Food allergy in cats: head and neck pruritus
2-year-old indoor domestic shorthair cat with intense non-seasonal pruritus of the head, pinnae and neck, with excoriations and crusts. It vomits occasionally. It has been on an effective flea product for 3 months, as has the other cat in the house; cytology shows only inflammation and some cocci.
What is the most appropriate next step?
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A. Depot methylprednisolone acetate and a check-up in 3 months
It would temporarily control the signs, but it diagnoses nothing, and repeated depots increase the risk of diabetes and heart failure in cats.
B. Environmental allergen serology to start immunotherapy
Food allergy must be ruled out before considering environmental allergens. Serology does not diagnose allergy; it only helps choose allergens.
C. Treat the secondary infection and start a strict elimination diet (hydrolysed or novel protein) for 8 weeks
Correct. Head and neck pruritus is a typical pattern of feline food allergy, and concurrent GI signs make it even more likely. With flea control properly done, an elimination diet with challenge is the key diagnostic step.
D. Deep skin scraping to rule out Demodex cati as the main cause
Scrapings are reasonable in the initial work-up, but feline demodicosis is uncommon and would not explain this picture with GI signs better than food allergy.
lightbulb Key takeaway
In cats, change the diet gradually and make sure it eats it: a cat that stops eating can develop hepatic lipidosis. If there are other cats at home, all must eat the same food or be separated to avoid food sharing.
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Updated: October 31, 2026 · Educational content for veterinary professionals. It does not replace current clinical guidelines or the judgement of the attending veterinarian.