Elimination Diet

A food trial is the only way to confirm or rule out food allergy. It requires strict compliance for 8–12 weeks.

Why it matters

There is no blood or skin test that reliably diagnoses food allergy. An elimination diet trial is the gold standard.

Duration

• At least 8 weeks, often 10–12 weeks.
• Many allergic dogs take 5+ weeks to improve.
• Partial improvement by week 4–5 is a good sign; continue to 12 weeks if needed.

Diet choice

• Veterinary prescription diets only — Novel protein or hydrolyzed.
• Over-the-counter “limited-ingredient” diets are unreliable due to cross-contamination.
• If one diet fails, a second novel protein may be tried.

Strictness

• No other food or flavour — No treats, flavoured medications, milk bones, table scraps, or supplements.
• Even a small cheat can invalidate the trial.
• Use approved pill pockets or pieces of the trial diet as treats.

What to track

• Daily itch score — Log in Track the Itch.
• GI signs — Vomiting or diarrhoea; up to 50% of food-allergic dogs have GI signs.
• Compliance — Note any accidental exposure.

Challenge phase

If itch improves on the trial, your vet may reintroduce the original diet or suspect ingredients for 1–2 weeks. If itch returns, food allergy is confirmed. If no flare, food allergy is unlikely and environmental allergy testing may follow.

For your vet
Track the Itch itch logs over the trial period support diet trial assessment. Ensure Cytopoint or other long-acting antipruritics are accounted for (extend trial if needed).