Everybody who has a food allery knows how uncomfortable it is. But what is happening in our body when we get an allergic reaction?
First it is important to know, that an allergy reaction caused by food is the same as caused by pollen, dust or something else. The origin is always a protein. The first contact with this protein (the allergen) is harmless. The body just produces antibodies. The second contact with the allergen will be more dramatic, even if it is years later, because the allergen will react with the antibodies which are fixed on mast cells. Through this reaction the mast cell is going to spread mediators (eg. Histamine) which cause the allergic reaction.
Food protein are sometimes very similar to pollen or other protein. This is the reason why cross allergies are possible. The body reacts with another protein whose structure is similar to the allergen.
The best way to prevent an allergic reaction is to know the allergen which you are allergic and to avoid its consumption.