ALLERGY, DRAWING. Allergic reaction to pollen. Phase of trigger to the allergy second contact with the allergen, sensibilized individual. The allergens pollen grains penetrate into the respiratory mucosa and come to fix to the corresponding antibodies Ig E at the periphery of a mast cell focus on the recognition of the allergen, triggering the release of histamine that provokes the allergic reaction : running nose, stinging eyes etc.