Understanding Cat Food Allergies: Causes and Solutions

Within the gastrointestinal tract, a protective barrier exists in most cats, which shields them from adverse reactions to the food they consume. This barrier's defense mechanisms encompass both physiological and immunological aspects. Abnormalities in the gastrointestinal defense mechanisms, such as a compromised mucosal barrier, increased antigen absorption, or defective immune regulation, can make your cat more susceptible to developing food allergies. However, it remains unclear which of these abnormal mechanisms is the primary cause of feline food allergies.

The exact pathogenesis of feline food allergies is still not fully understood. Type I hypersensitivity, mediated by a class of antibodies called immunoglobulin E (IgE), is thought to be a significant contributor to feline food allergies. In this allergic response, mast cells in the intestines detach and release inflammatory mediators.

Many proteins in food can act as allergens, with those containing high protein content often being the culprits. Complex proteins, which have numerous antigenic sites, are more likely to stimulate the immune system than smaller proteins. To trigger the release of mast cells, the attacking proteins must be large enough to connect two IgE antibodies.

The most common allergens associated with food allergies in cats include beef, dairy products, and wheat, which account for 66% of total allergy cases. According to recent surveys of North American veterinarians, allergies triggered by chicken, lamb, soy, eggs, pork, and preservatives make up only 22% of total allergy cases.

It is worth noting that while food additives are often suspected as allergens, there is little objective information to support this belief. More research is needed to confirm the role of food additives in feline adverse reactions.

Food allergies can manifest in various symptoms or diseases:

1. Skin disorders caused by food allergies are relatively rare in cats, with an incidence rate of 1%20% in small animals. Food allergies can occur at any age, including in kittens under six months old. Therefore, any cat younger than six months or older than six with itchy skin should be considered for a potential food allergy.

2. Nonseasonal pruritus, or itching, can be triggered by food allergies. These symptoms often have nothing to do with changes in diet. In fact, it is a common misconception that food allergies arise after a change in a pet's diet. Most pets diagnosed with food allergies have been fed the same food for many years, typically over two years. Any food can potentially cause an allergic reaction.

3. The clinical manifestations of feline food allergies include:

Commonly affected areas: mouth, nose, paws, armpits, groins, buttocks, and ears.

Local or systemic itching.

Outer ear inflammation, or otitis externa, which can sometimes be the sole symptom of food allergies.

Recurrent moist dermatitis.

Foot dermatitis, which refers to inflammation of the skin on the soles and between the toes.

Recurrent skin infections, including superficial bacterial infections (pyoderma) and yeast infections (malassezia dermatitis).

Variety of primary and secondary lesions, such as papules (small red bumps), skin redness, desquamation (wet lesions caused by selftrauma), hyperpigmentation, macules (red spots known as "bull'seye" lesions), and excessive sebum production.

Diarrhea, which occurs in only 10% of food allergy cases.

Symptoms of some diseases may be similar to those of food allergies. These diseases include atopic dermatitis, scabies, flea allergy, bacterial folliculitis, excessive sebum production, and malassezia dermatitis (yeast infection).

Secondary infections should be diagnosed and treated promptly. Veterinarians can use skin scrapings to collect samples for microscopic examination to test for the possibility of malassezia dermatitis, which can exacerbate itching or pruritus. The diagnosis of superficial pyoderma is based on the presence of papules, which are small red elevated lesions. All infected cats should undergo "skin scraping analysis" to rule out mange mites.