Wet Food Allergy in Cats

Cats with food allergies often develop uncomfortable and unsightly skin conditions, and although wet food does not pose a higher incidence of allergic reaction than dry food, allergies to the ingredients in any type food may arise. An elimination diet is the veterinary gold standard for accurately identifying which allergen is distressing your feline. This process is often time-consuming, requiring several weeks to months of treatment, however, it is still the most popular and accurate method available today to deduce which ingredient is causing the patient’s reaction.

Cats can develop uncomfortable and unsightly skin conditions due to allergies to any ingredient, including the ingredients found in wet cat food.

Symptoms of food intolerance, including abdominal pain, digestive distress, and gurgling sounds from the digestive system, frequently precede or accompany an actual allergic attack. Symptoms of food allergies are typically dermal and tend to originate on the head and neck on cats and include signs such as:

• Acute moist dermatitis
• Crusty papules on skin
• Excessive drooling
• Hair loss
• Itchy skin
• Lesions on skin

Types

Although allergies may develop to any ingredient present in your cat’s wet food, some ingredients are more likely to generate a response than others. The most familiar food triggers for feline allergies can include:

• Beef
• Corn
• Dairy products
• Eggs
• Fish
• Lamb 
• Seafood
• Soy
• Wheat gluten

Although wet cat food does look and smell like it is mostly made of some form of meat or meat byproduct, the truth is that many brands of wet cat food may include any of these ingredients, including wheat and corn. Cats can also develop allergies to the preservatives used to keep cat food fresh. Although preservatives are required to prevent rancidness in dry cat food, wet cat food is kept in an airtight container, so may be manufactured without the same preservatives. If employing wet food in order to design an elimination diet, you may want to choose food with no additional preservatives.

Food allergies are caused by an abnormally intense defensive response to a specific protein that makes up an ingredient in the cat’s diet which its immune system has identified as an intruder.  The gastrointestinal tract houses approximately 60-70% of the cells that make up the feline immune system. Foods are broken down into the smallest possible parts, known as amino acid, by the process of digestion.

Once broken properly down into amino acids, these proteins are then absorbed by an enterocyte, a specialized type of white blood cell, which then transports the amino acid into the bloodstream for use by the body. Proteins that are incompletely broken down are identified as dangerous intruders rather than essential nutrients, and the enterocytes attack it rather than absorb it. When exposures to the protein are repeated, the immune system reaction becomes increasingly aggressive, and the symptoms of the allergy intensify.

Skin reactions exhibited by allergic felines closely mimics other skin disorders such as bacterial skin infections, fungal infestations, and even mites, and most veterinarians will choose to collect samples of the skin to perform a cutaneous cytology, a process in which the technician examines the sample under a microscope to see if any other organisms or malformations can be identified. Allergies are typically suspected where there are no problematic micro-organisms found, although determining the trigger for the allergies can be more challenging. Although both intradermal and serum assessments are available for cats that have developed allergies, they are not generally as reliable for detecting allergies relating to food. 

The most commonly used tool for the veterinary diagnosis of food allergies is the elimination diet, a time-consuming but effective method in which the cat’s daily diet is switched to either a limited ingredient commercial cat food or a specialized hypoallergenic food. Some cat owners may choose to feed their cat a homemade diet of unseasoned meats, although this should only be done with the advice of a feline nutritionist in order to ensure the cat gets the appropriate ratio of nutrients to best support their system. Elimination diets are frequently made up of novel ingredients which are defined as any proteins or carbohydrates that are not currently included the cat’s current diet, preferably ingredients that the animal has never been introduced to.

Several weeks of the elimination diet may be required in order to reveal which particular ingredient is causing the patient’s distress, and during this time your cat will generally continue experiencing many of the symptoms of the allergy. Corticosteroids are frequently employed to reduce swelling and antihistamines are often an effective method to calm itching and prevent scratching. However, both of these treatments may make uncovering the problem ingredient in your cat’s wet food more difficult by masking the symptoms of the allergy. 

Because of this, many veterinary professionals choose to delay prescribing these types of medication until they are certain of the results of the elimination diet. Once the specific allergen has been identified, it should be eliminated entirely from the cat’s diet; this means that supplements and treats should be carefully monitored to ensure that the offending ingredient is not included.

Cats that experience allergic reactions that affect the skin quite often develop secondary skin infections and antibiotics are prescribed to either combat or prevent this complication. Additional daily supplements, including probiotics and Omega-3 oils, are frequently recommended for all sorts of allergies in order to support the immune system and to assist your cat’s body in handling any accidental exposures to the allergen as well as helping to prevent the cultivation of new allergies.

Food allergies are not curable, however, the symptoms typically cease once the allergen is completely eliminated from the animal’s diet. Caution must be maintained in regards to the types of treats or flavorings that are offered to the cat as subsequent exposures of even small amounts of the allergen are capable of causing a relapse. Felines that experience an allergic response to one ingredient are more likely to eventually develop new allergies, possibly including allergies to the ingredients in the replacement diet itself. Veterinary professionals are split on their approach to combat this situation, with some doctors promoting a single source of food unless new symptoms develop, and others maintaining that a steady rotation of a few novel foods is more beneficial in the long run.