Shih Tzu itchy ears fixed by diet?

Chronic itchy ears with no infection is a classic sign of a food sensitivity, and Shih Tzus are actually one of the breeds most prone to it — their skin and ears tend to react quickly when something in the diet doesn't agree with them. The vet pointing you toward food is the right instinct. To help narrow things down: what are you currently feeding her, and do you know if she's been eating the same food for a while or has it changed recently? Also, is the itching just the ears, or are you seeing anything on her paws or belly too?

That pattern — ears plus paw licking — is really typical of a dietary sensitivity rather than environmental allergies. Harringtons uses chicken and wheat as main ingredients, and both are common triggers in sensitive dogs. The paw licking especially points to something systemic coming through the skin. Before we go straight to prescription hydrolysed diets, it's worth trying a proper limited-ingredient food with a novel protein — something she hasn't been regularly exposed to. Has she eaten much fish-based food before, or is chicken pretty much what she's always had?

Then fish is a good direction to go. My recommendation would be Royal Canin Sensitivity Control with Duck and Rice — it's a limited-ingredient formula designed exactly for this kind of situation. Duck is a novel protein for most dogs, the rice is easy to digest, and there's no wheat or common allergen fillers. Royal Canin also has strong quality control on cross-contamination, which matters when you're doing a proper elimination-style switch. Give it a solid 8 to 10 weeks on nothing else — no treats with chicken or wheat — before you judge the results. A lot of people give up at four weeks, but skin and ear symptoms can take longer to fully clear. You should start seeing some reduction in the scratching around the 6-week mark if diet is the cause.

Gradually is better — especially since you're trying to use this as a bit of an elimination trial. Mix roughly 25% new food with 75% old for three or four days, then go 50/50, then 75% new, then fully switched over about ten days. That reduces the chance of an upset stomach from the changeover, which could confuse the picture. During the transition and the whole trial period, try to cut out any treats that contain chicken, wheat, or dairy — even small amounts can interfere with what you're trying to figure out. Plain cooked white fish or a small piece of plain rice cake are fine if she needs the odd treat.

If the itching clears up on it, there's no reason you can't feed it long term — it's a nutritionally complete food, not a short-term fix. Some owners do a reintroduction test after a few months (going back to chicken to confirm that's the trigger), but honestly if the dog is comfortable and healthy, many people just stick with what's working. The Sensitivity Control range is designed for ongoing use. If you don't see meaningful improvement after 10 weeks even with strict adherence, that's when it would be worth going back to the vet to talk about hydrolysed protein diets or allergy testing — but most dogs with this kind of presentation do respond well to a proper novel protein switch.