All knowledge
Knowledge hub
Allergies & Nutrition
Food allergies are over-diagnosed and skin allergies are under-diagnosed. Here's how to tell the difference, run a proper elimination diet, and feed to UK and EU nutritional standards.
Last reviewed: May 2026
Allergy vs intolerance vs atopy
- Food allergy — immune reaction (IgE) to a protein. Symptoms are consistent regardless of how much is eaten. Confirmed only by an elimination diet, not blood or hair tests.
- Food intolerance — non-immune reaction (e.g. lactose). Dose-dependent — small amounts may be fine.
- Atopic dermatitis — allergy to environmental things (pollen, dust mites). Often seasonal. ~80% of itchy dogs are atopic, not food-allergic.
Most common food allergens in UK dogs
| Protein / ingredient | % of food-allergic dogs | Notes |
|---|---|---|
| Beef | ~34% of food-allergic dogs | Most common single trigger in UK studies |
| Dairy | ~17% | Often misread as lactose intolerance |
| Chicken | ~15% | Frequently 'hidden' in lamb-and-rice diets as flavouring |
| Wheat | ~13% | Gluten enteropathy is a separate, breed-linked issue (Irish Setter) |
| Lamb | ~5% | Now common because 'novel' lamb diets of the 90s aren't novel any more |
| Egg, soy, pork, fish | <5% each | Less common but documented |
For cats the top three are beef, fish and dairy. Grain allergies in either species are far rarer than the marketing suggests.
Signs that suggest a food allergy
| System | What you'll see |
|---|---|
| Skin | Itchy paws, ears, face, armpits, groin. Recurrent ear infections. Hot spots. |
| Gut | Loose stools, mucus, frequent small motions (often 4+ a day), vomiting bile in the morning. |
| Behavioural | Scooting, excessive licking, sleep disruption, irritability. |
How to actually diagnose food allergy
- Rule out parasites (fleas, mites) and infections with your vet first.
- Strict 8-week elimination diet — a hydrolysed prescription diet (Royal Canin Anallergenic, Hill's z/d, Purina HA) or a single novel protein your dog has never eaten (e.g. venison + sweet potato).
- No treats, no flavoured toothpaste, no flavoured wormers, no scraps. Anything else breaks the trial.
- If signs resolve, challenge by reintroducing the original food. If symptoms return — food allergy confirmed.
- Provoke individual ingredients one at a time to identify culprits.
Blood and saliva tests sold online have been shown in peer-reviewed studies (Coyner & Schick 2019) to return positives on tap water and shaved hair. They are not diagnostic.
Life-stage feeding (FEDIAF aligned)
| Life stage | Duration | Feeding plan |
|---|---|---|
| Puppy (small breed) | Until ~9 months | 3 meals/day; complete puppy food (AAFCO/FEDIAF 'growth') |
| Puppy (large/giant) | Until 12–18 months | Large-breed puppy food — controlled calcium prevents skeletal disease |
| Adult dog | 1–7 years | 2 meals/day; FEDIAF 'adult maintenance' |
| Senior dog | 7+ years (4+ giant breeds) | Often lower calories, joint support; check kidney/liver bloods annually |
| Kitten | Until 12 months | Free-feed or 3–4 meals; complete kitten food |
| Adult cat | 1–10 years | Wet + dry mix; wet helps urinary health |
| Senior cat | 10+ years | Kidney-friendly, high-quality protein; annual bloods + blood pressure |
UK feeding standards & labels
- "Complete" — meets all nutritional requirements; safe as sole diet.
- "Complementary" — treats, mixers, toppers — not safe alone.
- FEDIAF — the European pet food industry body that sets minimum/maximum nutrient levels reputable UK brands follow.
- PFMA — Pet Food Manufacturers' Association — UK trade body; members publish nutrient analyses.
- BARF / raw — can be balanced when formulated by a qualified nutritionist; carries Salmonella, Campylobacter and antimicrobial resistance risk per a 2019 FSA review. Wash hands and surfaces, never feed raw to immunocompromised households.
Body condition score — the most useful tool you'll ever use
Ideal weight is a 4–5 out of 9: ribs felt easily without pressure, visible waist from above, abdominal tuck from the side. PFMA estimates 51% of UK dogs and 44% of UK cats are overweight — even a 10% body-weight loss meaningfully extends lifespan in dogs.