Even when we make sure to provide our cat with the most nutritious diet, the food Kitty ingests may not always agree with him or her. Substances in the food can trigger an allergic reaction, resulting in gastrointestinal or skin problems which can be difficult to diagnose. Here's what cat owners need to know about food allergies in cats and what to do if you suspect Kitty might have one.
Fact #1 - An allergy is the body's immune reaction to something in the food.
The feline body - much like ours - has an excellent immune system. It identifies hostile bacteria, viruses, as well as toxins and fights them. The immune system's weapon of choice is an inflammation of certain tissues: a small and temporary price to pay when the body is under attack.
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Unfortunately, an overzealous immune system can get confused and mark an innocent chicken or beef protein as the enemy. The resulting inflammation can cause various types of symptoms (we'll soon discuss those) and is generally referred to as an allergy. The protein that causes the reaction is called the allergen.
Fact #2 - Beef, fish, and chicken are common allergens in cat food
It can be difficult to tell which exact protein in a cat's food is the allergen. That's why veterinarians are more likely to address food sources— an animal or plants—as potential allergens. A recent study indicates that the most common food allergens in cats are beef, fish, and chicken.
Fact #3 - Food intolerance is not an allergy
When a cat's lack of ability to digest a type of food causes an upset stomach, we call that food intolerance. It's not an allergic reaction because it does not involve the immune system.
The most common example of food intolerance in cats (and many humans) is that of milk. Milk contains a type of sugar called lactose.
Adult cats can't process lactose very well, so ingesting milk is likely to give them an upset stomach and diarrhea. This is not a food allergy though. The body doesn't identify lactose as a hostile agent - it just can't digest it. More on lactose intolerance in the FAQ section below.
Fact #4 - Food allergies in cats can cause gastrointestinal symptoms
Food allergies in cats often cause chronic vomiting and sometimes diarrhea as well. Of course, not every case of vomiting or diarrhea indicates a food allergy, but once other causes are ruled out, an allergy is often the diagnosis.
Fact #5 - Food allergies in cats can also cause skin problems
It may surprise you to learn that many times food allergies are manifested in the cat's skin, not the stomach. Veterinarians call these CAFR, an acronym which stands for Cutaneous (skin) Adverse Food Reactions.
Symptoms of CAFR can include itching, general inflammation of the skin, and small fluid-filled lumps on a cat’s skin. The cat scratches the itchy areas, which often creates lesions and infections. These skin symptoms are often seen around the cat's head, neck, and chest.
According to a recent study, in 3-6% of cats with skin problems, a food allergy is to blame. Another study found that prevalence was 6% of cases that presented skin inflammation and 10% skin hypersensitivities among cats referred to a veterinary hospital.
Fact #6 - A food allergy can take time to develop
A food allergy doesn't happen overnight. No one knows exactly why an allergy develops, but we do know that in some cases symptoms progress slowly over months and sometimes years. Just because your cat has been eating the same cat food for years with no issues does not mean he or she hasn't developed an allergy to it more recently.
Fact #7 - The best way to diagnose a food allergy is through an elimination diet
While there are some blood and saliva tests that can be done, the only way to confirm a food allergy is by eliminating potential allergens from the cat's diet.
Your veterinarian will probably suggest a diet based on one or two ingredients for a period of several weeks to see if symptoms improve. If they don't, you'll have to try a different limited-ingredient diet to see if that helps. Once you find the culprit, your vet may suggest reintroducing it temporarily to see if symptoms return. If that happens - you know what type of food your cat must avoid from now on.
Fact #8 - Prescription food containing hydrolyzed proteins can help diagnose (and treat) food allergies
Your veterinarian may suggest a hydrolyzed protein diet as a form of elimination diet. Don't let the big name scare you. What this means is simply that the proteins in these formulas are broken down into smaller molecules. These smaller molecules are far less likely to trigger an allergic reaction.
Fact #9 - Limited-ingredient cat foods are not necessarily hypoallergenic
With some cats, all it takes is a microscopic amount of the allergen to trigger a reaction. Eliminating every trace of the offending food can prove to be a challenge with some types of commercial cat food.
Unfortunately, store-bought limited ingredient foods are usually not "pure" enough for an allergic cat. Pet nutritionist Dr. Martha Cline, DVM, explains that the same production lines are often used to create various cat foods. For example, a batch of limited-ingredient chicken-based cat food could be contaminated with traces of beef used to make an earlier batch of cat food in the same production line.
Dr. Cline recommends using veterinary-approved hypoallergenic foods during food trials. Homemade foods are also an option, as long as owners take care to avoid cross-contamination with other types of food. A consult with a board-certified veterinary nutritionist is recommended for cat owners preparing food at home.
Fact #10 - The symptoms of a food allergy don't disappear overnight
Just like it can take time for the symptoms of an allergy to build up, it can also take a while for them to go away. Most affected cats will show improvement within a few weeks once the allergen is removed, with some taking up to 12 weeks. According to this study, 90% of cats will show signs of improvement within 8 weeks.
Fact #11 - Elimination diets must be followed to the letter
A cat can be allergic to more than one type of food, so limited-ingredient hypoallergenic food diets must be followed quite strictly. Owners must watch out for the allergen - or traces of it - in every food or treat they give their cat.
Talk to your vet if you suspect your cat has a food allergy
If your cat suffers from chronic vomiting or skin problems - especially around the head and neck - talk to your vet about food allergies.
Don't try to diagnose food allergies on your own. Vomiting and skin issues can be caused by a multitude of other conditions and diseases. More urgent medical problems must be ruled out before addressing food allergies, so if your cat is showing any of these symptoms, talk to your vet and do not delay professional medical care.
The Cat Food Allergies FAQ
Over the years we have had many questions from our members and visitors. We've put together a short and concise FAQ with some of the more common ones.
Can cats be allergic to cat food?
Absolutely. Cats can be allergic to cat food of any type. The allergic reaction can be to a single substance in the food or to several ingredients. Any protein can be the cause of the allergy, including the most natural of ingredients. That's why a cat can be allergic to dry cat food, wet/canned cat food, commercial raw cat food, and even a 100% homemade diet.
There is nothing wrong with the protein that creates allergic reactions. It can be something like turkey, chicken or fish which would be perfectly healthy for a cat without the allergy (as part of a complete and balanced diet).
Can my cat be allergic to turkey?
Yes. Many cats develop an allergy to turkey protein. They will show symptoms of allergy whenever fed a formula that's either turkey-based or uses turkey in the recipe. It doesn't matter if the formula uses whole turkey, turkey meal, or turkey by-products. Each of these ingredients can trigger an allergic reaction in a cat that's allergic to turkey.
Can my cat be allergic to chicken?
Just like with turkey, or any other protein, a cat can become allergic to chicken. Again, it doesn't matter in which form chicken is included in the cat's diet. Whether as an ingredient in a commercial formula or as a whole home-cooked chicken breast.
Can a cat be allergic to organic cat food?
Organic food can mean all sorts of things. Usually, it means only organic pesticides were used to grow the crops that are in the food. It could also mean the chickens and other farm animals used in the recipe had a diet of organic feed. They may also not have been given antibiotics.
Yes if your cat is allergic to chicken, it's unlikely that an organically grown chicken won't trigger a reaction. After all, the protein is still the same. So yes, cats can be allergic to organic cat food.
Are all cats allergic to cow milk?
Some cats can be allergic to proteins in cow milk but that's actually a rare condition. That said, adult cats are usually lactose-intolerant. While lactose intolerance is a food-related condition it's not an allergy per se.
So, what does it mean to be lactose-intolerant and why is that not an allergic reaction?
Lactose is a form of sugar that's found in milk. The body - feline or human - uses a special enzyme called "lactase" to break down this type of sugar and use it as a nutrient. That's how calves, babies, and kittens are able to digest their mother's milk.
Once they start eating solid foods, cats gradually lose their ability to produce enough lactase to process the lactose in milk. When that happens, we consider that cat to be lactose-intolerant. The exact same thing happens with most humans to some degree or another.
While milk still tastes good to adult cats, if you give them too much of the white stuff, they will experience an upset tummy and probably diarrhea too. That's because the gut bacteria are having a field day, eating up all of that excess lactose that the body can't use. The bacteria multiply and generate gas and that's what causes the symptoms.
So why is that not an allergic reaction? Because there's no involvement of the cat's immune system. Unlike with an allergy, this isn't the body calling the alarm on some protein. These are just the gut bacteria becoming overactive in the presence of lactose. Painful but relatively harmless.
Can a cat be allergic to the food dish?
Not as such. An allergy is the body's reaction to a biological substance, usually a protein. Plastic, steel, and ceramics are not allergens. Even in the highly unlikely event that a cat was to ingest tiny particles of these materials, there is no risk of allergy.
Having said that, cats can have a reaction to food bowls or dishes. Many cats develop bacterial infections on their chin, where their skin comes in contact with a food bowl. The reason for that is a high bacterial load on the dish. When so many bacteria attach themselves to the feline skin, the immune system fails to push them off effectively and they cause local infections.
The key to preventing feline acne lies in choosing the right type of food dish. Opt for stainless steel or ceramics as the material of choice and not plastic. Why? Because plastic can have microscopic scratches and holes where bacteria can multiply. Even if you clean the dish, it can be very difficult to get rid of them all. The truly smooth surface of glazed ceramics or stainless steel doesn't allow bacteria to take hold.
Clean those dishes frequently and you should have no feline acne trouble. Just know that this was not a cat food allergy—or any type of cat allergy—to begin with.
What is food allergy dermatitis in cats?
Derma means skin in Latin. Dermatitis means an inflammation of the skin. It's a symptom and not a disease in its own right, even though doctors and vets often use the term when offering a diagnosis.
It can be easy for a veterinarian to see that a cat's skin is inflamed. Redness, soreness, scratching, and scabs are usually easy to notice. They're the telltale signs of dermatitis—an inflammation of the cat's skin. Dermatitis can be caused by many things but once other potential factors are ruled out, a good allergy is often the main suspect.
Can a food allergy cause scabs?
Yes, but not directly. A food allergy can show up as dermatitis (and we now know what that means!) The inflamed skin feels itchy, making your cat scratch a lot. Sometimes the cat breaks that delicate feline skin while scratching. The tiny wound heals quickly but while this is happening, you'll be seeing a scab.
What's the best dry cat food for allergies? What's the best wet cat food for allergies? Should I start my allergic cat on a homemade diet (raw or cooked)?
We've put these questions together because the answer is the same: Consult with your veterinarian. Don't try to diagnose or treat food allergies on your own.
Whatever you do, be wary of homemade elimination diets. Yes, they can be used but you must do so under veterinary guidance and monitoring. It's easy to get to the point of dangerous nutritional deficiencies with a homemade elimination diet. Your vet should be able to work with you to avoid that situation.
Has your cat been diagnosed with food allergies? Share your story in the comments below or start a thread in the cat health forum to share what you have learned during your battle with this frustrating condition.