Hay fever - the role of the immune system

Many suffer from hay fever. Despite its name, however, the disease has little to do with hay: it is not the dried grass that triggers the symptoms, but the pollen of freshly flowering trees, grasses or herbs. There are hardly any pollen left in the hay. In the last twenty years, allergic diseases have greatly increased, especially in the rich countries of the northern hemisphere. Today, allergies in regions with "western" lifestyle are among the most common chronic diseases.

More and more allergies

The predisposition to allergic reactions is inherited. It can be detected in Switzerland by about 30 percent of adults and at least 35 percent of schoolchildren. Responsible for the rise of hay fever and asthma is probably our "hygienic" lifestyle as well as our usual apartments with carpets, heaters and double-glazed windows, in the interior of which an increased concentration of irritants is often found.

Another factor for the increased occurrence of allergies: the declining number of children. Our children are less likely to come into contact with pathogens. The frequent defense against such pathogens in early childhood but ensures that our immune system is sufficiently trained. The defense of our infants is increasingly "underemployed" and has time to get "stupid" thoughts.

Land children less endangered

This theory is underpinned by a Swiss study that has shown that six to fifteen-year-old peasant children suffer less frequently from allergic diseases than their peers. Your chance of contracting hay fever is three times lower than non-farm children.

Day nurseries and nurseries seem to have the same effect: the more children are together, the higher the likelihood of infections, ie effective immune defense training. In any case, this explains why children in former East Germany suffer less from allergies. Until recently, a large proportion of the children were accommodated during the day in crèches.

Wind pollinators make you sick

In trees, grasses and herbs, the wind blows the male pollen away from the flowers and, with a bit of luck, to the female reproductive part of another plant of the same species. This process is called wind pollination and ensures the fertilization of the egg. In order for the wind pollinators to have a chance to reproduce further, they have to produce enormous amounts of pollen: rye brings it to 21 million, sorrel even to 400 million pollen per plant. In addition, pollen must be as light as possible, so that the wind carries it well.

Pollen grains are therefore so small that they are practically invisible to the naked eye (8 to 100 thousandths of a millimeter). In addition, trees usually flower before the leaves unfold, so that the pollination is not hindered by the leaves. Every year, we breathe in about one thousandth of a gram of pollen grains. This minimum amount is enough to plague more than a fifth of the population with hay fever. Of the 3500 plants occurring in Switzerland, only about 20 are of importance for allergy sufferers.

This is how hay fever begins

Although signs of hay fever can appear in children as young as five to six years old, pollen allergy is a typical disease of schoolchildren. Sometimes it even makes itself felt at puberty. The peak of the complaints is usually reached between the age of 15 and 25 years. But older people are increasingly suffering from hay fever. So you have to think of over 70-year-olds with symptoms similar to a pollen allergy.

Hay fever often begins with an annoying itch in the eyes, as if small grains of sand had fallen into it. The eye responds with increased tear production, the conjunctives redden, with particularly strong reaction they also swell. Eye rubbing increases redness and swelling. For some people, the eye symptoms are harder to bear than the flowing, itchy nose. The nose bites and triggers a violent sneeze. Cascades of sneezing attacks are typical for allergic rhinitis. They can be very strong and lead to exhaustion in severe cases.

The nose produces unlike a cold much thin, clear secretion. The pollen allergy always occurs at the same time of year, especially in fair weather. In the rain, the patients are much better. Unfortunately, many pollen often fly through the air after the rain. The whole thing starts all over again. In many patients, the hay fever complaints become less over the years or even disappear altogether. But they remain sensitive throughout their lives and can always develop a different allergy (to food, pets or latex).


Hay fever patients often suffer from irritated or blocked airways for weeks to months. The inflamed nasal mucous membrane also reacts sensitively to other stimuli: Dust, cigarette smoke or temperature changes bring the nose to flow again weeks after the fading of hay fever.

In about one third of hay fever is allergic to asthma. This process is called a "level change" because the disease has changed from upper to lower respiratory tract. This complication turns a harmless allergy into a potentially dangerous one and is therefore particularly dreaded. By timely and correct treatment of hay fever, the change of floors can often be prevented.

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