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Idiosyncratic Illnesses
Idiosyncratic illnesses are adverse reactions to foods that occur through an unknown mechanism(s) resulting in a wide range of symptoms ranging from mild skin irritation to life-threatening reactions.
A few idiosyncratic reactions are well defined and the causative food or ingredient implicated in the reactions has been identified.
- Sulfite-induced asthma is an example of a well defined idiosyncratic reaction where clinical evidence has shown that sulfite is the causative agent in the asthmatic reactions.
The exact mechanism that triggers the reaction remains unclear. Other idiosyncratic reactions that have not been well defined include:
- tartrazine-induced asthma;
- MSG-induced asthma;
- chronic urticaria from exposure to BHT, BHA, or tartrazine;
- migraine headaches from chocolate and aspartame.
The prevalence of food-induced idiosyncratic reactions remains unknown as it is difficult to determine the relationship between the adverse reaction and the specific food or ingredient involved.
The use of double-blind, placebo-controlled food challenges (DBPCFC) is the best way to establish whether or not a food or ingredient implicated in the reaction is actually the causative agent. These DBPCFC must be conducted in a clinical setting and can often be quite expensive to conduct so they are not widely used to identify foods implicated in a majority of idiosyncratic reactions.