Almost all dogs suffer from an adverse reaction to foodstuff sometime during their lifetime.
In a small number of animals these symptoms persist or return regularly. The cause can be either a food intolerance or a food allergy. Many animal owners show a growing interest in foodstuffs and allergies triggered by them. The veterinary practitioner must be able to meet this demand with sound knowledge and sophisticated diagnostic tools.
 

• What are adverse food reactions?

The term adverse food reaction summarizes all clinical manifestations due to the ingestion of food, regardless of  whether an immune response occurs (food allergy) or not (food intolerance). Often the term intolerance is used incorrectly for an IgG -  mediated  type IV hypersensitivity reaction.
Adverse food reactions can be categorized as follows:
Allergies, pharmacological reactions, idiosyncrasy, toxic reactions and metabolic disorders.
Bacterial overgrowth in the intestine or disturbances of the eating behavior are not considered as ad-verse food reactions.
 

• What is a food allergy?

Food allergy is a hypersensitivity reaction to antigens (allergens) foreign to the bodies immune system. Cause is therefore an immune reaction based on either  IgE - mediated type I hypersensitivity reactions  or IgG - mediated delayed type IV reactions. While immediate allergic reactions are diagnosed quite easily, the delayed response can make the connection between clinical signs and diet quite difficult to establish.
Food allergies are said to be the cause of about 10-15% of all gastrointestinal clinical symptoms.
 

• What are the symptoms?

The symptoms of an allergy to foodstuffs or their components are generally non-specific and appear in a multitude of different illnesses. The food allergy can also occur in combination with other disorders or allergies. Symptoms in cats with food allergies appear as skin disorders such as pruritus, alopezia and dermatitis, generally localized around the head, neck and ears (65%).
 

The most common symptoms are: