Allergies to fruits and vegetables.

Allergic reactions to fruits and vegetables are frequently observed in older children and adolescents. They can result from a primary sensitization to food allergens or from a primary sensitization to inhalant allergens such as pollens or latex. In the case of fruit allergies, the stability of the allergens involved is crucial to the sensitization pathway and in the clinical presentation of the food allergy. Two patients allergic to fruits are presented and discussed in the light of the allergens involved. Patient 1 was a 14 yr-old girl with a grass and olive pollen allergy who developed oropharyngeal symptoms typical of the oral allergy syndrome (OAS) with multiple fruits from taxonomically unrelated families, and who was sensitized to profilin. Patient 2 was an 8 yr-old girl, with no pollen allergies, who developed systemic reactions to peach and apple, and who was sensitized to non-specific lipid transfer proteins (LTP). Profilins are labile allergens present in pollens and foods, and sensitization occurs through the respiratory route to pollen profilin. The cross-reactive IgE antibodies generated can elicit local reactions in the oropharyngeal mucosa (OAS) when exposed to fruit profilins. In contrast, LTPs are a family of stable allergens that resist thermal treatment and enzymatic digestion, and can thus behave as true food allergens inducing primary (non-pollen related) sensitizations and triggering systemic reactions. These two cases represent two distinct patterns of sensitization and clinical expression of fruit allergies that are determined by the panallergens involved (LTPs and profilins) and their intrinsic physicochemical properties. Additionally, these two cases also show the improved diagnostic value of Component Resolved Diagnosis, and strengthen its utility in the routine diagnosis and management of patients.