Even when we make sure to feed our cat the most nutritious diet, the food she eats may not always agree with her. Substances in food can trigger an allergic reaction, resulting in gastrointestinal or skin problems that can be difficult to diagnose. Here’s what cat owners need to know about cat food allergies and what to do if you suspect kitty might have one.
fact #1 – an allergy is the body’s immune reaction to something in food.
The feline body, like ours, has an excellent immune system. identifies hostile bacteria, viruses and toxins and fights them. the preferred weapon of the immune system is 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 discuss them soon) and is generally known as an allergy. the protein that causes the reaction is called an 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 inability to digest a type of food causes an upset stomach, we call it a food intolerance. it is 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 milk. milk contains a type of sugar called lactose.
Adult cats can’t process lactose very well, so ingesting milk is likely to cause stomach upset and diarrhea. however, this is not a food allergy. the body does not identify lactose as a hostile agent, it simply cannot digest it. more about 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 all cases of vomiting or diarrhea indicate a food allergy, but once other causes are ruled out, the diagnosis is usually an allergy.
Fact #5: Food Allergies in Cats Can Cause Skin Problems Too
It may surprise you to learn that food allergies often show up on the cat’s skin, not the stomach. veterinarians call them cafr, an acronym that stands for Cutaneous (Skin) Adverse Food Reactions.
Symptoms of cafr can include itching, general inflammation of the skin, and small fluid-filled bumps 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 the prevalence to be 6% of cases of skin inflammation and 10% of skin hypersensitivity 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 slowly progress over months and sometimes years. Just because your cat has been eating the same cat food for years without problems doesn’t mean he hasn’t developed an allergy to it more recently.
fact #7 – the best way to diagnose a food allergy is through an elimination diet
Although some blood and saliva tests can be done, the only way to confirm a food allergy is to eliminate possible allergens from the cat’s diet.
Your vet will likely suggest a one or two ingredient diet over 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 kind of food your cat should avoid from now on.
Fact #8: Prescription foods containing hydrolyzed proteins can help diagnose (and treat) food allergies
Your vet may suggest a hydrolyzed protein diet as a form of elimination diet. don’t let the big name scare you off. what this means is simply that the proteins in these formulas are broken down into smaller molecules. these smaller molecules are much 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. removing all traces of the harmful food can be challenging with some types of commercial cat food.
Unfortunately, limited-ingredient store-bought foods are generally 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 trace amounts of beef used to make a previous batch of cat food on the same production line.
dr. cline recommends using vet-approved hypoallergenic food during food testing. Home-cooked foods are also an option, as long as owners are careful to avoid cross-contamination with other types of food. Consultation with a board-certified veterinary nutritionist is recommended for cat owners who prepare food at home.
fact #10 – food allergy symptoms don’t go away overnight
Just as allergy symptoms can take time to develop, they can take time to go away. most affected cats will show improvement within a few weeks once the allergen is cleared, 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 should be followed to the letter
A cat can be allergic to more than one type of food, so limited ingredient hypoallergenic food diets should be strictly followed. owners should watch for the allergen, or traces of it, at every meal 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 problems can be caused by a multitude of other conditions and diseases. more pressing medical issues need to be ruled out before addressing food allergies, so if your cat exhibits any of these symptoms, speak to your vet and don’t delay professional medical attention.
Frequently Asked Questions About Cat Food Allergies
Over the years, we have received many questions from our members and visitors. we’ve put together a short and concise FAQ with some of the most common ones.
can cats be allergic to cat food?
absolutely. cats can be allergic to cat food of any kind. the allergic reaction may be to a single substance in the food or to several ingredients. Any protein can be the cause of the allergy, even the most natural 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’s nothing wrong with protein that creates allergic reactions. it could be something like turkey, chicken or fish that would be perfectly healthy for a cat without an allergy (as part of a complete and balanced diet).
Could my cat be allergic to turkey?
yes. many cats develop an allergy to turkey protein. they will show allergy symptoms as long as they are given a turkey-based formula or turkey is used 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 allergic to turkey.
Can my cat be allergic to chicken?
Just like turkey or any other protein, a cat can become allergic to chicken. again, it does not matter in what form chicken is included in the cat’s diet. either as an ingredient in a commercial formula or as a whole homemade chicken breast.
can a cat be allergic to organic cat food?
organic food can mean all sorts of things. it usually means that only organic pesticides were used to grow the crops found in food. it could also mean that the chickens and other farm animals used in the recipe had a diet of organic foods. they may not have received antibiotics either.
yes, if your cat is allergic to chicken, an organically grown chicken is unlikely to cause a reaction. after all, the protein remains the same. so yes, cats can be allergic to organic cat food.
Are all cats allergic to cow’s milk?
Some cats may be allergic to cow’s milk proteins, but it’s actually a rare condition. That being said, adult cats are often lactose intolerant. while lactose intolerance is a food-related condition, it is not an allergy per se.
So what does it mean to be lactose intolerant and why isn’t it an allergic reaction?
Lactose is a form of sugar 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. this is how calves, babies and kittens can digest their mother’s milk.
once they start eating solid food, 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. exactly the same is true of most humans to one degree or another.
Although the milk still tastes good to adult cats, if you give them too much white stuff, they’ll experience an upset stomach and probably diarrhea as well. that’s because gut bacteria are having a field day, consuming all that excess lactose that the body can’t use. the bacteria multiply and generate gas and that is what causes the symptoms.
so why isn’t it an allergic reaction? because there is no involvement of the cat’s immune system. unlike an allergy, this is not the body raising the alarm about some protein. these are just the gut bacteria that become overactive in the presence of lactose. painful but relatively harmless.
can a cat be allergic to food bowl?
not as such. an allergy is the body’s reaction to a biological substance, usually a protein. plastic, steel and ceramic are not allergens. even in the very unlikely event that a cat ingests minute particles of these materials, there is no risk of allergy.
That being said, cats can have a reaction to bowls or plates of food. many cats develop bacterial infections on their chins, where their skin comes into contact with a food dish. the reason for this is a high bacterial load in the dish. when so many bacteria adhere to the skin of cats, the immune system cannot expel them effectively and cause local infections.
The key to preventing feline acne is choosing the right type of food dish. opt for stainless steel or ceramic 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 plate, it can be very difficult to get rid of all of them. the truly smooth surface of glazed ceramic or stainless steel does not allow bacteria to take hold.
Clean those dishes often and you shouldn’t have feline acne problems. Just know that this wasn’t a cat food allergy to begin with, or an allergy to cats of any kind.
what is food allergy dermatitis in cats?
derma means skin in Latin. dermatitis means an inflammation of the skin. it is a symptom and not a disease in its own right, although doctors and veterinarians often use the term when offering a diagnosis.
It can be easy for a vet to see that a cat’s skin is inflamed. redness, pain, scratching, and scabbing are usually easy to notice. are 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 prime suspect.
can a food allergy cause scabs?
yes, but not directly. a food allergy can manifest as dermatitis (and now we know what that means!), inflamed skin feels itchy, causing your cat to scratch a lot. sometimes the cat breaks that delicate feline skin by scratching. the small wound heals quickly, but while this is happening, you will see a scab.
what is the best dry cat food for allergies? what is the best wet cat food for allergies? Should I start a homemade diet (raw or cooked) for my allergic cat?
We’ve put these questions together because the answer is the same: see your vet. do not try to diagnose or treat food allergies on your own.
whatever you do, be careful with homemade elimination diets. yes, they can be used, but you must do so under veterinary supervision and supervision. it’s easy to reach the point of dangerous nutritional deficiencies on 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 on the feline health forum to share what you’ve learned during your battle with this frustrating condition.
