Food allergies in cats occur when their immune system mistakenly identifies a food ingredient as harmful. This triggers an overreaction each time the cat consumes that specific ingredient, even if they’ve eaten it before without issue. It’s important to note that a cat must have been previously exposed to a food allergen to develop an allergy to it.
The most visible signs of Cat Food Allergies often manifest on the skin. Affected cats can experience intense itching, leading to excessive scratching, grooming, and the development of secondary skin infections and painful sores. Beyond skin issues, food allergies can also disrupt the digestive system, resulting in gastrointestinal problems like diarrhea and vomiting.
While cat food allergies are not widespread, they are a significant concern for some felines. Statistics suggest that approximately 1% of the total cat population suffers from food allergies. However, among cats exhibiting chronic itching, this number rises considerably, with up to 15% potentially affected by food allergies. In cats presenting with both itching and gastrointestinal distress, food allergies could be a factor in as many as 42% of cases. Interestingly, food allergies in cats don’t appear to be linked to specific age, gender, or breed predispositions.
Recognizing the Symptoms of Cat Food Allergies
Persistent itching is a hallmark symptom of food allergies in cats, often described as non-seasonal, meaning it doesn’t improve or worsen with changes in the time of year.
In addition to itching, cat food allergy symptoms can include:
- Excessive licking
- Frequent scratching
- Overgrooming habits
- Increased biting at the skin
Itching associated with food allergies can affect any part of a cat’s body, but it’s most commonly observed around the head and neck region.
Visible skin lesions are also frequently present and may take various forms, such as:
- Miliary dermatitis (small crusty bumps on the skin)
- Skin redness (erythema)
- Papules (small raised bumps)
- Self-inflicted injuries (sores and abrasions from biting, scratching, or licking)
- Alopecia (hair loss due to overgrooming)
- Skin ulcerations
- Plaques (raised, circular patches on the skin)
Less frequently, cats with food allergies may exhibit gastrointestinal symptoms. These can include diarrhea and/or vomiting, indicating digestive upset related to the food allergy.
Pinpointing the Causes of Feline Food Allergies
Food allergies in cats can emerge at any stage of life. Surprisingly, they can even develop to foods a cat has consumed for years without any prior reactions. The majority of confirmed food allergies in cats are triggered by an abnormal immune response to proteins found in food. While numerous food substances can potentially cause allergies, certain ingredients are more commonly identified as culprits.
Common food allergens in cats include:
- Beef
- Fish
- Chicken
Less common, but still recognized, food allergens for cats are:
- Wheat
- Corn
- Dairy products
- Lamb
- Eggs
- Barley
- Rabbit
Diagnosing Cat Food Allergies: What to Expect at the Vet
Veterinarians rely on a food elimination trial as the gold standard method to diagnose food allergies in cats. This process involves feeding the cat a strictly controlled hypoallergenic diet for a period of 8 to 12 weeks to monitor for symptom improvement. Adherence to this diet is critical, meaning no treats, flavored medications, or even certain medication capsules (like gelatin) can be given during the trial.
The selection of a truly hypoallergenic diet is personalized to each cat, depending on their previous food history. Ideally, a home-cooked diet using a novel protein source—one the cat has never eaten before—is considered. However, preparing a nutritionally balanced home-cooked diet long-term is complex and often impractical.
If the cat’s symptoms improve on the elimination diet, the next step is to reintroduce the original diet to see if symptoms recur. If symptoms return, confirming the food allergy, the cat is switched back to the hypoallergenic diet. Following this, individual ingredients from the old diet can be reintroduced one at a time, every two weeks, to pinpoint the specific allergen. If no reaction occurs after introducing an ingredient, it’s deemed safe for that cat.
Conversely, if symptoms reappear within 14 days of reintroducing a specific ingredient, it’s identified as an allergen and must be avoided in the cat’s future diet. This process of elimination and reintroduction is necessary to precisely determine which foods a cat is allergic to.
Alternatively to a home-cooked diet, commercially available novel protein or hydrolyzed protein diets are often recommended for elimination trials. If a cat improves on such a diet, it can be continued indefinitely as these commercial options are formulated to be nutritionally complete for long-term feeding.
It’s important to be aware that various allergy tests claiming to diagnose food allergies in cats are available, including blood, hair, and saliva tests. However, clinical studies have not validated the accuracy of these tests. Therefore, they are not considered reliable for diagnosing food allergies in cats.
Providing your veterinarian with a comprehensive diet history of your cat is crucial for guiding the food elimination trial. This history helps in choosing an appropriate hypoallergenic diet. Whether using a novel protein or hydrolyzed diet, selecting one based on ingredients the cat has not been previously exposed to is preferable.
It’s also worth noting that some food-allergic cats may not respond to the first hypoallergenic diet tried but may show improvement on a different formulation.
Treatment Strategies for Cat Food Allergies
The cornerstone of treating cat food allergies is feeding a diet completely free of the allergenic ingredient. The specific dietary options suitable for an allergic cat can vary widely. Prescription diets are often favored for elimination trials due to their stringent quality control and reduced risk of containing contaminant proteins, which can be a concern with over-the-counter cat foods.
Many cats experience significant itching when starting a hypoallergenic diet, so additional symptomatic treatment may be needed for initial relief. Low-dose corticosteroids, such as prednisolone, are frequently used to manage itching. If secondary bacterial or yeast skin infections are present, they must also be treated with appropriate antibiotics and/or antifungals, and repeated treatments may be necessary to fully resolve these infections.
Recovery and Long-Term Management of Food Allergies in Cats
Once a cat with food allergies is started on a suitable hypoallergenic diet, it can take up to 10 weeks for symptoms to fully resolve. During this period, it’s vital to ensure the cat has no access to any other food sources that could compromise the elimination diet. Managing food allergies in cats requires strict, lifelong adherence to the prescribed diet.
Supplementation is generally not recommended for cats with food allergies due to the potential for allergic reactions to ingredients in the supplements themselves. Moreover, high-quality hypoallergenic diets are formulated to be nutritionally complete and balanced, making supplements unnecessary. If a cat’s symptoms persist despite a strict dietary change, it’s essential to investigate other potential causes for their symptoms beyond food allergies.
Novel Protein Foods for Cats
[Novel protein foods for cats]
Hydrolyzed Foods for Cats
[Hydrolyzed foods for cats]
Featured Image: iStock.com/eclipse_images
WRITTEN BY
Leigh Burkett, DVMVeterinarian
Dr. Leigh Burkett was born and raised in Northeast Tennessee. She received her undergraduate degree in Biology from Wake Forest University…
