty in diagnosing food allergies, to begin with.
• Persistent Scratching: The irritation caused by their inflamed skin can lead to a cat scratching at itself constantly to try and alleviate the symptoms. Unfortunately, this can cause them to break the skin leaving lesions in the skin.
• Hair Loss & Coat Deterioration: This is also a result of inflamed skin. Hair loss can be caused by the cat constantly scratching in localized areas (often the head and neck), or by an overall loss of functionality in the hair follicles as a result of skin damage.
• Digestive Upset & Vomiting: Gastrointestinal problems are one of the easier-to-spot symptoms of a food allergy, especially with indoor cats. This is because cat owners with indoor cats will be able to easily monitor their cat’s bowel movements via the litter box. Outdoor cats may be more difficult to monitor unless they have an accident in the house.
• Recurrent Ear Infections: Ear infections are another knock-on symptom caused by skin irritation and inflammation. It is also prompted by a weakened immune system. The typical symptoms include your cat scratching at its ear or shaking its head, a bad smell coming from the ear, discharge around the ear cavity, or head tilting.
• Foot Licking: Foot licking is a soothing gesture that both cats and dogs do in an attempt to relieve some of their discomfort or anxiety. Though constant foot licking can lead to your cat swallowing fur which could lead to fur balls or further digestive distress. Therefore we could recommend using an anti-furball treatment if foot licking is a constant issue.
• Irritability: If your cat is not usually the irritable type, then it could be as a result of the above symptoms having an impact on their mental health. This can be among the more unusual symptoms, as most cats don’t let their discomfort outwardly show. Therefore if your cat is becoming irritable it is likely that their allergy is taking its toll, signifying the possibility of it being a long-term problem that has perhaps flown under the radar.
• Avoiding Contact: If your cat is feeling sensitive or possibly in pain, they may become aloof in an attempt to avoid direct contact. Many affected cats take this approach, as it’s not within a cat’s nature to show when it is feeling vulnerable. Alternatively, your petting may be uncomfortable on its delicate skin.

How to Diagnose and Treat a Cat Food Allergy

Proper diagnosis of a cat food allergy will entail getting your vet involved. Most food allergies occur within 2 years of a cat being weaned. However, as previously mentioned, food allergies in cats can be caused either by exposure to a new food that their body does not agree with, or overexposure to a food that the body has developed an allergy for, even with the most nutritionally balanced diet.

Rather frustratingly, a cat allergy can be extremely difficult to diagnose. Most vets test for other, more easily diagnosed problems, before resorting to food allergies. Initial tests may include testing for flea dermatitis, monitoring the cat’s allergies over a year to check whether they are seasonal, before moving on to the provocation food trial.

In order to get allergic cats back to their happy and healthy selves, it takes a lot of time and patience when it comes to food allergies. Even the allergy-specific tests that claim to be able to accurately diagnose food allergies in cats have not been definitively proven, with some studies showing the test diagnosing allergies to substances such as plain water and faux fur.

What is an Exclusion Diet Trial?

Dietary elimination trials are the only effectively proven ways to sus out what could be triggering a cat’s reactions. Most vets will recommend a restricted diet, made stripping your cat’s diet back to the bare essentials. This restricted diet should contain foods that your cat has never eaten in order to remove the risk of any nasty after-effects. Ordinarily the initial (hopefully) hypoallergenic diet would contain a single protein, a single carbohydrate, and carefully selected fats, vitamins, and minerals – which would all be discussed and decided with your vet.

The Different Trial Types

There are two types of diet trials your vet might recommend to you; a hydrolyzed protein diet (which contains protein that has been broken down to a point where the body no longer recognizes the allergens), or a novel protein diet, in which you will be required to use more unusual proteins such as duck or venison. Each is a bland diet designed to be as gentle as possible on your cat’s body, and hopefully, be allergen-free.

The Initial Trial

The first food trial should be maintained for at least 8 weeks before evaluating the results. During this time it is a good idea to maintain a diary of your cat’s symptoms – when they occur, whether they have lessened or worsened, any new symptoms that arise, any existing symptoms that dissipate. You should always have any new or unusual symptoms checked over with your vet. If your vet suspects that an element of the new recommended diet trial is at fault, they may alter the diet to remove what they think to be the food type responsible for the new symptoms.

Continuation of the Trial

Once you have finished the initial trial, if your cat does not show any allergy symptoms, you can choose to keep them on the hypoallergenic diet you have developed. Alternatively, you could begin reintroducing essential nutritional ingredients back into this recommended diet trial and watch for any skin or gastrointestinal signs that could indicate the allergy returning.

Ordinarily, continuing with the trials would involve slowly reintroducing proteins that most young cats develop allergies to as they get older, starting with the least likely culprit and moving up the list. Once the proteins have been cleared, then you will move on to common carbohydrate allergens that are known for causing food allergies in cats – often only tiny amounts will be added at a time. the food trial will continue, making small adjustments to the recipe as you go, until you find a diet that both you and your cat are happy with.

Diagnosing The Allergy

A dietary elimination trial can take months, if not years to complete. Many owners opt to stick with a simple hypoallergenic recipe and go on without knowing the exact cause of the allergy. Others will continue until the precise allergen has been located. This is up to the individual owner – if you’re happy with the diet you have set out for your cat during your food trial, there’s no real reason to continue unless you want the freedom of being able to give your cat anything now that you know what to look out for.

What are The Most Common Allergens in Cat Food?

Knowing what triggers your cat’s specific problems can really help to eliminate the stress surrounding meal times as well as give your cat a more comfortable life overall. When vets recommend food trials they often aim to avoid the following allergens, just to be on the safe side. They will later reintroduce these allergens one at a time to see which one triggers the reaction. The main known feline allergens are:

• Dairy products (cats can’t properly digest milk once they’re weaned)
• Chicken
• Beef
• Pork
• Fish (not salmon – specifically “fish” as stated on the recipe)
• Egg
• Milk
• Soy
• Corn
• Wheat
• Gluten
• Rice

Conclusion

Cats with allergies to a particular food can struggle more than you might think, with severe skin irritation and lesions becoming a daily companion, taking its toll on their mental state and impairing their ability to function properly. If you worry that your cat might have a food allergy, we recommend diet trials laid out by your veterinarian. Be sure to heed your vet’s advice and stick strictly to the diet laid out if you want your cat’s health to improve. It can be a long road, but so worth it.

FAQs:

Q: How long does it take a cat to recover from a food allergy?

A: It could take anything from weeks to months or even years depending on the success of the limited ingredient food trial laid out by your vet. Most feline owners will see an improvement in skin and gastrointestinal problems within a few weeks owing to the simplicity of the elimination diet – though this could change when new ingredients are introduced.

Q: How can I soothe my cat’s itchy skin?

A: Removing any allergens, be then environmental, inhaled, or food-related is the best way to ditch that itch. But if you’re unsure of the allergen, then for the meantime it is possible to purchase itch-relieving medicated shampoos, sprays, and topical ointments via your vet to help provide temporary relief.

Q: Can cats be allergic to chicken?

A: Yes. It is possible for cats to develop an allergy to chicken over time. There are also several other protein sources that are common allergens, including pork, beef, and egg. If this is the case then it is best to switch to “novel” proteins such as venison, duck, or rabbit.

Q: Can cats be allergic to rice?

A: Yes, though rice is a less common allergy, it is still an allergen nonetheless. Unfortunately, it can be difficult to find cat foods without rice in, though there are several cat food brands that offer limited ingredient diet-friendly foods.

Q: What protein is best for cats with allergies?

A: “Novel” proteins, otherwise known as protein sources you don’t ordinarily get in cat food, are your best option for cats with protein-related allergies. These include kangaroo, venison, rabbit, and duck, though there are many more protein options available in the “novel” category.

Q: Are food allergies the same as food intolerances?

A: No. Food allergies require a response from the immune system in order to be considered as such (as is made clear by the definition of food allergies which states them to be “all immune-mediated reactions”). Food intolerance does not require an immune response and is often restricted to gastrointestinal distress without impacting other organs.

Sources:

1. Food Allergies, Cornell University College of Veterinary Medicine
2. What every pet owner should know about food allergies, Clinical Nutrition Service
3. The Itchy Pet – Food Allergies in Dogs and Cats, MSPCA-Angell
4. Food allergy in the cat: a diagnosis by elimination, PubMed