Cross-reactions between respiratory and food allergens

Cross-reactions between inhaled and food allergens are usually attributed to pollen hypersensitivity associated with fruit and vegetable allergy. However, other allergens are involved in these types of cross-reactions. In a few cases, there is a complete similarity between the inhaled and food allergens (garlic, crustacea proteins). More frequently, partial similarity has been demonstrated: whole inhaled allergens are included in ingested substances. Moreover, immunological techniques can demonstrate common antigenic epitopes in organic substances without any apparent relationship. This has been demonstrated by RAST-inhibition and/or immunoblot techniques, using sera from patients cross-sensitized to (1) pollens and fruits or vegetables or (2) avian sera and eggs. Respiratory sensitization always seems to precede food allergy symptoms.