Figure 1.

Sensitization to class I and class II nut allergens is associated with different clinical symptoms. Sensitization to class II nut allergens usually occurs by respiratory sensitization to cross-reactive respiratory allergens (e.g., pollen allergens) and is associated with mild symptoms such as oral allergy syndrome, local reactions in the oropharynx, esophagus and may trigger atopic dermatitis and/or urticaria. Sensitization to class I digestion-resistant nut allergens usually occurs via the gastrointestinal tract and eventually via the skin and is associated with systemic and severe manifestations such as anaphylaxis but also mild symptoms are possible.