Best Dog Food for Shih Tzus With Allergies (2026): What Vets Recommend
Disclosure: This guide contains affiliate links. As an Amazon Associate, Shih Tzu Pedia earns from qualifying purchases on Amazon.com and Amazon.ca, at no extra cost to you. Our picks are based on veterinary guidance and published product details, not on hands-on testing.
How we chose these foods: We used guidance from VCA Animal Hospitals and peer-reviewed research on food allergies in dogs, including a 2016 review in BMC Veterinary Research and a 2019 study in Veterinary Medicine and Science. We then compared current Amazon listings for diet type, small-breed options, ratings, and availability in the United States and Canada. Last reviewed: September 2026.
Is your Shih Tzu always scratching, licking its paws, or fighting ear infections? Food allergy is one possible cause. But it is not the only one. Fleas and environmental allergies can cause the same signs.
This matters because no store-bought food can diagnose a food allergy. The only reliable test is a strict diet trial guided by your vet. This guide explains how that works, which foods vets use, and which over-the-counter foods may help a dog with milder skin sensitivity.
Quick Picks: Best Food for a Shih Tzu With Allergies
| Pick | Best for | Type | Shop |
|---|---|---|---|
| Hill’s Prescription Diet z/d | Diagnosed or suspected food allergy (vet use) | Hydrolyzed, prescription | Amazon.com | Amazon.ca |
| Royal Canin Small Sensitive Skin Care | Dry, sensitive skin (non-prescription) | Dry | Amazon.com |
| Purina Pro Plan Sensitive Skin & Stomach Small Breed (Salmon) | Skin plus stomach support | Dry | Amazon.com | Amazon.ca |
| Natural Balance Limited Ingredient Small Breed Lamb & Brown Rice | Simple recipe with one animal protein | Dry | Amazon.com |
Signs of a Food Allergy in Shih Tzus
VCA Animal Hospitals lists these common signs of food allergy in dogs:
- Itchy skin, especially on the paws and ears
- Repeated ear infections
- Vomiting or diarrhea
- Less often, weight loss, low energy, or behavior changes
Many of these signs overlap with other skin problems. Read our guide to itchy skin in Shih Tzus to understand the other causes, and see your vet before you change foods.
What Are Dogs Most Often Allergic To?
A 2016 review in BMC Veterinary Research pooled data on 297 dogs with food allergies confirmed by diet trials. The most commonly reported triggers were:
| Food | Share of dogs reacting |
|---|---|
| Beef | 34% |
| Dairy | 17% |
| Chicken | 15% |
| Wheat | 13% |
| Lamb | 5% |
Wheat is on the list, but the top three triggers are animal proteins. A grain-free food is not an allergy treatment by itself.
How Vets Diagnose a Food Allergy
VCA Animal Hospitals says the most reliable method is an elimination diet trial. Here is how it works:
- Your vet chooses a hypoallergenic diet. This is usually a hydrolyzed protein diet, where proteins are broken into pieces too small for the immune system to recognize, or a novel protein diet made from ingredients your dog has never eaten.
- Your dog eats only that food for 8 to 12 weeks. No treats, table scraps, flavored medicines, or other foods.
- If the signs improve, your vet may have you reintroduce the old food. If signs return, usually within about a week, a food allergy is likely.
Why store-bought “limited ingredient” foods are not enough for a diet trial: VCA notes that retail limited-ingredient foods are not made with the strict protocols used for prescription diets to prevent cross-contamination. A 2019 study tested 21 over-the-counter dog foods with uncommon or limited ingredients. All 21 contained mammal DNA that was not listed on the label. The authors concluded these foods cannot be relied on to diagnose or manage food allergies.
The Best Foods for a Shih Tzu With Allergies, Reviewed
1. Hill’s Prescription Diet z/d
Best for: Dogs doing a vet-guided elimination trial, or dogs already diagnosed with a food allergy.
- Made with highly hydrolyzed proteins broken down to avoid detection by the immune system, according to Hill’s
- Omega-3 and omega-6 fatty acids for skin health
- Available as a Small Bites kibble. Check the bag size and kibble option on the listing before you buy.
Why we picked it: A hydrolyzed diet is one of the options VCA describes for diagnosing and managing food allergies. The Small Bites option suits a Shih Tzu.
Keep in mind: This is a prescription diet. Use it only under your vet’s direction. Some sellers may ask for vet approval before shipping. Your vet may also prefer a different therapeutic diet.
Check price on Amazon.com → | Check price on Amazon.ca →
2. Royal Canin Small Sensitive Skin Care
Best for: Small dogs with dry or sensitive skin that do not have a diagnosed food allergy.
- Made for small dogs 10 months and older, according to the brand
- Omega-3 and omega-6 fatty acids for dry skin and coat
Why we picked it: It targets skin and coat health in a small-breed kibble.
Keep in mind: It is not a hypoallergenic diet and is not suitable for a diet trial. It was not in stock on Amazon.ca when we checked.
3. Purina Pro Plan Sensitive Skin & Stomach, Small Breed (Salmon)
Best for: Dogs with both skin and stomach sensitivity.
- Real salmon is the first ingredient
- Guaranteed live probiotics, per the listing
- Made for small breed dogs
Why we picked it: Salmon is not among the most common allergy triggers in the 2016 review, and this formula supports both skin and digestion.
Keep in mind: It is not a hypoallergenic diet. If your dog must avoid a specific protein, read the full ingredient list on the bag before buying.
Check price on Amazon.com → | Check price on Amazon.ca →
4. Natural Balance Limited Ingredient, Small Breed, Lamb & Brown Rice
Best for: Owners who want a simple recipe with a single animal protein.
- Lamb is the single animal protein source, according to the brand
- Brown rice as the main grain
- Omega-3 and omega-6 fatty acid sources for skin and coat
Why we picked it: A shorter ingredient list makes it easier to avoid common triggers such as beef, dairy, and chicken.
Keep in mind: As the 2019 study showed, over-the-counter limited-ingredient foods can contain proteins not listed on the label. Do not use this food for a diet trial. It was not in stock on Amazon.ca when we checked.
Tips for Feeding a Shih Tzu With Allergies
- Check every treat. Treats, dental chews, and flavored medicines can break a diet trial. Ask your vet which treats are safe. Our treat guide has more on choosing treats.
- Switch foods slowly. Mix the new food in gradually over about 10 days to avoid stomach upset. Our sensitive stomach guide has a sample schedule.
- Keep a symptom diary. Write down itching, ear problems, and stool changes each week. It helps your vet judge whether the diet is working.
- Be patient. VCA notes a diet trial takes 8 to 12 weeks. Skin needs time to heal.
Frequently Asked Questions
What is the best dog food for a Shih Tzu with allergies?
For a diagnosed or suspected food allergy, vets usually recommend a prescription hydrolyzed or novel protein diet, such as Hill’s Prescription Diet z/d. For mild skin sensitivity without a food allergy, a skin-support food such as Royal Canin Small Sensitive Skin Care or Purina Pro Plan Sensitive Skin & Stomach may help. Ask your vet which fits your dog.
What foods are Shih Tzus most often allergic to?
There is no evidence that Shih Tzus differ from other dogs here. In a 2016 review of 297 dogs with food allergies, the most common triggers were beef (34%), dairy (17%), chicken (15%), and wheat (13%).
How long does it take for a new diet to help allergies?
VCA Animal Hospitals says an elimination diet trial should last 8 to 12 weeks. Skin changes take time, so do not judge a new food after only a week or two.
Is grain-free food good for a Shih Tzu with allergies?
Not usually. Wheat is one possible trigger, but proteins such as beef, dairy, and chicken are reported more often. Some grain-free foods are also high in peas and lentils, which veterinary researchers are studying for a possible link to heart disease. Ask your vet before choosing grain-free.
Can I do a food trial with a limited ingredient food from the pet store?
It is not recommended. A 2019 study found undeclared mammal DNA in all 21 over-the-counter limited-ingredient foods it tested. VCA also notes these foods are not made with the same controls as prescription diets. Use a diet your vet recommends.
Sources
- VCA Animal Hospitals: Food allergies in dogs
- Mueller RS, Olivry T, Prélaud P. Common food allergen sources in dogs and cats. BMC Veterinary Research, 2016
- Fossati LA, et al. Determination of mammalian DNA in commercial canine diets with uncommon and limited ingredients. Veterinary Medicine and Science, 2019
- Tufts Petfoodology: Update on diet-associated dilated cardiomyopathy, June 2026
- Amazon.com and Amazon.ca product listings, checked September 2026
This article is for general information. It is not a substitute for advice from your veterinarian. Read our medical disclaimer.
