More and more dogs are presenting adverse reactions to certain foods. Behind persistent itching, chronic diarrhoea or a dull coat, there may be a food allergy or intolerance that goes unnoticed for months.
Identifying the problem in time and adapting the diet is key to improving the dog's quality of life. In this guide we explain the difference between allergy and intolerance, how to recognise the symptoms and what type of diet helps to manage it.
Allergy or intolerance? They are not the same thing
Food allergy
This involves a response from the immune system. The body mistakenly identifies a specific protein as a threat and generates an immune reaction. Symptoms can be immediate or delayed, and tend to be more severe. Food allergies are less common than is generally believed.
Food intolerance
This does not involve the immune system. It is an inability of the digestive system to process certain ingredients correctly. Symptoms are mainly digestive and tend to appear gradually. Intolerances are more common.
What are the most common allergens in dogs?
Proteins are the most common allergens. The most frequent in dogs are:
- Beef (the most documented)
- Chicken
- Dairy products
- Wheat and gluten
- Soya
- Egg
- Pork
- Lamb (in cases of prior exposure)
It is important to understand that a dog develops an allergy to ingredients they have already consumed before, not to new proteins. The immune system requires prior exposure in order to become sensitised.
Symptoms of food allergy or intolerance
Signs can vary greatly from one dog to another. The most common are:
Skin symptoms
- Generalised or localised itching (paws, ears, abdomen, armpits)
- Skin redness
- Recurrent ear infections
- Hair loss
- Rashes or papules
Digestive symptoms
- Chronic or intermittent diarrhoea
- Frequent vomiting
- Excessive flatulence
- Soft, foul-smelling stools
Other signs
- Poor overall coat condition
- Conjunctivitis or recurrent eye discharge
- Behavioural changes due to ongoing discomfort
An important note: food allergies do not have a seasonal presentation. If your dog itches all year round, including during winter months, it is more likely to be a food allergy than an environmental problem.
How is it diagnosed?
There is no reliable blood test to diagnose food allergies in dogs. The most effective method is the elimination diet:
- All habitual ingredients are removed from the diet.
- A novel protein source (one the dog has never tried) and a simple carbohydrate are introduced for 8-12 weeks.
- If symptoms improve, ingredients are reintroduced one by one to identify which one triggers the reaction.
This process requires total discipline: no treats, snacks or leftovers during the elimination period. A single bite of the problematic ingredient can invalidate weeks of testing.
Appropriate diet for dogs with allergies or intolerances
Mono-protein diets
Mono-protein diets use a single source of animal protein, which makes it easier to identify and manage the allergen. They are the basis of both diagnosis and long-term management.
Hydrolysed proteins
Hydrolysed proteins are protein molecules that have been broken down into fragments so small that the immune system does not recognise them as threats. They are useful in severe cases or when there is no response to a conventional elimination diet.
Novel proteins
Protein sources the dog has not consumed before: kangaroo, bison, venison, insect, duck, wild boar. With no prior exposure, sensitisation is unlikely.
Grain-free or gluten-free
For dogs with wheat or gluten intolerance, grain-free recipes or those with gluten-free carbohydrate sources (sweet potato, pea, rice) can significantly improve digestive wellbeing.
How long does it take to improve?
Improvement in skin symptoms can take between 4 and 8 weeks after removing the allergen. Digestive symptoms tend to resolve sooner, sometimes within a few days. Patience is essential.
Nutrition designed for sensitive skin
At OnlyFresh you will find brands such as Amanova, Harper and Bone and TrovetPlus with specific recipes for dogs with food sensitivities: mono-protein, without colourings, without unnecessary additives, made with high-quality ingredients. If your dog has chronic skin or digestive problems, speaking to your vet and reviewing their diet is always the first step.
