Hay fever is increasing, especially in the cities. Although the allergy can develop into asthma within a few years, those affected and even doctors do not take hay fever seriously and do not treat it adequately. There are effective therapies available to prevent the body’s allergic reaction.
Hay fever seems to be one of the widespread diseases with the highest growth rates. In recent years there has been a twenty-fold increase. Around 15 percent of adults and almost ten of children now have a pollen allergy. “Several factors are responsible for this increase,” says Knut Brockow, senior physician in the allergy department at the Clinic for Dermatology and Allergology at Biederstein, Klinikum rechts der Isar, TU Munich.
Why pollen allergies are increasing so significantly
On the one hand, there is the modern lifestyle with excessive hygiene. “If we have less contact with bacteria and parasites, the immune system can turn against harmless substances, which we then call allergens, and which trigger symptoms,” says the allergist, naming an important risk factor.
It is known that allergies are increasing particularly rapidly in cities because the bacterial diversity there is much lower than in rural areas. Children who grow up with many siblings, who have daily contact with animals and who stay in the cowshed have a much lower risk of allergies. Bacterial diversity protects against allergies, so to speak.
Heavy traffic means a high risk of hay fever
The other reasons for the increase in pollen allergies:
Due to the climate catastrophe, the flowering times have been extended by many weeks.
New allergens, such as ragweed, are an additional burden for allergy sufferers. The undemanding herb was brought in from the USA by airplanes, first reproduced at military bases and now along the highways. Its pollen is much more aggressive than that of our native plants and can trigger an allergy particularly quickly.
“Air pollution also plays a role,” warns the expert. Although the air in Germany is less polluted with large particles than it used to be, fine dust and soot particles, for example from cars with internal combustion engines, have increased in some cases. They have been shown to increase the allergenic effect of pollen.
It is therefore obvious that city dwellers are probably particularly at risk for pollen allergies. “Anyone who lives on a busy street has a higher risk than in a neighborhood with little traffic,” explains the professor.
Hay fever – first sensitized, then allergic
The mucous membranes of the eyes, nose, throat and bronchi play an important role in the development of a pollen allergy. If pollen gets on the mucous membranes, the immune system reacts more intensely in some people. Right from the first contact, white blood cells (lymphocytes) cause antibodies (E-immunoglobulins, IgE) to be formed against the pollen proteins – as if these actually harmless proteins were pathogens. After this sensitization, the immune system reacts with every further contact with the corresponding pollen: IgE antibodies are formed, settle on mast cells, these react and release the inflammatory messenger substance histamine, among other things. This triggers the cascade of allergic symptoms, in hay fever these are:
- Itchy eyes, tears in the eyes
- Runny nose
- Stuffy nose
Hay fever is usually not treated properly or not at all
Most of those affected often suffer for decades and fail to get proper treatment, experiment with over-the-counter products that are often not taken properly, for example too short. For example, many stop self-treatment because the antihistamines hardly help. This is the case when the pollen allergy is quite severe.
“Hay fever is simply not taken seriously enough,” remarks Knut Brockow. Many patients often see no need for action because the complaints “only” occur temporarily. When it rains or the flowering time of the allergenic plant is over, the hay fever symptoms will also disappear again.
But this trivialization would not only apply to the patient, but also to the doctor, such as the family doctor, who is the first point of contact for most people with hay fever. They underestimate the problem of a pollen allergy and do not refer the patient to an allergist.
The consequences of hay fever – allergic to more and more pollen and asthma
Not treated or not treated adequately, hay fever can get worse and worse. The expert warns that this risk exists especially in the years after the first occurrence of the pollen allergy. This is how the allergy can spread. Initially, it is resistant to grass pollen, for example, then birch and alder are added, possibly also house dust mites.
In addition, the allergic symptoms can become so severe that the person affected is really sick and cannot work. “It was not for nothing that people used to speak of ‘hay fever’ because it can paralyze you,” explains the scientist. The head is closed like a flu.
However, there is a particularly high risk of bronchial asthma resulting from hay fever. Asthma is known to be chronic, incurable and can occur all year round. This level change from pollen allergy to asthma is possible because the mucous membrane of the nose and lungs form a unit and can react together. “Children up to six years of age diagnosed with hay fever have been shown to have three times the risk of asthma than others,” reports Knut Brockow.
Therapy: Antihistamines are usually not a permanent solution
Hay fever should therefore best be clarified by an allergist, who can use allergy tests to determine which pollen the body reacts to and to what extent. Then the appropriate treatment is initiated.
Self-treatment with antihistamines is usually no solution to the hay fever problem. Because they do not target the cause of the hay fever, the misdirected immune reaction, but only slow down the symptoms. “These drugs only reduce the effects of histamine on the organs, but they cannot adequately influence the development of the allergy,” explains the expert. That is why antihistamines are only recommended for mild, sporadic allergic symptoms, but not for complaints that last for several days.
Cortisone nasal spray for hay fever
Then corticosteroid-containing nasal sprays should be used as a stronger therapy. “The prescription of corticosteroids as a nasal spray is far too seldom used for hay fever,” criticizes the allergist. Many doctors do not know how useful the active ingredient is for pollen allergies because it has a positive effect on inflammation.
The cortisone nasal sprays are also available in combination with antihistamines. They treat the symptoms much better than oral antihistamines and are suitable for patients whose symptoms do not increase and who do not have any initial asthma symptoms (slight shortness of breath, slight cough) such as coughing.
Specific immunotherapy addresses the cause of the allergy
However, both drugs – corticosteroids and antihistamines – only treat symptoms. If the hay fever is severe or worsen, it is best to treat the cause of the disease and not just treat the symptoms. This is where specific immunotherapies (SIT) come in. The desensitization or colloquially also known as “vaccination” against hay fever means: The immune system is slowly, with initially minimal doses, used to the triggering allergen until the body reacts normally to the actually harmless substance. “These therapies are very effective, especially when the allergy has only one trigger, such as grass pollen, but are also used far too seldom – because the patient does not even know that this is possible, as does the first-aid doctor,” explains the expert,
Desensitization means: the immune system learns tolerance to pollen
How these therapies work: The prerequisite is the identification of the triggering pollen through the appropriate allergy tests. By far the most common triggers are grasses, birch, alder and hazel. Those affected can already be hyposensitized to them. Two forms of SIT are currently available:
- subcutaneous immunotherapy (SCIT, regular injections of the allergens under medical supervision for about three years)
- sublingual immunotherapy (SLIT, drops or tablets with the corresponding allergens, which the patient takes independently as instructed by the doctor, also over a period of three years)
SCIT has established itself particularly well, “The advantage here is that the doctor carries out the treatment and thus the cooperation of the patient is guaranteed,” emphasizes Knud Brockow. In recent years, however, SLIT has also proven itself more and more and is almost as successful as subcutaneous immunotherapy. The sublingual variant is particularly suitable for patients who have less time and want to carry out the treatment at home.
New therapies: more targeted and fewer side effects
In the future, the desensitization should have an even more specific effect, but trigger fewer side effects. These include itching and swelling in the area of application, i.e. in the mouth or the injection site. Systemic allergic reactions are also rarely possible.
“That is why one tries to change the allergens administered in such a way that they respond less to the mast cells and thus trigger fewer allergy symptoms, but to better address the T lymphocytes, which are supposed to generate allergen tolerance,” the allergist explains the new research approach. Researchers try, for example, to only use the individual molecular proteins in the pollen that trigger the allergy. In the case of birch pollen, for example, this is Bet v 1. However, further research has to be done on this.
- In addition, new forms of administration for desensitization are being tested, for example as plasters. This epicutaneous desensitization (pollen patch) could simplify SIT compared to sublingual and subcutaneous application.
- Another research approach could provide a particularly elegant solution, an antibody against the immunoglobulin IgE, the allergic reagin. This would block all IgE molecules in the body. They can no longer dock on the cell surfaces and thus trigger the allergy. The antiallergic effect would start earlier than that of the antihistamines at one point.
Anti-IgE antibodies will not only work against pollen allergies, but also against other allergies that take place via this mechanism. “Corresponding drugs are currently not yet approved for this and are still too expensive, but if they are further developed they would be a sensible therapy option,” says the expert.
These drugs (omalizumab) have already been approved for the treatment of severe, uncontrollable allergic asthma and urticaria.
Conclusion : If the symptoms of hay fever persist for more than a week, are very pronounced and / or if there is a cough, an allergist should definitely clarify the symptoms. Because if left untreated or not adequately treated, the allergy can spread and the person affected reacts allergically to more and more stimuli. There is also a risk of changing floors and asthma in addition to hay fever. But almost everyone who suffers from a pollen allergy today can be helped. Modern therapies such as desensitization slowly and carefully get the immune system used again to react normally to the actually harmless pollen.