Food intolerance in dogs

Food intolerance is when a dog’s body is unable to cope with something they’ve eaten and they become ill. This is a common problem and may happen for different reasons. In rare cases, it can be serious, but more commonly, it’s a long-term problem that stops if the problematic food is no longer given.

Food intolerance can happen to any dog, but some types are more common in middle-age dogs. It is different from a food allergy because the immune system isn’t involved. It can be difficult to tell them apart though. Dogs can become intolerant to something they’ve eaten for a long time, but it can also happen the first time they eat something new. Usually the symptoms are a digestive upset, but skin reactions are also common. Diagnosis is usually done with a strict diet for several weeks.

Overview

What is food intolerance in dogs?

There are several causes of food intolerance:

Deficiencies in digesting or using certain foods, such as lactose intolerance in most dogs or gluten sensitivity in Irish setters. In some cases this is genetic.
Metabolic problems that lead to abnormal storage of the components of food in the body. This can lead to problems such as liver disease caused by copper accumulation
Medication-like effects, such as histamine present in fish that is not fresh, cause allergic-type reactions
Abnormal reactions to ingredients in the food
Spoiled foods
When toxic substances are present in the food, such as with grapes and raisins

Most often the end result is that food won’t be digested properly, but other parts of the body may also be affected, with the skin being the most common.

Symptoms

Symptoms of food intolerance in dogs

Food intolerance can have a range of symptoms. Some of the more common ones are:

Vomiting
Diarrhoea
Tummy pain (causing things like abnormal stretching or standing with an arched back)
Loss of appetite
Lack of energy or lethargy
Gas (flatulence)
Red or itchy skin, especially around back end, face, groin and between front legs and body (axilla)
Hair loss
Repeated ear problems and skin infections
Coughing and wheezing may sometimes be seen
In rare cases, there may be symptoms of the nervous system, such as seizures

Risk

Dogs at higher risk of food intolerance

Food intolerance can affect dogs of any age and sometimes develops after a dog has been eating a food for years. It does seem to develop more often when dogs are still young (under 4 years). A few types happen in specific breeds:

Irish setters can have a genetic type of gluten sensitivity
Soft-coated wheaten terriers that develop protein-losing enteropathy may have an underlying food intolerance or allergy

Diagnosis

Diagnosis of food intolerance in dogs

Food intolerance is usually suspected based on the symptoms. Tests may be needed to rule out other diseases:

Faeces tests to rule out intestinal parasites and some infections
Blood tests to rule out diseases of internal organs, such as pancreatitis or liver disease
Skin scrapes to rule out mites

The final diagnosis of food intolerance is usually achieved by doing a strict diet with a special food for 6-8 weeks.

Vet treatment

Vet treatment of food intolerance in dogs

If symptoms are serious, your pet will need to see a vet. Depending on what is found, the vet may recommend:

Intravenous fluids (a drip) to correct dehydration and electrolyte imbalances
Anti-vomiting medication
Antacids to help the stomach heal
Medication to reduce itching, such as antihistamines, Oclacitinib or steroids
Pain medication when necessary
Skin products to soothe the skin and restore the skin’s defences
Some types of infections may be treated with antibiotics

Home treatment

Home treatment of food intolerance in dogs

Avoiding problematic foods is obviously the goal of treating food intolerance. If your dog has managed to eat something they are intolerant of and has developed serious symptoms, speak to a vet (see below). If the symptoms are mild, or once they have improved with treatment at the vet, a few things can be done at home to help with recovery.

If vomiting has been a problem, a short period (4-12 hours, depending on age and other factors) on an empty stomach may help things settle.
Small, frequent meals and an easy to digest diet for a few days will feed the healing of the gut while reducing the symptoms. Chicken/white fish and white rice can help in many cases if your dog is not intolerant to these. Special foods are available to boost the healing of the gut, such as Hill’s I/D and Z/D.
Anti-diarrhoea pastes contain special minerals (for example, kaolin or montmorillonite) that firm up the stool and help reduce the symptoms.
Good bacteria (probiotics) and their food (prebiotics) will help the gut function return to normal.
Skin products are available to help with itchy or irritated skin, but the best product to use will depend on the situation. Speak to a vet for further advice.

Prevention

Can food intolerance in dogs be prevented?

There is no known way to prevent the development of food intolerance. In the case of Irish setters with gluten sensitivity, it’s important to keep them on a diet that manages their symptoms, as otherwise the condition will worsen over time.

When to worry