Learn more about food allergies in dogs
Just like us, dogs can develop food allergies or food intolerance at any time of their life, even after years of eating the same food!
If your dog has a food allergy their immune system mistakenly sees a certain part of the food (allergen) as a threat to the body. Their body reacts by producing antibodies to the allergen in a similar way to the response to bacteria or viruses. The resulting immune response can impact the whole body.
Dogs are most often allergic to proteins in the diet. The most common allergens identified as triggers in dogs with food allergies are: beef | dairy | chicken | wheat | lamb
There may be a genetic component to food intolerances in dogs. However, the exact mechanism of why allergies/intolerance develop in some dogs and not in others is not fully understood.
Dogs can have allergies from an early age, or they can develop them several years into life.
Written by Dr. Mariella Roberts, Veterinary Surgeon, Animal Trust Vets CIC | Published April 2025 | Review date April 2027 | This advice is for UK pets only and is not a replacement for seeing a vet
Signs
Signs of a food allergy or intolerance can include:
Vomiting
An upset stomach (diarrhoea)
Excessive wind (flatulence)
Losing weight
Increased appetite
Itchy skin that can become red and irritated
Regularly skin or ear infections
Grooming excessively
When to contact your vet
Contact us if you think your dog may have a food allergy or have any symptoms above. There are several other health problems that could cause similar effects, so it’s important that you speak to your vet to determine what is wrong with your dog.
Diagnosis
The best and most accurate method of diagnosing a food allergy is to feed a hypoallergenic dog food / diet for 8 to 12 weeks as a food trial, called an elimination trial or exclusion diet. To be a true elimination trial, this special diet must not contain any ingredients that your dog has eaten in the past. It also requires that no other foods, treats, or supplements are fed during the trial period. If your dog’s symptoms get better during the trial, it suggests that they were reacting to something in their food. If your dog is on a prescription diet, or supplements for an existing condition, please discuss this with your vet prior to considering an elimination trial.
Once the offending food substance has been identified, a longer-term diet that does not include the allergen can be chosen.
There are three general types of hypoallergenic diets that could be considered for an elimination trial:
Veterinary hydrolysed protein diet, in which the protein molecules are broken down to a size too small to be recognised by your dog’s immune system. These are nutritionally complete and available as dry food, for convenience (wet foods may also be available).
Veterinary novel protein diet that does not contain any products that were present in your dog’s previous foods. These are also nutritionally complete diets and available as dry food (wet food versions may be available).
Home-prepared novel protein diet that does not contain any ingredients that were present in your dog’s previous diets (these must be formulated by a veterinary nutritionist and may require the addition of balancing supplements).
It is important to be aware that simply changing the flavour of your dog's food does not constitute an elimination diet. This is because food manufacturers only have to display the main components of the food, in respect to the flavour, and this may mean that other proteins are also present. These are not harmful to your pet, but if they are allergic to them then the allergic reaction will persist, despite change of food. For this reason, commercial dog foods are not usually considered the best choice for use in an elimination trial.
Dog Food Allergy Treatment
Because it can take 8 to 12 weeks before itching associated with food allergies improves, your veterinarian may recommend anti-itch treatments to help keep your pet comfortable while we work to decide if your pet has a food allergy. Medications commonly used for the treatment of itch associated with allergies include:
Lokivetmab (Cytopoint - a monthly injection)
Oclacitinib (Apoquel – daily tablets)
Ciclosporin (Daily tablets)
Steroid tablets (these are not usually recommended for long term use, due to side effects which can develop if used over an extended period)
Antihistamines (these are often relatively ineffective in dogs, but may have a role to play in management)
In addition, some pets may develop skin infections because of food allergies. Infections may be treated with any of the following: antibiotics, antifungal, topicals treatments such as shampoo, spray and ear medications and cleaner.
Food supplements may also be helpful in some cases, providing they do not contain ingredients which may contribute to the allergic response. Please discuss any use of supplements with your vet prior to trying any of these products.
Prevention
Food allergies cannot be cured, but they can be well-managed long term with appropriate diet therapy and avoidance of offending ingredients, plus medications to reduce symptoms, if and when they arise.
Outlook
The outlook/prognosis for food allergy is usually very good if a dietary trial can be performed strictly and for the correct period. If the offending food items can be identified and eliminated from the diet, many patients do not need further treatment.