Definition
Hay fever is an allergic reaction of the body to actually harmless environmental substances. The name is slightly misleading and should not be understood as an allergy to hay. Those affected do not have problems with contact with hay, but react allergic to plant pollen. The allergic reaction is an overreaction of the own immune system and manifests itself with an inflammatory reaction of the respiratory tract. Especially mucous membranes are affected by the inflammation and show the typical symptoms.
Causes of hay fever in children
The cause for the development of hay fever lies in the way our immune system deals with harmless environmental substances. In some people, the immune system mistakenly recognizes pollen as a dangerous environmental substance, so that it is called an allergen. The pollen taken in through the air, for example, activates cells of the immune system and triggers the formation of antibodies in the affected person, which have the goal of neutralizing the pollen.
This reaction of the body makes sense in terms of evolution and sometimes also serves to defend against parasites. The antibodies belong to a special class called IgE. The IgE in turn binds to the body’s defense cells, which are called mast cells.
If the IgE activates the mast cells, they release the hormone histamine, which triggers an inflammatory reaction. In this way, defense cells can be lured to their destination and eliminate the allergens. In hay fever, the body reacts excessively to an allergen and produces relatively too many antibodies.
As a result, the inflammatory reaction triggered exceeds what is necessary. It is important to know that hay fever does not develop on first contact with the pollen. When pollen meets the immune system’s defense cells for the first time, this only leads to antibody formation and not yet to an inflammatory reaction.
In medical terminology this is called sensitization. Only the second and subsequent contacts trigger the typical symptoms, as the immune system remembers the allergen through the first contact and can trigger a directed defense reaction of the body. A recommendation of our reaction: Allergies in children
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