Quick answer: If you suspect your dog is allergic to a certain meat, don’t go for a blood test – not because it’s expensive, but because it’s inaccurate. The American College of Veterinary Dermatology (ACVD) does not recommend serum IgE/IgG food allergy testing, because healthy dogs producing antibodies to food proteins is a perfectly normal immune response, so the false-positive rate is extremely high. As of 2026, the elimination diet trial remains the only validated method for diagnosing food sensitivity. The correct approach has 6 steps:
- Step 1: Rule out the other causes first – flea allergy and environmental atopic dermatitis are far more common than food sensitivity, so trialling a food before sorting out fleas is a waste of time.
- Step 2: Understand why blood tests aren’t reliable – serum, saliva and hair tests are none of them recognised by veterinary dermatology.
- Step 3: Pick a single animal protein your dog has never eaten before – beef (34%), dairy (17%), chicken (15%) and wheat (13%) are the most common allergens and should be avoided.
- Step 4: Stick to it strictly for 8-12 weeks – no treats, no human food, no flavoured medications during this time. One slip-up and you have to start the count over.
- Step 5: Confirm with a rechallenge – feed the original food again, and only if the symptoms come back is it a confirmed diagnosis. Skip this step and all your effort goes to waste.
- Step 6: Long-term management after confirmation – identify the safe proteins and build a long-term feeding plan.
BC Pets carries 9 single-protein hypoallergenic dog foods, including AATU (80/20 recipe: duck, turkey, salmon, chicken), ACANA Singles (50% single meat: duck, lamb) and Wellness Simple (limited-ingredient recipe: salmon), giving you 5 single-protein choices in total – duck, turkey, salmon, lamb and chicken – priced from HK$218 to HK$1,162. The more protein types available, the easier it is to find one your dog has never eaten. But we must be clear: an elimination trial should be carried out under the guidance of a registered vet; this article only offers guidance on choosing a food and following the process.
Key takeaways (TL;DR):
- Blood tests aren’t expensive – they’re inaccurate: serum food allergy testing is not recognised by the American College of Veterinary Dermatology, and multiple peer-reviewed studies have found high false-positive rates and inconsistent results between different labs.
- Most itching isn’t a food problem: adverse food reactions account for only 10-25% of allergic skin disease in animals; flea allergy and environmental allergies are more common and must be ruled out first.
- Beef is the number-one allergen, not chicken: systematic literature reviews show that among confirmed cases, beef accounts for 34%, dairy 17%, chicken 15%, wheat 13% and lamb 5%.
- The value of a single protein is that it lets you control the variable: when a food contains only one animal protein, you can rule things out one at a time; a mixed-protein food simply can’t do this.
- You can’t cut corners on the 8-12 weeks: skin symptoms take time to improve, and feeding a single treat or one piece of human food midway means the whole trial has to start over.
- An over-the-counter food is not the same as a prescription hydrolysed food: hydrolysed-protein prescription diets are still the clinical standard, retail single-protein foods carry a risk of cross-contamination, and they suit a first attempt rather than being the sole option for severe cases.
Introduction: The blood-test money you want to save shouldn’t be spent in the first place
Many Hong Kong dog owners share a similar experience: the dog is constantly scratching, licking its paws, with recurring ear infections. You take it to the vet, get told to do allergen testing, and are quoted a few thousand dollars. Some grit their teeth and pay, get back a report listing a dozen “positive” foods, go home and cut everything out, and the dog still itches. Others feel it’s too expensive, give up altogether, and carry on feeding the same food.
Neither approach is ideal, and the first is especially a shame – because that money should never have been spent in the first place. According to veterinary dermatology consensus, serum IgE and IgG food allergy testing is not recommended for use by the American College of Veterinary Dermatology (ACVD). The reason is straightforward: healthy dogs producing antibodies to food proteins is a normal immune response, so a “positive” result does not mean an allergy. Multiple peer-reviewed studies comparing serum testing with the elimination diet (the diagnostic gold standard) have found that these tests have high false-positive rates, poor agreement between different commercial labs, and cannot reliably predict the true allergens that an elimination diet would reveal.
Over the same period, both the Merck Veterinary Manual and a 2023 review in the Journal of the American Veterinary Medical Association (JAVMA) confirmed that the elimination diet trial remains the only validated method for diagnosing food sensitivity. In other words, what you need is not a report, but a two-to-three-month trial carried out with enough discipline.
BC Pets has been operating in Hong Kong since 2009, with a shop in Fanling. Over the years we’ve seen far too many owners turn up with a test report asking “so which food should I buy”, and even more people who got halfway through an elimination diet only to undo it all by feeding a single treat. This guide breaks the whole process into 6 actionable steps, cites specific figures from veterinary literature, and explains the real role – and the limits – of single-protein dog food within it.
Important note: the elimination diet trial described in this article is a medical diagnostic procedure and should be carried out under the guidance of a registered vet. The vet’s role is not just to prescribe a food, but more importantly to first rule out other skin conditions (such as mange, bacterial or yeast infections, and endocrine disease) and to manage secondary infections during the trial. Simply switching food without treating an existing infection won’t improve the symptoms, and you’ll wrongly conclude it’s “not a food problem”.
Step 1: Rule out the non-food causes first, or no amount of food trialling will help
This is the step most people skip, and also the most fatal. There are many reasons a dog itches, and food sensitivity is only a small part of it. Research shows that adverse food reactions account for about 10-25% of allergic skin disease in companion animals; and even among dogs with confirmed atopic dermatitis, only a portion is food-triggered. In other words, for most itchy dogs, the problem isn’t in the food bowl.
| Cause | Typical signs | Seasonal | How to tell at first glance | Priority order |
|---|---|---|---|---|
| Flea/tick allergy | Itching concentrated at the tail base, lower back and inner thighs, with visible flea dirt | Peaks in the Hong Kong summer, but can occur year-round | Comb the lower back with a flea comb, then do the wet-paper test for flea dirt (it dissolves into a reddish-brown mark) | Top priority – thorough flea control must come first |
| Environmental atopic dermatitis | Paws, armpits, belly, face, ears | Often seasonal, worse when the seasons change or in humid weather | Symptoms vary with weather and location; usually first appears between 6 months and 3 years of age | Second priority – needs a vet assessment |
| Adverse food reaction | Recurring ear infections, paws, around the anus; may come with gut symptoms | Year-round, no seasonality | No change with the seasons and consistent itching all year is an important clue | Only trial after ruling out the two above |
| Contact irritants (mopping water, detergents) | Belly, paws and other parts that touch the floor | Linked to cleaning habits | Observe for two weeks after changing cleaning products | Easy to test, can be ruled out early |
| Skin infection (bacterial/yeast) | Red rash, greasiness, odour, hair loss | Worse in the humid season | Needs a vet to do a skin scrape or cytology | Must be treated at the same time, or it will mask the trial results |
Hong Kong’s climate makes this step especially important: summer humidity stays above 80% for long stretches, the flea season is long, and yeast infections are also common. Make sure your flea control is properly in place first – see our flea control / insect-killing products and outdoor flea-prevention products.
Tip: a handy self-check: is your dog’s itching seasonal? If it’s especially bad in spring and summer and clearly improves in autumn and winter, an environmental allergy is far more likely than a food sensitivity. Conversely, if the itching is consistent all year, especially alongside recurring ear infections and an upset stomach, then an adverse food reaction is more likely. This question doesn’t cost a cent, but it can save you months.
Step 2: Why aren’t blood tests reliable? It’s not just a question of cost
There are quite a few “pet allergen testing” services in Hong Kong, including serum, saliva and even hair tests, priced anywhere from a few hundred to a few thousand dollars. The problem is that the accuracy of these tests for food allergies is not recognised by the veterinary dermatology field.
| Test method | Purpose | Level of veterinary dermatology recognition | Main limitations |
|---|---|---|---|
| Elimination diet trial (8-12 weeks) + rechallenge | Diagnosing adverse food reactions | The only validated method (diagnostic gold standard) | Time-consuming, requires strict adherence, depends on the owner’s cooperation |
| Serum IgE/IgG food allergy testing | Claims to identify allergenic foods | Not recommended by ACVD for food allergy diagnosis | Healthy dogs also produce food antibodies, so the false-positive rate is high; results are inconsistent between labs |
| Saliva/hair testing | Claims to identify allergenic foods | Not recognised | Lacks supporting reliable validation studies |
| Intradermal test | Diagnosing environmental allergens | Has clinical value for environmental allergies | No diagnostic value for food allergy; the two must not be confused |
Let’s clear up a common misconception: intradermal testing and serum testing do have clinical uses in diagnosing environmental allergies (dust mites, pollen, mould), mainly to plan desensitisation treatment. The problem is only when the same methods are applied to food allergies. So if a vet suggests allergy testing, it’s worth asking clearly: is this for environmental allergens, or food? The evidence base for the two is completely different.
Tip: the good news is that an elimination diet actually costs less than testing. Take AATU’s 5kg bag: a 10kg dog needs roughly 6-8kg of food over 8-12 weeks, at around HK$600-900 in food costs – and that money buys food that actually goes into your dog’s belly, not a report. The real cost is your discipline – sticking to it strictly for two to three months is the hardest part of an elimination diet.
Step 3: How do you choose the single-protein food for the trial? The key is “never eaten before”
The core logic of an elimination diet is simple: simplify the diet down to just one animal protein, and one the dog has never been exposed to (a novel protein), so you can observe whether the symptoms subside. If the food has three or four meats in it, then even if the symptoms improve, you won’t know which one was ruled out.
According to a systematic review in the veterinary literature (Critically Appraised Topic on Adverse Food Reactions), among confirmed cases of adverse food reactions in dogs, the various allergens appear in the following proportions:
| Allergenic food | Share of confirmed cases | Suitable for the trial period? | Notes |
|---|---|---|---|
| Beef | 34% | Not suitable | The number-one allergen, and also the protein used in the most retail foods |
| Dairy | 17% | Not suitable | Includes cheese-based treats; must be stopped completely during the trial |
| Chicken | 15% | Depends on past diet | Common, but still worth considering if the dog has never eaten chicken |
| Wheat | 13% | Not suitable | Choosing a grain-free recipe avoids it naturally |
| Lamb | 5% | Depends on past diet | Once considered hypoallergenic, but its share has risen as it became more widely used |
Note one key concept: there is no naturally “hypoallergenic” meat, only meat the dog has “never eaten”. Lamb was once the go-to hypoallergenic choice, precisely because very few foods used it back then; once it became a common recipe, allergy cases rose. So the question to ask when choosing a food isn’t “which meat is the most hypoallergenic”, but “what has my dog eaten over the past two years”.
There are four practical rules for choosing a food:
- A single animal protein – the packaging lists only one meat or fish, with no ingredients of unclear origin such as “meat meal” or “animal fat”.
- A protein the dog has never eaten – check the ingredient lists of the foods, cans and treats you’ve fed in the past.
- Grain-free and wheat-free – to also avoid the number-4 allergen.
- Feed only this one food for the entire trial period – no cans, no toppers, no treats.
For relevant products, see BC Pets’ single-protein hypoallergenic dog food category.
Tip: to be honest about one point: a retail single-protein food is not the same as a prescription hydrolysed-protein food. A hydrolysed-protein prescription diet breaks the protein molecules down to a size the immune system struggles to recognise, and is the most rigorous clinical choice; retail foods, because they’re made on shared production lines, theoretically carry a chance of trace cross-contamination. For most mild-to-moderate cases, a retail single-protein food is a reasonable and economical first step; but if there’s no improvement at all after strictly following it for 12 weeks, or the symptoms are severe, you should discuss switching to a prescription hydrolysed food with your vet, rather than continuing to swap between different flavours of retail food.
Step 4: Follow it strictly for 8-12 weeks – one slip and you start the count over
This is the step with the highest failure rate in the whole process. Not because it’s difficult, but because it’s so easy to slip up – a biscuit dropped on the floor, a piece of chicken from a neighbour, a flavoured chew from the vet, are each enough to invalidate the entire trial.
| Timeframe | What to do | What to expect | Common mistakes |
|---|---|---|---|
| Week 0 (preparation) | List every protein you’ve fed in the past; clear all treats out of the house; tell family members and your helper | — | Only telling yourself, while family keep sneaking food |
| Weeks 1-2 | Transition the food gradually over 7-10 days (25% -> 50% -> 75% -> 100%) | There may be brief soft stool, which is a normal reaction to a food change | Completing the switch in one day, causing an upset stomach that’s mistaken for an allergy |
| Weeks 3-6 | Feed the single food only; photograph and record the skin condition and itching frequency each week | Gut symptoms usually improve earlier | Giving up when you see no change – the skin needs more time |
| Weeks 7-8 | Continue, while the vet treats any secondary infections in parallel | Skin symptoms start to improve noticeably | Ignoring ear infections or skin infections, which mask the symptoms |
| Weeks 9-12 | Observe whether the improvement continues and stabilises | About 80% of dogs with a food reaction have clearly improved by this stage | Finishing early, before reaching a sufficient duration |
Things that must be stopped completely during the trial period include, but are not limited to: all treats and training snacks, cans and toppers, human food (including a single small piece), flavoured deworming medicines or supplement chews, dental chews containing meat ingredients, and other dogs’ food (multi-dog households need to feed separately).
If you need training rewards, the only safe approach is to use the kibble of the trial food itself as the treat – just set aside a small portion from the daily amount, which adds no extra calories and introduces no new protein.
Tip: three common “hidden slip-up points” in Hong Kong: one, the estate security guard or a neighbour who “loves the dog” feeds it treats; two, the domestic helper unknowingly mixes human food into the food; three, the flavoured treat handed out at the vet during a vaccination visit. We suggest doing three things: hang a small “On a food trial – please do not feed” tag on the dog’s collar, put away or give away all treats, and proactively tell the vet you’re doing an elimination trial before the visit. These three actions cost nothing, but they can save you two months.
Step 5: Confirm with a rechallenge – skip this step and you’ve only “guessed” the answer
This is the step most people skip, yet it’s the one part of the whole diagnosis that can give you certainty. After the dog’s symptoms improve, the right thing to do is not to celebrate, but to feed the original food again (rechallenge). Only if the symptoms return within a few days to two weeks is it a true confirmed diagnosis of an adverse food reaction; if there’s no problem after going back to the original food, then the improvement may just be a coincidence caused by seasonal changes, a treated secondary infection, or some other factor.
| Stage | What to do | Observation period | Interpreting the result |
|---|---|---|---|
| Rechallenge | Feed the original food again | Up to 2 weeks | Symptoms return = confirmed adverse food reaction; no return = the cause may not be in the food |
| Back to the trial food | Switch back to the single-protein food immediately after symptoms return | 2-4 weeks | Symptoms subside again, giving further confirmation |
| Item-by-item testing (optional) | Add one single ingredient each time and observe for 1-2 weeks | 1-2 weeks each | Identify the specific allergen, widening your choice of foods |
This item-by-item testing step isn’t essential, but it’s very valuable for long-term feeding: if you can confirm your dog only reacts to beef, then the range of foods you can choose from afterwards is far wider, and you’re not stuck forever with the same one. VCA Animal Hospitals’ guide to the elimination-challenge diet trial gives more detailed clinical explanation of this.
Tip: many owners resist the rechallenge, because “the dog is better now, why make it itch again”. This feeling is completely understandable, and a rechallenge should indeed only be done after discussing it with your vet. But what you have to weigh up is this: if you don’t confirm it, you might spend the next dozen-odd years avoiding a food that’s actually fine, while the real cause (such as an environmental allergy) goes unaddressed the whole time. A rechallenge usually only takes a few days to two weeks, so the cost is relatively limited.
Step 6: After confirmation, how to feed for the long term
Once diagnosed, the goal of long-term management is to be “stable but not monotonous”. Here are the practical ways to handle it.
| Situation | Long-term approach | Points to note |
|---|---|---|
| Confirmed allergic to a certain meat | Avoid that protein long-term; other single-protein foods can be rotated | Check the ingredient list before each switch to a new protein, and use a 7-10 day transition |
| Allergic to multiple proteins | Stick with a single-protein food already proven safe | Best to discuss with your vet whether a prescription food is needed |
| No relapse on rechallenge (not a food problem) | Go back to addressing environmental or flea factors | No need to restrict the diet further, but you can keep feeding a quality food |
| Treat choices | Choose single-protein treats with a short ingredient list | The longer the ingredient list, the higher the chance of a hidden allergen |
| Supplements | Choose flavour-free formulas with no meat carrier | Skin supplements such as fish oil are worth considering, but you must confirm the source protein |
For portion sizes, you can use our pet food feeding calculator; for general principles on choosing and storing food, see our complete guide to the AFCD Pet Food Safety Guidelines. For skincare-related products, see skin / coat supplements, and for bathing care, see hypoallergenic bathing products.
Tip: food sensitivity is a lifelong condition, but it doesn’t mean the dog has to eat the same food for life. Once you’ve confirmed a safe protein, you can rotate different brands and recipes within that same protein, or add other single proteins that have been proven safe. The only thing you really need to keep up long-term is one thing: check the ingredient list every time you buy a new product. It’s not unusual for manufacturers to change recipes, and a treat you’ve used for two years may have quietly switched its meat source.
How do you choose a single-protein dog food? Comparing the three big brands: AATU, ACANA Singles and Wellness Simple
BC Pets’ single-protein hypoallergenic dog food section currently has 9 products from 4 brands. The three main ranges have different design philosophies, which directly affects how suitable they are for an elimination trial.
| Brand range | Recipe design | Crude protein | Carbohydrate source | Single proteins available | Pack sizes | Origin |
|---|---|---|---|---|---|---|
| AATU | 80/20 – 80% single meat, 20% fruit, veg and herbs (Superfood Blend) | High | Grain-free, potato-free | Duck, turkey, salmon, chicken | 1.5kg / 5kg / 10kg | Spain / EU |
| ACANA Singles | Limited-ingredient recipe, 50% single meat (including meat, organs, cartilage) + fruit and veg | 31% | Grain-free, around 30% carbohydrate | Duck, lamb | 2kg / 6kg / 11.4kg | Canadian brand |
| Wellness Simple | Limited-ingredient diet (LID) – a single animal protein + a single easily digestible carbohydrate | No less than 25% | Grain-free, uses potato | Salmon | 4.5lb / 10.5lb / 24lb (also available in large / small kibble) | US brand |
You can understand the three approaches like this: AATU takes the high-meat route (80% single meat, no potato), with the shortest ingredient list and the fewest variables; ACANA Singles takes the whole-animal route (meat, organs and cartilage all from the same animal), with high nutrient density; Wellness Simple takes the clinical-reference route, officially positioned as a “natural alternative to common prescription diets”, with a more moderate protein level, suiting dogs with a more sensitive stomach.
Wellness states clearly on its product page: “Dogs with food allergies and food sensitivities should always be under the care of their veterinarian.” – which is in line with the consistent position of this article and worth quoting.
Arranged by protein type: all 9 of BC Pets’ single-protein dog foods
When doing an elimination trial, the real question you should be asking isn’t “which brand is best”, but “which protein has my dog never eaten”. So the list below is arranged by protein type rather than by brand:
| Single protein | Product | Brand range | Reference price (HK$) | Suitability as a trial-period food |
|---|---|---|---|---|
| Duck | AATU Grain-Free Free-Run Duck Adult Dog Food | AATU 80/20 | $238 – $972 | High – duck is relatively uncommon as a main retail food |
| Duck | ACANA Singles Free-Run Duck Adult Dog Food | ACANA Singles | $255 – $860 | High – 50% duck, with duck organs and cartilage, high nutrient density |
| Turkey | AATU Grain-Free Free-Run Turkey Adult Dog Food | AATU 80/20 | $238 – $972 | High – rarely used as a single main protein |
| Lamb | ACANA Singles Grass-Fed Lamb Adult Dog Food | ACANA Singles | $218 – $820 | Medium-high – lamb makes up 5% of confirmed cases, but its use has grown in recent years |
| Salmon | AATU Grain-Free Wild Salmon Adult Dog Food | AATU 80/20 | $238 – $972 | Medium-high – potato-free, the shortest ingredient list |
| Salmon | Wellness Simple Grain-Free Adult Salmon Recipe | Wellness Simple LID | $238 – $847 | Medium-high – 25% protein, contains probiotics, also available in large / small kibble |
| Salmon | RAWZ Grain-Free Single-Protein Wild Salmon Adult Dog Recipe | RAWZ LID | $310 – $1,162 | Medium-high – the highest priced in its category |
| Chicken | AATU Grain-Free Free-Run Chicken Adult Dog Food | AATU 80/20 | $220 – $938 | Low – chicken makes up 15% of confirmed cases, and most dogs have already eaten it |
| Salmon (puppy) | AATU Grain-Free Salmon Puppy Recipe | AATU 85/15 | $242 – $646 | For puppies only – growth-stage nutritional needs differ, so it cannot replace adult food |
5 single-protein choices in total: duck, turkey, lamb, salmon and chicken. Prices range from HK$218 (ACANA Singles Grass-Fed Lamb 2kg) to HK$1,162 (RAWZ Salmon, largest pack).
Tip: always read the ingredient list yourself before buying. “Single protein” is a recipe positioning, and doesn’t mean there are no other animal sources at all in the pack. For example: ACANA Singles’ North American version officially notes “Also contains fish oil” and “Produced in a facility that also processes grains”; the Hong Kong / EU version of the duck recipe uses seaweed as its DHA/EPA source. The same product can have different recipes in different markets, so the only reliable approach is to read the actual ingredient list on the pack in your hand, not the manufacturer’s website or this article. If your dog reacts to fish, this point is especially crucial.
Our brand recommendation: of the three, we suggest starting with duck
First choice: duck – AATU Free-Run Duck ($238-$972) or ACANA Singles Free-Run Duck ($255-$860). The reason isn’t that duck is “more hypoallergenic” – as explained above, there’s no naturally hypoallergenic meat – but that duck is relatively rarely used as a single main protein in Hong Kong’s retail dog foods, so there’s a higher chance your dog has never been exposed to it, which best meets the “novel protein” requirement. And duck happens to be the only protein in the whole range with two brands to choose from: if you want the shortest ingredient list and no potato, pick AATU; if you want high nutrient density with organs and cartilage, pick ACANA Singles. If duck doesn’t work and you need to switch to a second protein, AATU Free-Run Turkey ($238-$972) is the natural next step.
Second choice: salmon – Wellness Simple ($238-$847) or AATU Wild Salmon ($238-$972). Fish protein differs quite a lot in molecular structure from mammals and poultry, making it a common direction for elimination diets. Of the three salmon products, Wellness Simple is best suited to dogs with a more sensitive stomach: its protein is no less than 25% (lower than ACANA’s 31% and AATU’s high-meat recipes), and it adds probiotics and prebiotics, with large / small kibble available for smaller breeds. Wellness also positions this range directly as a “natural alternative to common prescription diets”. The one thing to watch: many dog foods add fish oil as an Omega-3 source, so dogs that have truly “never been exposed to fish” are actually rarer than you’d think – before choosing, be sure to check past ingredient lists for salmon oil or fish oil.
Third choice (depends on the situation): lamb – ACANA Singles Grass-Fed Lamb ($218-$820). This is the cheapest entry-level price in the whole range, with ingredients all from New Zealand grass-fed lamb (including lamb meat, lamb liver, lamb tripe, lamb kidney and lamb cartilage). Lamb makes up only 5% of confirmed cases, which sounds ideal, but note: this low proportion partly reflects “low usage” rather than being “naturally hypoallergenic”, and lamb recipes have become increasingly common in Hong Kong in recent years. If your dog has eaten any food or treat containing lamb in the past, this one isn’t suitable for elimination purposes, but it’s still a quality everyday main food once you’ve confirmed a safe protein.
As for AATU Free-Run Chicken ($220-$938), although it’s one of the best value in the whole range and the same quality 80/20 recipe, we don’t recommend using it for an elimination trial: chicken makes up 15% of confirmed cases and is the most common protein in retail dog foods, so the vast majority of dogs have already had long exposure to it. Using a protein the dog has eaten to run an elimination trial makes the whole trial invalid. A better use for this one is as an everyday main food for dogs already confirmed allergic to beef or another protein but with no reaction to chicken.
Important tip: don’t add AATU cans during the trial period. BC Pets also sells AATU staple wet dog food (400g, $37-$200), with meat content as high as 90% and very good quality – but three of the five varieties are dual-protein recipes (duck & turkey, tuna & salmon, pork & wild boar), and AATU officially labels these as “High protein” rather than “Single source protein”. Within the 8-12 week elimination period, adding any extra protein invalidates the trial. The cans are suitable to introduce only after the trial is complete and a safe protein confirmed, and you should choose the single-protein variety that matches your main food’s protein.
Frequently Asked Questions (FAQ)
Is a blood test for dog food sensitivity accurate? Is it worth doing?
For food allergies, serum IgE/IgG testing is not reliable, and the American College of Veterinary Dermatology does not recommend it. The reason is that a healthy dog producing antibodies to food proteins is itself a normal immune response, so “positive” does not mean allergic; multiple studies have also found these tests have high false-positive rates, inconsistent results between labs, and cannot predict the true allergens an elimination diet reveals. Saliva and hair tests are likewise not recognised. One distinction to note: serum or intradermal testing does have clinical use in diagnosing environmental allergies (dust mites, pollen); the problem is only when applied to food. As of 2026, the elimination diet trial remains the only validated method for diagnosing food sensitivity.
How does a single-protein dog food actually help?
The value of a single-protein food isn’t that it’s “more hypoallergenic”, but that it lets you control the variable. If a food contains chicken, beef and lamb, then even if the dog’s symptoms improve, you can’t tell which one was ruled out; conversely, a food with only duck, combined with a strict 8-12 week trial and a rechallenge, gives you a conclusion you can actually interpret. So when choosing a single-protein food, the most important criterion isn’t price or brand, but whether the dog has eaten this protein in the past – using a protein it has eaten to run an elimination makes the whole trial invalid.
Which meat is most likely to make dogs allergic?
According to systematic reviews in the veterinary literature, among confirmed cases of adverse food reactions in dogs, beef accounts for 34%, dairy 17%, chicken 15%, wheat 13% and lamb 5%. But you need to understand the reason behind these numbers: these are precisely the ingredients most commonly used in retail dog foods, so exposure is high and allergy cases naturally follow. That’s why there’s no naturally “hypoallergenic” meat – lamb was once seen as the go-to hypoallergenic choice, precisely because very few foods used it back then, and its share rose once it became widespread. When choosing a trial-period food, the key question is “what has my dog eaten over the past two years”, not “which meat is the most hypoallergenic”.
How long does an elimination diet take? Can it be shorter?
Veterinary consensus recommends 8 to 12 weeks, and does not advise shortening it. The reason is that gut symptoms usually improve earlier (within a few weeks), but skin symptoms need longer to reflect the dietary change – finishing too early is one of the most common causes of failure in an elimination diet. Throughout the process, any single feeding of another protein (including treats, human food, or flavoured medications or supplements) will invalidate the trial and force you to start over. If you need training rewards, the only safe approach is to use the trial food’s own kibble, set aside from the daily amount.
My dog got better after the trial – do I still need to do a rechallenge?
It’s recommended, and should be done after discussing it with your vet. A rechallenge means feeding the original food again; only if the symptoms return within a few days to two weeks is it a true confirmed diagnosis of an adverse food reaction. If there’s no relapse, it means the earlier improvement may have come from seasonal changes, a treated secondary infection, or other factors, and the real cause still hasn’t been found. The cost of not doing a rechallenge is this: you might spend the next dozen-odd years avoiding a food that’s actually fine, while the real cause (such as an environmental allergy or flea allergy) goes unaddressed the whole time. A rechallenge usually only takes a few days to two weeks.
What’s the difference between AATU, ACANA Singles and Wellness Simple?
All three are single-animal-protein recipes, but with different design approaches. AATU takes the high-meat route (80/20, 80% single meat), grain-free and potato-free, with the shortest ingredient list and fewest variables, in four proteins: duck, turkey, salmon and chicken. ACANA Singles takes the whole-animal route, with 50% single meat including meat, organs and cartilage, 31% crude protein and high nutrient density, in two: duck and lamb. Wellness Simple is a limited-ingredient diet (LID), pairing a single animal protein with a single easily digestible carbohydrate, with crude protein no less than 25%, containing probiotics and prebiotics, officially positioned as a “natural alternative to common prescription diets”, currently in a salmon recipe with large / small kibble available. When doing an elimination trial, the key to your choice isn’t the brand but the protein type – pick one the dog has never eaten.
Which single-protein dog food is best? Where can I buy it in Hong Kong?
BC Pets currently has 9 single-protein hypoallergenic dog foods, covering AATU, ACANA Singles, Wellness Simple and RAWZ, offering 5 single proteins in total – duck, turkey, lamb, salmon and chicken – priced from HK$218 to HK$1,162. For elimination purposes, we suggest prioritising duck (AATU Free-Run Duck $238-$972 or ACANA Singles Free-Run Duck $255-$860), because duck is relatively rarely used as a single main protein in Hong Kong retail foods; salmon or turkey come next. We don’t recommend using chicken for an elimination, as most dogs have had long exposure to it. BC Pets’ shop is at Shop A8, G/F, Flora Plaza, 88 Pak Wo Road, Fanling, New Territories, and we also take online and phone orders, with free delivery on orders over HK$350 – all our stock is authentic Hong Kong retail goods.
What’s the difference between a retail single-protein food and a veterinary prescription hydrolysed food?
A hydrolysed-protein prescription diet breaks the protein molecules down to a size the immune system struggles to recognise, and is the most rigorous diagnostic food clinically; a retail single-protein food is whole protein, and because it’s made on shared production lines, it theoretically carries a chance of trace cross-contamination. For mild-to-moderate cases, a retail single-protein food is a reasonable and economical first step; but if there’s no improvement at all after strictly following it for 12 weeks, or the symptoms are severe (such as widespread hair loss or recurring severe ear infections), you should discuss switching to a prescription hydrolysed food with your vet, rather than constantly swapping between different flavours of retail food.
Will switching food give my dog soft stool? How do I tell an allergy from a food-change reaction?
Yes, and it’s very common. Brief soft stool early in a food change is a normal adjustment reaction, usually settling within 3 to 7 days; an adverse food reaction, on the other hand, is more often persistent and frequently comes with skin symptoms (itching, ear infections, paw-licking). To reduce confusion, always transition food gradually over 7 to 10 days: new food at 25% on days 1-3, 50% on days 4-6, 75% on days 7-9, and a full switch on day 10. If soft stool persists beyond two weeks after this transition, or there’s vomiting, bloody stool or lethargy, you should consult a vet immediately, rather than treating it as an “adjustment period” and continuing to wait and see.
Conclusion: the three core principles of investigating food sensitivity
The whole guide can be boiled down to three sentences:
- Don’t start with a blood test – start by ruling out the other causes. Adverse food reactions account for only 10-25% of allergic skin disease; flea allergy and environmental allergies are more common. First confirm your flea control is in place and observe whether the itching is seasonal – this step costs nothing, but it can save you thousands of dollars and several months.
- The value of a single protein is that it lets you control the variable, not that it’s “hypoallergenic”. When choosing a single-protein dog food, the only question that matters is “what has my dog eaten in the past”. Beef (34%), dairy (17%), chicken (15%) and wheat (13%) are the most common allergens – precisely because they appear most often in retail foods.
- Follow it strictly for 8-12 weeks, and do the rechallenge. Feed one treat midway and you start the count over; if you don’t do a rechallenge after the symptoms improve, you’ve only guessed the answer, not confirmed a diagnosis. There are no shortcuts to these two things, but do them properly and you’ll get an answer you can genuinely use for a lifetime.
Food sensitivity isn’t a terminal illness – it’s just a puzzle that takes patience to solve. And the tool for solving it has been in your dog’s food bowl all along.
Ready to start investigating?
BC Pets has been serving fur-kid families in Hong Kong since 2009, with a shop at Shop A8, G/F, Flora Plaza, 88 Pak Wo Road, Fanling, New Territories, and we also take online and phone orders. All goods sold are guaranteed authentic Hong Kong retail stock, with free delivery across Hong Kong on orders over HK$350, at least 10% off all pet food, plus cash-voucher rebates.
Shop now: all single-protein hypoallergenic dog food (9 products) | AATU grain-free single-protein hypoallergenic dog food | ACANA dog food | Wellness Simple single-protein range | skin / coat supplements.
Not sure which protein to start the trial with? Call 2683-0318 or WhatsApp 5544-7400, tell us the foods and treats your dog has had in the past, and we’ll help you narrow down the protein options it has never been exposed to. But please remember: before formally starting an elimination trial, it’s best to consult your vet first.
Further reading: pet food feeding calculator | complete guide to the AFCD Pet Food Safety Guidelines | buying cat and dog food in Hong Kong: authentic vs grey-import comparison | about BC Pets
Disclosure statement: this article was written by BC Pets (www.bcpets.com.hk). BC Pets is a registered Hong Kong pet supplies and food retailer, operating since 2009, and is the Hong Kong retailer for AATU, ACANA, Wellness and RAWZ products, earning from sales of the products mentioned in this article. To maintain the credibility of our content, our practice is: all medical claims are cited from the Merck Veterinary Manual, the Journal of the American Veterinary Medical Association and peer-reviewed systematic literature reviews, with sources noted; product specifications are cited from the official websites of AATU, ACANA and Wellness. We also state honestly several facts that work against sales, including: a retail single-protein food is not the same as a veterinary prescription hydrolysed food, you should not add AATU cans during the elimination period (as three of them are dual-protein recipes), the cheapest AATU Free-Run Chicken recipe in the whole range is not suitable for elimination purposes, the North American version of ACANA Singles is officially labelled as also containing fish oil and produced in a facility that also processes grains, and lamb’s low allergy proportion partly reflects usage frequency rather than being naturally hypoallergenic. The manufacturers themselves do not make a “hypoallergenic” product claim either – AATU describes it as “single source protein”, ACANA as “Limited Ingredient Diet”, and Wellness clearly states “Dogs with food allergies and food sensitivities should always be under the care of their veterinarian” – and this article follows the same more cautious wording. This article does not constitute veterinary diagnosis or treatment advice.
