ALLERGY - FOOD
 
Definition

A food allergy occurs when the body's immune system responds to otherwise benign proteins (allergens) as though they were threats to the health and integrity of the system. In a classic reaction, the immune system produces IgE antibodies. When these antibodies react with the allergen, histamine and other chemicals (mediators) are released. This process then gives rise to such allergic symptoms as itching, swelling, hives, and breathing difficulties. While most food allergies are mild, in some cases they can cause anaphylactic shock. Because this type of reaction can be life-threatening, food allergies must be taken seriously.

The majority of adverse reactions to food are caused by non-immunologic mediated mechanisms. Also called food intolerance or food hypersensitivity, adverse food reactions can occur because a person lacks the enzymes needed for proper digestion, such as those for the lactose in milk, or because they have a sensitivity to such common preservatives and additives as monosodium glutamate (MSG), sulphites and gluten. Some adverse reactions are caused by food-borne microbial pathogens and toxins.
 

Aetiology / Risk Factors

Major causative factors and risk factors that can contribute to the incidence of allergies include the following:

  • Foods that most commonly cause allergic reactions include peanuts, tree nuts, milk, eggs, soy, fish, shellfish, wheat, some fruits, seeds, and chocolate. Food allergies arise when a genetic sensitivity is coupled with environmental exposure.
  • Family history of allergies, asthma, or atopic dermatitis
  • Personal history of asthma, atopic dermatitis, or other allergies
  • Poor digestive acid secretion
 
Symptoms and Signs
 
Common signs and symptoms of food allergies include: