In Germany, about a quarter of the population suffers from an allergy – about half of them from hay fever. Allergies have now become a real widespread disease and are increasingly affecting young people and children. More and more people are becoming sensitive to rather harmless substances, to normal things in everyday life and the environment, for example pollen, house dust, animal hair, the sun, food or chemicals. Why does the immune system react hypersensitively to certain substances and what can everyone do themselves to protect themselves?
What is an allergy?
Allergy is the acquired hypersensitivity (hypersensitivity) of the body to substances of the living environment. The allergic reactions are basically normal immune responses, but they are misdirected.
The immune system is then no longer able to distinguish between harmful and harmless substances and, in addition, produces too many antibodies, resulting in an excessive allergic reaction. The defense system thus damages its own body. Each new contact with the allergen (allergy-causing substance) then sets this reaction in motion again.
The defense processes
To cope with unwanted and potentially dangerous invaders such as viruses or bacteria, the body has various defense strategies. One of these is to capture the invaders (= antigens) with antibodies and then render them harmless.
- Antibodies are proteins in the blood that the body matches precisely to the antigen in question. In an allergic reaction, the antigen is also called an allergen. In the course of the first contact, the antibodies are first produced – nothing else happens yet. Attackers and defenders (the immune system) must first get to know each other, so to speak.
- At the second contact, however, a fierce wave of defense rolls in. The antibodies circulate not only in the blood, they also migrate into the tissues. In the lymphatic system, in the mucous membranes of the nose and mouth, in the respiratory tract and in the intestines, they encounter another type of defense cells, the mast cells. These contain numerous granules in which messenger substances such as histamine are stored. On their surface they carry binding sites for antibodies (receptors). There is room for up to 100,000 antibodies on a single mast cell. An antibody looks like a ypsilon. It has one leg and two arms. The leg binds to a mast cell, the arms catch intruders (= antigens) and hold them. If two antibodies have caught one and the same intruder, so that it hangs like a bridge between the two antibodies, the mast cell releases the messenger substances stored in the granules.
- These messengers are quite aggressive. If they get out of the mast cells into the surrounding tissue, they cause small inflammations there. In addition, the blood vessels dilate. Depending on where this process is currently taking place, a wide variety of symptoms occur: Itching, sneezing, runny nose, burning, watery eyes, skin reactions, etc..
