A hypersensitive immune system can give rise to an allergy. According to the European Centre for Allergy Research Foundation there are around 13 million allergy sufferers in Germany. Most people suffer from a pollen allergy which can manifest in the form of hay fever. However, other allergens can also cause allergy symptoms. For example, there are food allergies to nuts and celery or allergies to house dust. These allergies are included in the same allergy category as hay fever: type I. A type I allergy is the most common form of allergy and is characterised by the fact that people react to the corresponding allergens within an extremely short time.
How an allergy develops is still not fully understood. However, it is clear that the immune system reacts to a harmless substance by activating the defence system. Various cells of the immune system, such as lymphocytes and mast cells, are involved in the allergic process. According to the hygiene hypothesis, the immune system reacts so severely due to the fact that it was not properly trained in childhood. Improved food hygiene, the modern way of life and drugs such as antibiotics ensure that children today rarely come into contact with bacteria, parasites or viruses.
However, gut flora also play a role. On the one hand, the intestinal mucosa forms a barrier between the outside world and the inside of the body. If the intestinal mucosa cannot perform this barrier function due to inflammatory processes or bowel disease, undesirable substances pass through the leaky gut into the blood stream. If the intestinal mucosa has holes, this is referred to as leaky gut syndrome. Present allergies can worsen or new allergies can develop due to this. On the other hand, if the composition of the gut flora is not right more histamine is produced.
Histamines promote allergic responses. Histamines from the diet also have this effect with the result that allergy sufferers should avoid foods containing histamine such as salami, red wine, sauerkraut, cheeses that have matured for a long time, mould cheese and tuna fish.
However, the response of the immune system is influenced not only by the gut, but also the psyche. Stress and other psychological factors may trigger or worsen allergic symptoms if there is an allergic Disposition.