Food Allergies vs. Sensitivities in Cats: What’s the Difference?

Britt
by Britt
Photo credit: New Africa / Shutterstock.com

You know your cat better than anyone. You’ve memorized the way they nap in their favorite sunspot, the sound of their little meow asking for breakfast, and the gentle purr that starts when you scratch under their chin. But recently, something has been off. Maybe you’ve noticed they are scratching a lot, their usually glossy coat is starting to look dull, or they are struggling with a digestive issue that seems to come and go. Whatever the concern, your first instinct is to find out why.


If you’re here, you likely suspect the recent changes in your cat might be related to their food. That’s a great start – but what next?


It’s easy to get lost in the sea of information, especially when you start hearing terms like “food allergy” and “food sensitivity” tossed around with no real definition of what they actually mean. If your cat’s condition is food-related, understanding the difference between these two conditions is the most important step you can take toward a real solution.


This post will break down the science behind food allergies and sensitivities, help you recognize the signs of trouble, and outline a plan of action for working with your vet to get your kitty feeling their best again.


Food Allergy vs. Food Sensitivity


To understand how to help your cat, you need to know what’s happening inside their body after they eat. While the symptoms can often look similar, a food allergy and a food sensitivity are two very different conditions. The key difference lies in the body’s reaction to the food.


A food allergy is an immune system reaction.  This happens when your cat’s body mistakes a specific protein in a food as a dangerous invader. This mistaken identity triggers their immune system to launch a defensive attack, creating antibodies to fight off the perceived threat. The result is a chain reaction that releases inflammatory chemicals, like histamine, throughout the body. These chemicals are responsible for the symptoms we see, like intense itching, inflamed skin, ear infections, digestive problems, and other more severe complications.


Allergies often develop after being exposed to an ingredient over a prolonged time. For example, a cat who has been eating the same chicken-based food for years might suddenly develop an allergy to the chicken protein.


In contrast, a food sensitivity, or food intolerance, is strictly a digestive issue. The immune system is not involved. With a sensitivity, your cat’s digestive system simply struggles to break down and process a particular ingredient. This could be because they lack the specific enzyme necessary to break down the food or because the ingredient itself irritates their digestive tract. Either way, it leaves them feeling “off.”


Luckily, because a sensitivity isn’t an immune reaction, the symptoms are generally less severe and are primarily confined to the digestive system. You’ll typically see vomiting, diarrhea, gas, or general discomfort in the abdomen. While a sensitivity isn’t going to affect the entire body like a food allergy can, it can still be very uncomfortable for your cat and significantly impact their quality of life.


Food sensitivities can be immediate or can build up over time, gradually getting worse as they are exposed to the trigger. It’s always important to distinguish this from an allergy so you can take the right steps to give your cat much-needed relief.


Red Flags to Watch Out For


Noticing when something is “off” with your cat is one of the most critical parts of being a responsible pet parent. However, the symptoms of a food allergy or sensitivity can be sneaky and often overlap with other conditions. Knowing what to look for and how to distinguish between the two conditions can make a significant difference.


Common Symptoms Shared by Both


Many of the symptoms of food allergies and sensitivities are similar, which is why it can be so difficult to tell the two apart. The most frequent signs you may notice include:


  • Skin Issues: This is one of the most common signs of trouble. You might see your cat scratching or licking excessively, which can lead to hair loss, red and inflamed skin, or small scabs, primarily around their head, neck, and ears.
  • Digestive Distress: This includes vomiting, diarrhea, gas, or a general lack of appetite. While these can be caused by many things, when they are chronic and not easily explained, they may point to a food-related issue.
  • Chronic Ear Infections: Recurring ear infections that don’t respond well to treatment or keep coming back are a classic sign of an underlying allergy.


Recognizing Symptoms of a True Food Allergy


While allergies can present with digestive issues, they often manifest with more widespread and intense symptoms due to the full-body immune response.


  • Severity and Specific Location: The itching from a food allergy tends to be more severe and often localized to the face, ears, and neck. Constant scratching can cause damage to the skin, leading to secondary infections.
  • Systemic Effects: In rare cases, a true allergic reaction can also lead to respiratory problems like sneezing or wheezing. You may also notice swelling, particularly around the face. Regardless of the cause, if your cat ever has difficulty breathing, it should be treated as an emergency requiring immediate veterinary attention.


Symptoms More Indicative of a Food Sensitivity


A food sensitivity, or intolerance, may involve some minor skin irritation. However, the symptoms are much more focused on the digestive tract.


  • Gastrointestinal Problems: With a sensitivity, diarrhea and vomiting are often the main concerns. The symptoms are the direct result of the body’s inability to properly digest the specific food or ingredient. These symptoms won’t typically be accompanied by the intense, widespread itching that is often seen with a food allergy.
  • Less Widespread: Unlike an allergy, a sensitivity is generally confined to the digestive issues, meaning you are less likely to see any larger-scale skin reactions or other body-wide symptoms.


Many of these signs can also be caused by other problems, such as hairballs, eating something they shouldn’t, or switching foods too quickly. They could also be a sign of intestinal parasites or health concerns, like pancreatitis, colitis, or a blockage caused by a foreign body. While you should avoid jumping to conclusions, the only way to know for sure what is causing your cat’s problems is to make an appointment with your veterinarian to get a proper diagnosis.

Photo credit: Rido / Shutterstock.com

What to Do When You Suspect an Issue


Recognizing that something is wrong with your cat can be distressing. After all, we all want nothing but the best for them! But taking the right steps will put you on the path to a solution and the relief your kitty needs. Instead of trying to solve the problem alone, the best (and fastest) approach is to partner with your vet. Together, you form the team your cat needs in their corner.


Begin by scheduling an appointment. While this isn’t a time-sensitive emergency in most cases (unless there are signs of respiratory problems), you also don’t want to wait too long. Left untreated, your cat’s food-related issues will cause pain and discomfort and may, in time, escalate into something more serious.


During your appointment, your vet will do a thorough physical exam and also ask you questions to create a detailed history. Try to have as much of the following information with you as possible:


  • What are the specific signs you’ve seen (scratching, vomiting, etc.)?
  • When did the symptoms start? How often do they occur?
  • Have there been any recent changes at home that could be causing stress? Any changes that could trigger irritation (new laundry soap, new cleaning product)?
  • List every food, treat, and supplement your cat consumes. Be as specific as possible, including brand names and flavors.


Before jumping to the conclusion that the problem is food-related, your vet will need to rule out other possible causes. They may perform various tests, such as skin scrapings, blood work, or a fungal culture, to eliminate these other explanations.


The Elimination Diet


If your vet’s findings are pointing toward a food-related problem, they will likely recommend an elimination diet. This is considered the “gold standard” for diagnosing a food allergy or sensitivity, both confirming that it is the problem and helping to identify the offending ingredient.


This is a precise and methodical approach that will require patience and strict dedication to stick to the process (no cheating). Here’s how it works:


  1. Select a Novel or Hydrolyzed Protein Diet: Your vet may prescribe a specific diet, or you may be able to work together to find one that meets your pet's needs. A novel protein is one your cat has never eaten before, like duck or venison. A hydrolyzed protein is one in which the proteins are broken down into particles that are too small for the immune system to recognize as a threat.
  2. Strict Trial Period: For a period of 8 to 12 weeks, you must feed only this food. This means no treats, no table scraps, no flavored medications, and no other foods. Even the smallest amount of another food can ruin the entire trial.
  3. Monitor and Observe: During this period, you’ll need to carefully monitor your cat for an improvement in their condition. If the symptoms improve, it’s a good sign that an ingredient in their old diet was the problem. If they don’t improve, it’s likely not their food causing the issues.
  4. Gradual Reintroduction: In the final phase, you will slowly reintroduce the ingredients of your cat’s diet one at a time. If the symptoms reappear after adding a specific ingredient back in, you have found the culprit. This confirms the diagnosis and allows you to move on to managing the condition long-term. Keep in mind that there could be more than one ingredient causing trouble.


This whole process may need to be paired with additional treatments to address secondary issues, like a skin infection from excessive scratching. Your vet will let you know if further changes or medications are needed.


How to Manage Food Allergies or Sensitivities


Once you have successfully identified the specific ingredient or ingredients leading to your cat’s reaction, you have all the information you need to give them a long, healthy, trigger-free life. To do this, you need to focus on managing their diet.


While it may seem overwhelming to remove a common ingredient entirely, plenty of high-quality alternatives are available to ensure your cat is eating a complete, balanced diet while avoiding any issues. There are three main ways people approach this: prescription diets (like Hill’s Prescription Diet i/d Digestive Care), limited ingredient diets (like Go! Solutions Sensitivities Limited Ingredient Grain-Free Duch Pâté), or home-cooked diets.


Management also goes beyond just the food your cat is given each day. You will need to become an expert label reader, constantly checking the ingredient list on all food, treats, and even dental chews. Single-ingredient cat treats, like PureBites Freeze-Dried Salmon Cat Treats (a favorite in our house), are a great option.


Many commercial products contain hidden allergens, such as chicken meal or fish oil. If you notice any signs of returning problems, it could be a new allergy or an accidental exposure. The sooner you catch it, the sooner it can be addressed to get your cat back on track once again.

Solving the Food Puzzle Doesn’t Have to Be Hard


Navigating the world of food allergies and sensitivities can feel like a maze, but it doesn’t have to be. By working with your veterinarian, taking a careful step-by-step approach to finding and eliminating the trigger, you can give your cat a better quality of life, one filled with comfort, tasty treats, and happy purrs.


If you suspect your cat is struggling with a food-related issue, please don’t wait. Schedule an appointment with your veterinarian today and take that first step towards a solution!  


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Britt
Britt

Britt Kascjak is a proud pet mom, sharing her heart (and her home) with her “pack” which includes her husband John, their 2 dogs – Lucifer and Willow – and their 3 cats – Pippen, Jinx, and Theia. She has been active in the animal rescue community for over 15 years, volunteering, fostering and advocating for organizations across Canada and the US. In her free time, she enjoys traveling around the country camping, hiking, and canoeing with her pets.

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