Food allergies, sensitivities, and when to see a vet

Itch is a sign, not a shopping category

A dog that scratches, licks its paws, shakes its head, or leaves a trail of stool accidents is telling you something is wrong. It is not telling you which bag to buy. Food allergy, food intolerance, fleas, mites, pollen, contact irritants, infection, hormone disease, and several other problems can look similar from the sofa. This site will not sort those for you. It will not name a protein as the usual culprit, and it will not treat a change of bag as a diagnosis. The only responsible first move, when signs are more than a single evening of loose stool after stolen food, is a veterinarian.

A food allergy, in the sense owners usually mean — an immune-mediated reaction to something in the diet — is uncommon relative to how often the phrase is used in an aisle. That is a qualitative caution, not a statistic this page will invent. What is well established in veterinary practice, and what this site will repeat without embroidery, is that confirmation relies on a veterinary elimination diet, not on a shop-aisle guess and not on a standalone blood test. Hair samples sold as allergy tests do not replace that process either. If a laboratory printout has already arrived in your kitchen, take it to the clinic before you throw out the current food.

The RSPCA Knowledgebase still frames everyday feeding: the basis of the diet should be a high-quality, balanced, premium commercial food appropriate for life stage and health; foods should meet Australian Standard AS 5812 or equivalent; veterinary advice should be sought. “Premium” is not a regulated allergy grade. It does not mean hypoallergenic. What makes dog food premium is the longer refusal to let marketing language do clinical work.

What you might notice — and what you must not conclude

Owners often report itch, recurrent ear trouble, paw licking, face rubbing, vomiting, diarrhoea, or a combination. Those are reasons to book a veterinarian. They are not a list from which you may diagnose food allergy at home. Seasonal itch that improves in winter, fleas seen on a comb, a dog that scoots because of anal-sac irritation, or a puppy with worms can all mimic a “food” story. Only the clinic can examine skin, ears, and the abdomen, and only the clinic can decide whether diet is even the next investigation.

Urgent signs are a different category. Facial swelling, hives that spread quickly, collapse, laboured breathing, repeated vomiting, blood in vomit or stool, a swollen tight abdomen, or a dog that cannot stand are not “watch and switch food” moments. They are same-day veterinary moments, and in severe cases they are emergency-clinic moments. Do not administer leftover human antihistamines or leftover tablets from another pet. Do not induce vomiting unless a veterinarian has told you to. This page is not a treatment plan.

If you think the dog has eaten chocolate, grapes, raisins, sultanas, onions, garlic, macadamia nuts, or another known problem food, ring a veterinarian or poisons information service even if the dog still looks well. The RSPCA Knowledgebase lists those among foods that are toxic to dogs. Toxicity is not allergy. Both can look dramatic. Neither is something you investigate with a new variety of kibble.

Why the aisle cannot run an elimination diet

An elimination diet is a clinic-designed period in which the dog eats only the foods the veterinarian has allowed, for the length of time the veterinarian has set, with no extra chews, no flavoured tablets unless approved, no stolen scraps, and no “just this biscuit.” The point is control. A supermarket rotation has no control. Two bags can share the same protein, the same fat source, and the same additive even when the variety names differ. Treats undo the trial in an afternoon. A flavoured chew, a leftover sausage, or a stuffed toy can be enough.

PFIAA’s note on variety names is the practical illustration. Under AS 5812 guidance, if a meat is 25% or more of the meat component and is the main meat, it may be used as the variety name. That is a minimum condition for using the name. It is not a promise that the named meat is the only meat, and it is not a promise that the rest of the meat component is absent or irrelevant. How to read dog food labels is how you then read the descending ingredient list (except water), the adequacy statement, and the additive line, including sulphites.

If a veterinarian has asked you to avoid a particular ingredient, you need that full list, and you may need to ask the manufacturer named on the pack how the recipe is made and whether other meats are processed on the same line. You cannot see that from a photograph of a paddock. You also cannot see it from the word “limited.” Limited is not an Australian legal grade.

Grain-free, single-protein, and “sensitive” are marketing clusters in the same family as premium. They may describe a recipe honestly, or they may only describe a tone of voice. They are not a diagnosis of grain allergy, which households often assume and clinics often have to unwind. Do not remove grains on a hunch. Do not add grains on a hunch. Let the elimination diet, if one is indicated, decide what the dog actually eats.

Completeness still matters while you investigate

A dog with skin or gut signs still needs a complete ration unless the veterinarian has prescribed otherwise. Australian Standard AS 5812 (Manufacturing and marketing of pet food — cats and dogs), latest published edition AS 5812:2023, remains the manufacturing and marketing standard. PFIAA still describes the label cluster: PET FOOD ONLY or similar, species illustration, protein and fat composition, nutritional adequacy, feeding directions, date information, ingredients in descending order by weight except water, additives including sulphites, manufacturer name and address, and net weight. An elimination diet that consists of random lean meat from the fridge is not automatically complete. The RSPCA Knowledgebase does not recommend bones and raw meat as a feeding basis, advises against milk, and advises avoiding sulphite-preserved pet meat, mince, rolls and sausages because of incidents of thiamine deficiency. A homemade “plain” diet without veterinary direction can create new problems while you chase old ones.

Veterinary prescription diets exist for a reason. If the clinic hands you one, that product’s instructions outrank a complete-and-balanced bag that looks more ordinary. Do not mix the prescribed food with leftover supermarket kibble to “make it tastier” unless the veterinarian has said you may. Palatability tricks are how trials fail.

Wet versus dry dog food may still be a texture choice inside a trial if the clinic agrees. Format is not an allergy category. Moisture can help a dog that is reluctant to eat; it does not confirm a diagnosis.

Switching food is not the same process

Switching dog food is for an ordinary change of complete food in a well dog, usually over about a week or longer, as RSPCA Victoria suggests for a gradual diet change. An elimination diet may use a different pace, a different food, and a much stricter rule about extras. Do not run both ideas at once. Do not start an ordinary switch because a friend mentioned chicken, then start a second switch because the first one did nothing by Friday.

During any change, the ordinary cautions remain. Adult dogs should be fed at least twice daily, should not be exercised immediately before or after eating because of bloat risk (especially deep-chested dogs), and should have fresh water always. Puppies still need frequent meals; puppy food is the growth guide. Older dogs still need a clinical eye on muscle and teeth; senior dog food is the ageing guide. Feeding guides remain starting points. Body condition still needs a human hand on the ribs.

If stools explode or vomiting starts during a change, stop adding the new food and call the clinic. That may be simple dietary upset, or it may be something else. You will not find out from the next variety name.

Household habits that look like investigation and are not

Keeping a diary of itch, stools, treats and medication is useful for the veterinarian. It is not a diagnosis. Photographs of ears and skin, a list of every chew in the house, and the packs you have used in recent months are the kind of ordinary evidence a clinic can use. What is not useful is an expanding pile of half-finished bags, a rotation of toppers, or a calcium powder added to “support the skin.” Calcium powder supplements should not be given unless a veterinarian directs.

Do not test the dog with leftover cheese, milk, peanut products, or “a bit of whatever we are eating.” Milk is not advised. Many human foods are unsafe. A sensitivity trial that uses the family dinner is not a trial.

If you suspect the commercial food itself has caused a serious problem — a batch that several pets ate before they became ill, a neurological change, or an acute allergic-looking emergency — the dog still goes to the veterinarian first. Reporting can then proceed through the AVA PetFAST veterinary reporting pathway. That pathway is for clinicians. It is not an online form that replaces examination, and it is not a public ranking of products. This site will not name brands and will not keep a scoreboard.

After a clinic has given you a plan

Follow it for the whole period, including the unexciting weeks when the skin looks only slightly better. Elimination diets fail because someone offers a biscuit, or because a second person in the house did not know the rules. Tell every carer. Feed other pets separately. Pick up dropped food. Ask the veterinarian before you use a new flavoured preventative, a new chew, or a new toothpaste.

When the clinic later asks you to challenge the diet — to reintroduce a food on purpose — that step is part of diagnosis. It is not an invitation to experiment at home on a different timetable. If signs return, you report them; you do not add a third protein the same night.

There will be dogs whose itch is not food. There will be dogs whose diarrhoea is not food. There will be dogs who need both dietary and non-dietary care. A calm owner is one who lets the veterinarian say which. The aisle will keep offering sensitive, limited, grain-free and premium as if they were clinical terms. They are not. The checkable objects remain a complete food you can read, an elimination diet you did not invent, and a clinic you ring when the dog is not well.