Does My Dog Have an Allergy or an Intolerance?

The term allergy is commonly used within the pet nutrition realm.  Whilst allergies to cleaning products or compounds in the environment do occur, the true incidence of food allergy in dogs is quite low.  Whilst allergies do exist, we tend to see a higher number of intolerances, so what’s the difference and do we need to approach them differently?

Let’s take a look at allergies and intolerances in dogs.

What is a food allergy?

A food allergy or other allergic response is caused by an IgE antibody reacting towards that allergen. IgE binds to mast cells to promote histamine release.  In short, the immune system has sensed the particle and wants to get rid of it at all costs.

You’ll know the hallmark signs of an allergy if you are unfortunate to suffer with hay fever, but the common symptoms of an allergy include:

  • Itching
  • Hives
  • Swelling
  • Coughing
  • Sneezing/wheezing
  • Watery eyes
  • Anaphylaxis

What is a food intolerance?

In the case of a food intolerance, we tend to discuss it in terms of IgG.  IgG is the work horse antibody; it is the soldier, the memory antibody. This is what gets drafted when your dog is exposed to something they have already figured out a response to.

Symptoms usually begin within a few hours of eating the food that your dog is intolerant to but it’s important to note that symptoms can be delayed by up to 48 hours and last for hours or even days, making the offending food especially difficult to pinpoint.

IgG’s are mostly raised from the barrier mucosa in the digestive system. After a meal, there are both antibodies and complexes of food antigens bound to specific IgG’s. These complexes are quickly cleared by the reticuloendothelial system.

Clinical observations suggest that due to gut inflammation and permeability (leaky gut), the digestive system is unable to digest the proteins effectively which subsequently raises IgG response to certain foods.

Chronic intestinal inflammations and permeability are related to and possibly responsible for food IgG sensitivity.

A point to note is that 90% of food reactivity comes from IgG’s. Intolerances can be changeable, but allergies tend to be for life and only account for around 10% of food reactivity.

The common signs of an intolerance include, and are not limited to:

  • Poor growth in young pets
  • Itching
  • Vomiting
  • Diarrhoea
  • Flatulence
  • Recurring ear issues
  • Acid reflux
  • SIBO
  • Pain or discomfort
  • Loss of appetite

As you have gathered there is a glitch in immune function in both allergies and intolerances, but we must also consider the function of the digestive system when we are tackling intolerances.

It’s important to note that IgG’s come in different categories but to keep it simple, they are generally defined as cyclic or fixed. A common IgG reaction is cyclic and can take around 3 months to disappear/change. A fixed Intolerance tends to linger for longer and can take around 6 months to disappear/change, what this means is there is no quick fix to support your dog who suffers with intolerances, we’re in it for the long haul.

How to Support the Intolerant Dog

First of all, we prime and reset the digestive system, and this includes starting with an elimination diet, but also includes gut healing and immune balancing protocols.

We follow the 4 R’s. 

Remove – carry out an elimination diet.

Raw or lightly cooked is the best way to do this. Cooked foods can take pressure off the digestive system, which in these cases is beneficial.

Start with novel proteins (proteins your dog’s immune system has not seen before) for example, horse, ostrich, kangaroo and hare are generally well tolerated. Horse is lean too, so a great option if digestive function isn’t where it needs to be, yet.

Feed this novel protein for 4-12 weeks. Ideally if you land on a novel protein that helps the itch/digestive discomfort or doesn’t make it any worse, we recommend remaining on this protein for 12 weeks.  As we noted this is the time it takes for an intolerance to change.

We then introduce other novel proteins – but at no more than one per week and sticking to single source. Treats need to match too!

If there are signs of intolerance, then remove that protein and go back to a protein you believe is best tolerated.

Notice that it’s called an elimination diet, and not an elimination lifestyle. The overall aim is to eventually maintain a strong diversity in the diet as we know this supports optimal gut health. We would be looking to reintroduce more common proteins as time went on – but this takes time. We also practice the same process when reintroducing any fruit or vegetables – one at a time, over time. It can also be worthwhile opting for a low-histamine approach when reintroducing too.

Repair – support immunity and gut healing.

Include ingredients like slippery elm, de-glycerised liquorice, glutamine, and N-acetyl-glucosamine. It is also important to consider how existing medications are affecting gut healing for example, steroid use impairs intestinal absorption which is linked to several gastrointestinal dysfunctions. But, because of their anti-inflammatory and immunosuppressive activities, they are often prescribed in cases of allergies or intolerance.

Findings here

Restore – optimise microbiome health

As the microbiome is key in the development of the immune system, supporting this is essential.  However, the introduction of specific pre and probiotic foods or supplements is sometimes best left for a few weeks into your plan, especially when carrying out an elimination diet.  There may be probiotics on the market that contain protein sources not indicated on the label – always check with the manufacturer what is contained in their product and indicate that you are carrying out an elimination diet, so you need accurate information.


Indigestibility of food proteins can also contribute to their antigenic nature, so consider any long-term medication use including proton pump inhibitors which affect gastric acid secretion. Ensuring HCL, pepsin and digestive enzymes are in good supply will help get the digestive system back to doing what it does best!  Moving forwards, think about the dog’s digestive system from the mouth down.  What is going on at each stage and are these processes optimised?  Is there anything that could compromise their function? This includes stress.

To learn more about the digestive system in the dog, check out our blog here:

The Dog’s Digestive System

Can Stress Affect My Dog’s Digestive System?

Sadly, intolerances are quite common in dogs, so if you would like some support with your pet, then check out our services to see how we can help.

Thanks for reading,
MPN Team

Keep up to date

Subscribe to our newsletter for recipes, DIY products, health solutions and more.

You have been successfully Subscribed! Ops! Something went wrong, please try again.

Customer Reviews

Related articles