Even though we provide our cats with the most nutritious diets, it is possible that these foods are not suitable for cats. This is because substances in the food can trigger allergic reactions, leading to difficulty diagnosing gastrointestinal or skin problems. Here are 10 truths owners need to know about food allergies in cats.
Fact 1: Allergies are the body’s immune response to a substance in food
The cat’s body, similar to humans, has an excellent immune system. It can recognize bacteria, viruses. The immune system’s weapon of choice is inflammation of specific tissues: when the body is attacked, paying the price of inflammation of certain parts of the body.
Unfortunately, the immune system can sometimes get confused and take some chicken or beef proteins as bacteria or viruses. The resulting inflammation can lead to various symptoms (which we will discuss soon), often called allergies. The protein that causes the reaction is called an allergen.
Fact 2: Beef, lamb, seafood, corn, soy, dairy products, and wheat gluten are common allergens in cats
As you may have noticed, the most common allergens are the most common ingredients in cat and dog foods. For cats, the most common allergens are beef, lamb, seafood, corn, soy, dairy, and wheat gluten. This correlation is not a coincidence. While some proteins may be slightly more antigenic than others, many are similar in form, and the incidence of allergic reactions may be related to the amount of exposure.
Fact 3: Food intolerance is not an allergy
When a cat cannot digest a particular food causing gastrointestinal discomfort, we call it a food intolerance. This is not an allergic reaction because it does not involve the immune system.
The most common food intolerance in cats (and many people) is cow’s milk. Milk contains a type of sugar called lactose. Adult cats cannot process lactose very well, so ingesting milk may cause stomach upset and diarrhea. But this is not a food allergy, the body does not recognize lactose as a hostile medium, and it cannot digest it.
Fact 4: Gastrointestinal symptoms
Food allergies in cats often cause chronic vomiting and sometimes diarrhea. Of course, not every case of vomiting or diarrhea indicates a food allergy, but once other causes have been ruled out, food allergy often becomes the direction of diagnosis.
Fact 5: Skin problems
It may surprise you to know that many times food allergies are reflected in the cat’s skin, not the stomach. Veterinarians call these CAFRs an acronym that stands for Cutaneous (Skin) Adverse Food Reactions.
Symptoms of CAFR include an itchy rash, bumps, scaly skin, swelling, hair loss, sores, hot spots, inflammation, and sometimes vomiting and diarrhea. Itching occurs primarily on the head, neck, face, ears, feet, and armpits and affects the entire body. Your pet’s eyelids may be swollen, and you may notice your pet constantly scratching, shaking or rubbing their head, or licking their feet more frequently.
According to a recent study, 3-6% of skin problems in cats are caused by food allergies. Another study found that 6% of food allergy cases exhibited skin inflammation in one veterinary hospital and 10% allergic skin reactions.
Fact 6: Food allergies can take time to develop
Food allergies don’t happen overnight. No one knows precisely why allergies occur, but we do know that in some cases, symptoms progress slowly over months or even years. Just because your cat has been eating the same cat food for years without problems doesn’t mean they haven’t developed an allergy recently.
Fact 7: The best way to diagnose a food allergy is to change the diet
Although some blood and saliva tests can be performed, the only way to confirm a food allergy is to eliminate the potential allergen from your cat’s diet.
Your veterinarian may recommend a diet based on one or two ingredients for a few weeks to see if the symptoms improve. If they do not, you will have to try a different limited ingredient diet to see if that helps. Once you find the culprit, your veterinarian may recommend temporarily reintroducing it to see if the symptoms return. If this happens – you know what types of foods your cat should avoid from now on.
Fact 8: Prescription foods containing hydrolyzed proteins can help diagnose (and treat) food allergies
Your veterinarian may recommend a hydrolyzed protein diet as a form of elimination diet. The proteins in these formulas are broken down into smaller molecules that are less likely to cause allergic reactions.
Fact 9: Cat diets with limited ingredients are not necessarily hypoallergenic
For some cats, all that is needed is a trace amount of allergen to trigger a reaction. Eliminating all traces of harmful foods can prove to be a challenge for some types of commercial cat foods.
Unfortunately, store-bought food with limited ingredients is often not “pure” enough for allergic cats. Pet nutritionist Dr. Martha Cline explains that the same production line is often used to make various cat foods. For example, a limited batch of chicken-based food may be contaminated with beef from the same cable used to create an earlier cat food set.
Dr. Cline recommends using a veterinarian-approved hypoallergenic food during food trials. Homemade foods are also an option, as long as cat owners are careful to avoid cross-contamination with other types of foods.
Fact 10: Symptoms of food allergies do not disappear overnight
Just as it takes time for allergy symptoms to build up, it can also take a while to go away. Once the allergen is removed, most affected cats will show improvement within a few weeks, with some taking up to 12 weeks. According to this study, 90% of cats will show signs of improvement within 8 weeks.
If your cat suffers from chronic vomiting or skin problems – especially in the head and neck – don’t try to diagnose food allergies yourself. Many other conditions can cause vomiting and skin problems. More urgent medical issues must be ruled out before addressing food allergies, so if your cat develops any of these symptoms, talk to your veterinarian and do not delay professional medical care.