Table 1 Current definitions for the terms “allergy”, “sensitization”, “atopy” and “atopic diseases”

Concepts

Allergy is a hypersensitivity reaction initiated by proven or strongly suspected immunologic mechanisms. It can be IgE-mediated or non-IgE mediated. The triggers are substances that the subject has been previously exposed and sensitized.

Sensitization is considered when an underlining immune mechanism is proven by an in vivo or in vitro procedure methods, such as presence of specific IgE or T lymphocyte to an allergen. The sensitization has to be associated to a specific compatible clinical history to lead to the diagnosis of allergy.

Personal and/or familial tendency, usually in childhood or adolescence, to become sensitized and produce IgE antibodies in response to ordinary exposures to allergens, usually proteins.

Development of typical symptoms of asthma, rhinoconjunctivitis, or eczema in atopic patients. These clinical presentations can happen isolated or in combination and, in general, have a different course throughout life.