Feeding & Nutrition

My cat itched constantly. I switched foods three times in six months. The itching continued. A vet diagnosed food allergy finally — but not to any of the proteins I'd eliminated. It was chicken, the most common allergen, present in every diet I'd tried because I assumed 'novel protein' meant safe.

Food allergies in cats are uncommon — estimated at 1-10% of dermatological cases. Most itchy cats have flea allergy dermatitis, environmental allergies, or infection. Food allergy should be a diagnosis of exclusion, not a first assumption.

When food allergy is suspected, elimination diet trials are the diagnostic standard. Eight to twelve weeks on a prescription hydrolyzed or novel protein diet, with no treats, no flavored medications, no table scraps. Even accidental protein exposure resets the clock. Compliance is essential.

Common allergens are the most common proteins: chicken, beef, fish, dairy. The irony is that cats allergic to chicken often tolerate duck or rabbit. But without proper diagnosis, switching to another common protein doesn't solve the problem — it just changes the symptom pattern.

Food allergies develop over time. A cat can tolerate a protein for years, then suddenly react. Previous tolerance doesn't guarantee future tolerance. This unpredictability makes diagnosis essential before arbitrary diet changes.