Dermatologic Food Reactions in Cats: Understanding, Diagnosing, and Managing

Dermatologic food reactions in cats involve hypersensitive immune responses to certain food substances, leading to non-seasonal reactions and symptoms such as excessive itchiness and scratching. It’s essential to differentiate between immune-mediated reactions and non-immunologic idiosyncratic reactions (food intolerance). Here’s an overview:

Symptoms and Types:

• Non-seasonal itchiness at any body location
• Poor response to anti-inflammatory glucocorticoids may indicate food hypersensitivity
• Gastrointestinal symptoms like vomiting, diarrhea, excessive gut sounds, and frequent bowel movements
• Skin issues including malassezia dermatitis, pyoderma, otitis externa, plaque, pustules, erythema, crust, scale, self-induced baldness, abrasions/sores, leathery skin, hyperpigmentation, hives, and giant wheals
• Pyotraumatic dermatitis (bacterial infection due to excessive scratching)

Causes:

1. Immune-mediated reactions:
   • Result from the ingestion and presentation of allergens (glycoproteins) either before or after digestion.
   • Sensitization may occur in the intestine or after absorption.
2. Non-immune reactions (food intolerance):
   • Result from ingestion of foods high in histamine or substances inducing histamine release.
   • Speculated that intestinal parasites or infections in juvenile animals may cause sensitization.

Diagnosis:

• Complete physical and dermatological exams.
• Blood tests (chemical profile, complete blood count, urinalysis, electrolyte panel) to rule out other causes.
• Food elimination diets with limited exposure to known proteins and carbohydrates.
• Clinical improvement may be seen in 4 to 13 weeks.

Important Considerations for Elimination Diets:

1. Taurine Requirement: Cats need a source of taurine in their diet to prevent illness.
2. Protein Over Carbohydrates: Protein should outweigh carbohydrates by about 90%.
3. Avoid Raw Meats: Due to bacterial contamination risks.
4. Challenge and Provocation Diet Trials:
   • Challenge with the original diet, and if signs return, perform a provocation diet trial.
   • Provocation trials involve adding single ingredients one at a time and observing for adverse reactions.

Treatment:

• Avoid any food substances that caused the signs to return.
• Antibiotics or antifungal medications if secondary infections occur.

Living and Management:

• Eliminate treats, chewable toys, and medications containing ingredients from the previous diet.
• Create a confined area if your cat spends time outdoors to prevent foraging.
• All family members must be aware of the test protocol and help maintain the test diet.

Cooperation and adherence to the prescribed diet are crucial for successful treatment. The diagnosis and management of dermatologic food reactions in cats require a systematic approach, involving elimination diets, challenge trials, and vigilant monitoring for signs of improvement or relapse. Regular veterinary guidance is essential throughout the process.