Shih Tzu itchy face and paws in multi-pet home

Skin allergies are honestly one of the most exhausting things to deal with as a dog owner — they're chronic, they're hard to pin down, and they almost always need a multi-pronged approach. The critical first fork in the road is working out whether the trigger is environmental or food-related, and in your case there's a really specific wrinkle worth exploring straight away: your Shih Tzu is sharing a food area with two cats, which means she may well be snacking on cat food — and cat food is notoriously high in proteins that can drive allergic reactions in dogs. Before we go further, can you tell me: what symptoms are you seeing exactly — is it constant or does it flare up at certain times — and has she been seen by a vet yet?

Year-round symptoms with face and paw involvement is a classic pattern for food allergy rather than environmental — grass pollen and dust mites tend to cause more generalised itching and often have a seasonal spike. The paw chewing in particular is a strong food-allergy signal in Shih Tzus. Now, the cat food situation matters a lot here. Do you know whether she's actually eating the cats' food, or just nearby when they eat? And what is she currently being fed day-to-day?

That's really useful — and honestly that combination is a very plausible explanation. Supermarket own-brand kibbles often contain multiple protein sources and fillers that aren't always clearly labelled, and cat food tends to be extremely high in animal protein and fat. If she's getting both regularly, her system could be reacting to any number of ingredients and you'd have no way of knowing which. The gold standard next step is a proper elimination diet — you feed a single novel protein source she's never had before for 8–10 weeks, with absolutely nothing else, to see if symptoms resolve. For that I'd recommend Royal Canin Sensitivity Control (duck and tapioca) — it's a single novel protein hydrolysed diet, widely available on Amazon UK, and it's one of the most reliable starting points for a food elimination trial in small breeds. Duck is something most dogs haven't eaten before, and tapioca replaces common grain allergens. Crucially, during the trial the cat food access has to stop completely — even small amounts will invalidate the results.

You should start seeing meaningful improvement within 4–6 weeks if food is the primary driver, though the full 8–10 week trial is needed before you can be confident. Some dogs show a reduction in paw chewing within 3 weeks; facial itching can take slightly longer to settle. If there's no improvement at all by week six, that points more towards an environmental cause — dust mites are the most common culprit in year-round cases — and that's when a vet referral for allergy testing becomes the logical next step. Either way, I'd book a vet appointment now to run it alongside the diet trial. They can also rule out a secondary skin infection, which is common when dogs have been itching for a while.

Good plan — separating the feeding areas is genuinely half the battle in multi-pet homes. Feed the cats somewhere the Shih Tzu can't access, pick up any leftover cat food straight after meals, and keep a simple diary of her symptoms week by week so you have something concrete to show the vet. The Royal Canin Sensitivity Control in the duck and tapioca variant is the one to go for — it comes in both wet and dry forms, but the dry is easiest for a consistent elimination trial. Good luck with her; year-round itching is miserable for the dog and stressful for owners, but a methodical approach like this usually gets to the bottom of it.