Allergy and Sensitivity Testing
IgG/IgE Food Sensitivity/Allergy testing
Two of the antibodies involved in allergic reactions are immunoglobulin E (IgE) and immunoglobulin G (IgG). IgE production occurs right after ingestion or inhalation of an allergen and is referred to as a Type I immediate hypersensitivity reaction. IgG antibodies are produced for several hours or days after exposure to an allergen and are called Type III delayed hypersensitivity reactions.
In a Type III delayed hypersensitivity reaction, IgG forms an immune complex with the allergen/antigen (Ag), which activates the complement pathway and releases inflammatory mediators wherever the immune complex is deposited. This process takes anywhere from several hours to several days, which is why hypersensitivity reactions are delayed. Depending on which tissues are involved, deposition of these IgG-Ag complexes may result in the following health concerns:
- Digestive disorders (gas, bloating, cramping, diarrhea, nausea)
- Weight gain
- Mood/Attention disorder (anxiety, depression, irritability, hyperactivity, lack of concentration)
- Joint pain/muscle stiffness
- Skin conditions (itching, redness, swelling, eczema, rashes)
- Lung conditions (Asthma, Bronchitis)
- Loss of memory
- General malaise
IgG allergies are difficult to diagnose because reactions do not occur until hours or days after ingestion of an allergen. This makes it extremely difficult to determine which foods are the causative agents. Blood spot testing for IgG provides a simple and practical means for practitioners to uncover potential causes of allergic reactions and allergy related disease. For detailed information on sample collection, go to the Test Specification Sheet.
Food Sensitivity Reactions
In most cases, no reaction means a food is safe for consumption. However, false negative reactions can occur. In particular, lack of recent exposure to the allergen or non-immune reactions like food intolerances may result in a no reaction even though the patient may be unable to tolerate that specific food.
Some practitioners choose to eliminate low reaction foods from the diet. If there are no moderate or severe reactions to allergens and the patient exhibits allergy-related symptoms, it may be worthwhile eliminating low reaction foods for several months to see if symptoms resolve.
Practitioners may choose to advise patients to eliminate moderately reactive foods from the diet for a period of 3 to 6 months. This enables macrophages time to remove the excess antibody-allergy complexes, which may help alleviate inflammation in various tissues. Patients should be advised that elimination of food allergens often results in withdrawal symptoms like headaches, tiredness, irritability and hunger. Serious cravings for the eliminated foods are also common. After the elimination period is over, it is often possible to reintroduce the eliminated foods without provoking allergic reactions.
It is generally advisable to eliminate highly reactive foods from the diet for a period of 6 months. This allows macrophages time to remove any excess of antibody-allergy complexes, which may help alleviate inflammation in various tissues. Advise patients that elimination of food allergens often results in withdrawal symptoms like headaches, tiredness, irritability and hunger. Serious cravings for the eliminated foods are also common. After the elimination period it may be possible to reintroduce the eliminated foods without provoking allergic reactions.
Rotation diets are available on request. The rotation diet provides a four day diet that excludes the highly reactive foods. This is particularly useful for patients who are highly reactive to a number of foods. Moderately reactive foods are not eliminated in the rotation diet. Practitioners who also wish to eliminate a patient‘s moderately reactive foods will need to modify the supplied rotation diet.↑