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13th May 2020

Has my pet got a food allergy or intolerance?

13th May 2020

Has my pet got a food allergy or intolerance?

13th May 2020

Has my pet got a food allergy or intolerance?

by Laura Crotch-Harvey MSc BSc (Hons)

Does your friendly feline or prized pooch appear to be suffering from allergies or intolerances? Confused by the difference? Let’s outline the differences between pet food allergy and intolerance to help understand your pets’ needs a little more.

Is a food allergy and intolerance the same? The simple answer is no. A pet food allergy involves the immune system and is usually triggered by a response to a protein. A pet food intolerance is an abnormal response to an ingredient but it does not involve the immune system.

The symptoms of both can be very similar. Allergies involve immune reactions and tests are often not reliable so the only true way to determine an adverse food reaction is by feeding an elimination diet. In pets, symptoms of adverse food reactions affecting the digestive system include vomiting and/or diarrhoea, abdominal pain and/or bloating and occasional diarrhoea, flatulence, soft/loose stools. Affecting the skin…itchy skin, inflamed skin and scaly, crusty patches of skin.

An allergy is a damaging immune response by the body to a substance, especially a particular food, pollen, fur, or dust, to which it has become hypersensitive. Hypersensitive; is having extreme physical sensitivity to particular substances or conditions.

An allergy is an abnormal reaction, a disease condition. With seasonal allergy, we cannot avoid contact with the environment but we can change the system, try to restore normal function.  The key to this is the diet. A natural, wholesome diet fed in the right amount can allow the system to regain normal health, whatever the disease condition. For more information read my Veterinary Guide to Natural Healthcare. (John Burns)

As well as diet being a possible cause, if your pet is itching, this may be caused by flea allergy dermatitis (FAD), very common in dogs and cats and caused by a sensitivity to flea saliva – this can be caused by just one or two flea bites.

Owners may not even see fleas on their pet; excessive grooming by hypersensitive pets often removes any evidence. Or it may be caused by environmental allergens like pollen. This type of allergy is known to be inherited. Dogs and cats suffering from an allergy should not be bred from.

If your pet has problems with digestive upset, this may be caused by scavenging, eating too much or fatty food, parasites or infection. Once these things have been ruled out then a food intolerance or allergy should be considered.

Can we avoid adverse food reactions?

In most cases adverse food reactions develop over time, therefore if you have a dog or cat prone to developing reactions you may consider rotating between food varieties to avoid your pet being exposed to the same ingredients over and over. However, if your pet has already had problems and is doing well on one particular variety of food it may be best to continue with this diet. Please speak to one of our nutritionists before changing diets.

Most common food allergies are beef (dogs and cats), dairy (dogs and cats), fish (cat) and wheat (dogs). Dog breeds most commonly affected by food sensitivity include Westies, Cocker Spaniels, Irish Setters, Shar Pei and German Shepherds.

Breeds listed above are just a small proportion more commonly affected by food sensitivity. Areas most affected are the face, paws, lower legs, groin, and, less often, the ears and eyes. In addition to scratching themselves with their hind feet, dogs often lick or chew the affected areas, or rub along the carpet to scratch their face or ears.

Initially, there are no apparent skin abnormalities, except possibly slight reddening, even though the dog is clearly itchy. (This is important because in other conditions there is often a rash or some visible lesion).

Over time lesions develop as a result of the scratching and self-trauma, bacterial or yeast infections, and seborrhea, all of which can contribute to the ‘smelly dog’ odour. The skin becomes reddened and eventually darkened (hyperpigmentation), abraded, thickened, and wrinkled, with loss of hair and bronze staining from saliva.

Gastrointestinal symptoms may include diarrhoea, increased frequency of passing motions, increased stool volume, highly unpleasant smelling stools, vomiting, bad breath, flatulence and inappetence.

Some studies have shown Siamese cats and Siamese crosses are more likely to have skin issues. Similar to dogs, cats will develop itchy skin when an allergy is present. Cats will rarely lick and scratch in front of owners so looking out for other signs is vital.

Furballs or hairs around the tongue, teeth or house will be a good indicator that your cat is over-grooming and licking excessively. Some cats will appear to go bald from over-grooming. Cats can also develop ulcers and moist weeping sores around the head and neck region when a food allergy is present.

Don’t forget treats, supplements, dental chews, rawhide and even some medications all have ingredients that your pet could react to. When trying to avoid certain ingredients in the main diet you will need to look at the composition of these items too.

If you suspect your pet has a food allergy/intolerance…

  • look for a hypoallergenic food as this avoids common allergens like beef or wheat
  • choose a diet with a single protein (meat/fish/egg) source
  • choose a diet with novel ingredients (ones your dog or cat has not eaten before or very often)
  • follow our elimination diet guide

And lastly, contact a friendly Burns nutritionist for advice. Our nutritionists are on-hand every Monday to Friday 9am to 5pm to answer all your pet nutrition enquiries. Reach us on freephone 08000836696, or via email at and LiveChat, if you prefer to communicate digitally.

by Laura Crotch-Harvey MSc BSc (Hons)

I've worked at Burns for over four years and head up a busy, dedicated team of pet nutritionists at our Kidwelly head office. No two days are ever the same. We are often busy going the extra mile for our customers and offer free advice via LiveChat, telephone and email.

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