How long does it take to get a food allergy out of a dog's system?

Dog food allergies can take anywhere from 2 weeks to 2 months to fully clear up, depending on factors like the severity of the allergy, how long your dog has been exposed to the allergen, and how quickly you remove it from their diet. While some symptoms like vomiting or diarrhoea may improve within days, more persistent issues like itchy skin or ear infections often take longer to resolve. Immediate Reactions Some dogs show improvement in acute symptoms like vomiting or diarrhoea within 24–48 hours of removing the allergen. This is because their digestive system begins to recover quickly once the irritant is gone. Skin Issues Symptoms like itchiness, redness, or rashes can take much longer—typically between 2–4 weeks. Chronic Conditions More severe problems like ear infections, yeast overgrowth, or secondary bacterial infections may take 4–8 weeks to fully resolve, especially if they require antibiotics or other medications. Most dogs will show visible improvement by week 2 or 3. For full recovery, it’s crucial to follow through with the diet until all symptoms are gone. There’s no improvement in symptoms after 4 weeks. Your dog experiences severe symptoms like excessive vomiting, dehydration, or extreme lethargy.

If your dog has a food allergy, their symptoms could take anywhere between six weeks to three months to clear up. However, they will return rapidly if the triggering food is reintroduced. An allergy will usually be lifelong, and so it’s best to avoid the food substance that affects your dog.