Allergies are a relatively common problem in cats. Whether they are caused by environmental allergens, flea bites or food, the symptoms of allergies can drive your cat crazy—from itchy, inflamed skin to vomiting and diarrhea.

Food allergies are not as common as other types of cat allergies, but they can be frustrating to deal with when they do occur. Cats can develop food allergies to any number of ingredients. The allergies can develop over time, whether you’ve recently switched to a new pet food and your
pet begins reacting, or your pet has been on the same food for years.

Common Allergens Found In Cat Food

Food allergies happen when your cat’s body mistakenly identifies an ingredient as an invader that will do the body harm. Once this happens, an immune system response is triggered each time your cat comes into contact with that allergen, often causing inflammation, gastrointestinal
upset and other symptoms.

Food allergies normally occur when your cat has been exposed to a particular ingredient for a long time. Thus, filler products or common proteins are some of the most likely causes of allergic reactions in cats

• Beef: Beef is a common protein source in many cat foods and is known to trigger allergic reactions in cats with food allergies, likely because of its prevalence.
• Fish: Fish is another extremely common protein in cat food, which means many cats can be susceptible to developing allergies to seafood.
• Milk: Although we often believe cats love milk, dairy products are a common factor in feline food allergies. Cats can develop reactions to the lactose in milk and react negatively to it.
• Corn: Corn is a very common carbohydrate filler product added to a variety of dry cat foods. Because of its prevalence, many cats develop allergies to corn.
• Wheat gluten: Wheat is another common carbohydrate product added to cat food to bulk it up. Like corn, many cats develop allergies to this common filler ingredient.
• Artificial food dyes: Some pet food companies add food coloring to their cat food products to make them look more appetizing (more so for humans than for cats). These dyes are known to trigger allergic reactions in some cats.

Just because an allergen is common among cats does not mean your cat will become allergic to it. Every cat develops allergies differently, and many will not become allergic to food at all.

Identifying and alleviating food allergies

If you notice that your cat is experiencing symptoms of food allergies, such as vomiting and diarrhea, itchiness, hair loss, inflamed skin or coughing and sneezing, you should take it to the vet to have it examined and rule out other, more serious, health problems. If your vet suspects that food allergies are to blame, you’ll need to adjust the cat’s diet to identify the source of the allergy and work to eliminate it from the diet entirely.

This process can be tedious. You’ll first want to switch your cat to a new food that contains an entirely different protein and carbohydrate than it has had in the past. This way, it is unlikely that your cat will react to its new food and can still get its full scope of nutrients. The cat will need to be monitored to ensure that its symptoms clear up.

Then, you can begin food trials to identify the specific cause of the allergy. To do this, you need to re-introduce certain types of foods into your cat’s diet one at a time and continue to monitor it for allergic reactions. Most food allergy reactions occur within three to seven days after eating the food, so you’ll need to take it slow.

This process can take months, since each ingredient needs to be “tested" individually, and requires a lot of patience and strict adherence to the new diet your cat has been placed on. Giving your cat treats or other food containing non-novel ingredients can throw off the food trial and cause confusion over what your pet is truly allergic to.

Once you have identified the allergens, you’ll want to permanently remove them from your cat’s diet, switching to a food that does not contain those ingredients. Allergies often stick around for life, so your cat will need to remain on different food to avoid symptoms.

Picky Cats and Diet Changes

Cats are known to be finnicky eaters, so switching their food and getting them to eat can be a struggle—particularly if the diet continues to change.

To help with this, take all diet changes slow. Avoid switching things over too quickly, both to prevent gastrointestinal upset and to help your cat adjust to the new food. You can also add a little water to the food to improve its consistency or warm it up before serving it to make it more
palatable for your cat.

With a lot of patience and careful observation, you should be able to identify the source of your cat’s food allergies and remove harmful ingredients from its diet to provide it with relief and nutritious meals.