How do I know if my dog has a food allergy?

Food allergies in dogs are frequently diagnosed but also frequently misdiagnosed — many owners assume their dog has a food allergy when environmental allergies (pollen, dust mites, mould) are actually to blame. Understanding the difference is essential before changing your dog's diet.

True food allergy vs. food intolerance

A food allergy is an immune system response to a specific protein. It typically causes consistent symptoms that occur every time the food is eaten, regardless of season.

A food intolerance is a digestive reaction (not immune-mediated), causing gastrointestinal symptoms like diarrhoea, vomiting, or gas.

Common allergens in dogs

The most frequently implicated ingredients are:
1. Beef — the most common dog food allergen
2. Dairy
3. Chicken
4. Wheat
5. Lamb (increasingly common as it has been used as a "novel protein" in many allergy diets)
6. Soy
7. Eggs

Symptoms of a food allergy

- Skin symptoms: non-seasonal itching (paws, face, ears, groin, armpits), recurring ear infections, hair loss, hot spots
- GI symptoms: chronic or intermittent vomiting, soft stools or diarrhoea, gurgling sounds
- Year-round symptoms — food allergies do not worsen in spring/summer like pollen allergies do

The only reliable test: an elimination diet

Blood and skin allergy tests for food in dogs have poor sensitivity and specificity — they produce many false positives. The gold standard is an 8–12 week elimination diet trial using either:

1. Novel protein and carbohydrate — ingredients your dog has never eaten (e.g. rabbit and potato, or kangaroo and oat)
2. Hydrolysed protein diet — proteins broken into fragments too small to trigger an immune response

During the trial, your dog must eat only the trial food — no treats, chews, flavoured medications, or table scraps.

Flovvi tip

Track your dog's symptoms daily in Flovvi during the elimination trial. Consistent symptom logging is essential to identifying which food is the trigger during the re-introduction phase.