When allergies complicate allergies.

The 'allergic march' is a term used to describe an individual's progress from one clinical manifestation of allergy to another, with age. Not all sensitized children will join the allergic march, but it appears that individuals who do not join the allergic march have a greater risk of displaying symptoms of allergic disease in adulthood. Consequently, there is a need for early diagnosis of allergy in children. Immunoglobulin E (IgE) antibody quantification is increasingly used for this purpose. However, rather than making a diagnosis based on single positive IgE antibody results only, it may be more efficient to test a profile of airborne and food allergens and use the sum of IgE antibody concentrations > or =3.5 kUA/l in combination with the number of allergens that elicit positive results tests. Allergic diseases often co-exist in patients, and the combination of several exposures at a given time (the allergen load) is related to disease severity. Therefore, a reduction of the allergen load is a key to successful treatment.