If our bodies come into contact with substances that are alien to them or could pose a potential danger to them, they trigger a defense mechanism. One of these substances is allergens. These are primarily tiny proteins that, generally speaking, do not constitute a threat to the organism.
However, people with allergies develop special antibodies which lead to the release of various tissue hormones in our skin and mucous membranes. The most important of these hormones with regard to allergic symptoms is histamine: it is responsible for many of the body's allergic reactions, like itching, shortness of breath or increased dilation of blood vessels.
The immune system is activated the first time the body experiences the allergen. This process then occurs every time renewed contact takes place. This means if the body has reacted allergically to a substance once, it never forgets. Repeated contact with the substance very quickly leads to an allergic reaction – usually in a matter of minutes, but it can sometimes take up to an hour.
The reaction of the eyes is particularly severe: the conjunctiva and mucous membrane react to the foreign substance immediately, the blood vessels dilate and fluid is released. We experience this in the form of tears, a runny nose, swelling or reddening. The tears gradually flush the allergens out of the eyes, therefore slowly alleviating the symptoms.
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