Food Testing
Adverse reactions to food may initiate a myriad of physiological effects in the body.
These reactions can affect the immune system in different ways and can result in signs and symptoms ranging in severity from mild to life threatening anaphylaxis.
Although the majority of severe allergic reactions are thought to be mediated via an IgE reaction, other immune globulins, such as IgG and IgA, may play a role in adverse reactions to food as well, presenting as food sensitivities rather than allergy.
These reactions can affect the immune system in different ways and can result in signs and symptoms ranging in severity from mild to life threatening anaphylaxis.
Although the majority of severe allergic reactions are thought to be mediated via an IgE reaction, other immune globulins, such as IgG and IgA, may play a role in adverse reactions to food as well, presenting as food sensitivities rather than allergy.
IgE-mediated food reactions are immediate in onset and usually involve symptoms such as abdominal cramping, diarrhoea, skin rashes, hives, swelling, wheezing or the most extreme reaction, anaphylaxis.
IgG-mediated food reactions (also referred to as food sensitivity, food intolerance) are more subtle in their presentation, often occurring hours to days after exposure to food antigens.
Delayed food reactions may affect any organ or tissue in the body.
Common conditions where food sensitivity may play a significant role include abdominal bloating and fluid retention, inflammatory bowel disease, irritable bowel syndrome, migraine, depression, mood swings, asthma, skin conditions, and behavioural problems in children.
It has been found that an increased IgG antibody level to foods, especially to egg white, orange, and a mixture of wheat and rice, is a positive predictor of increased IgE antibodies to inhalant allergens such as dust mite, cat and dog hair.
Early testing for IgG food sensitivity in children may therefore identify children with an increased risk of developing future allergic disease
- When provoked by a recognised food antigen, IgE antibodies promote mast cell degranulation and the release of histamine and other inflammatory mediators bringing about the strong response.
IgG-mediated food reactions (also referred to as food sensitivity, food intolerance) are more subtle in their presentation, often occurring hours to days after exposure to food antigens.
- Unlike IgE-mediated food reactions, IgG-mediated food reactions produce symptoms which are cumulative in nature.
- Instead of attaching to mast cells, like the IgE antibodies, IgG antibodies bind directly to food as it enters the bloodstream forming circulating immune complexes
Delayed food reactions may affect any organ or tissue in the body.
Common conditions where food sensitivity may play a significant role include abdominal bloating and fluid retention, inflammatory bowel disease, irritable bowel syndrome, migraine, depression, mood swings, asthma, skin conditions, and behavioural problems in children.
It has been found that an increased IgG antibody level to foods, especially to egg white, orange, and a mixture of wheat and rice, is a positive predictor of increased IgE antibodies to inhalant allergens such as dust mite, cat and dog hair.
Early testing for IgG food sensitivity in children may therefore identify children with an increased risk of developing future allergic disease
