Is it allergy or non-allergic hypersensitivity?
Hypersensitivity reactions can be broadly divided into allergic (immune system mediated) and non-allergic (immune system not involved). Table 1 shows the division of the two types of hypersensitive reactions but they are not exclusive since some individuals may have both types of hypersensitive reactions occurring at the same time. Nonallergic hypersensitivity probably accounts for the majority of the adverse food reactions clinically seen in adults. Over the years many individuals have reported adverse reactions to certain foods additives including aspartame (an artificial sweetener), monosodium glutamate (a flavour enhancer), nitrates/nitrites (preservatives), sulpher-based compounds (preservatives) and a wide range of other compounds. Table 2 shows the nature of symptoms associated with immune-mediated allergy and non-immune mediated hypersensitivity. Currently there is no in vitro test that can detect non-immune allergic hypersensitivity disorders. The only way these food hypersensitivity problems can be detected is through oral challenge tests of foods and chemicals done in the clinic.

Allergic diseases are increasing at a fast rate throughout the world. The increase in allergic disease is primarily due to the increase of IgE-mediated allergies. Other types of allergies (e.g. contact allergy) have not shown any major increase in the last 50 years. The triggers for IgE-mediated allergies can be easily identified through blood tests (see blood allergy tests below).

 

 

Table 1: Nature of food hypersensitivity reactions. Food hypersensitivity can be broadly divided into immune-mediated food allergy and non-allergic food hypersensitivity where the immune system is not involved.

 

 

 

Table 2: Nature of symptoms with immune (allergy) and non-immune hypersensitivity reactions (intolerance)