Brief overview
- Description: Allergy to certain plant pollens. Other names for hay fever: pollinosis, pollinosis, pollen allergy, seasonal allergic rhinitis.
- Symptoms: Runny nose, itchy and watery eyes, sneezing attacks.
- Causes and risk factors: Misregulation of the immune system, due to which the defense system sees proteins from pollen as dangerous and fights them. The tendency to allergies is genetically determined. Various factors probably contribute to the onset of the disease (e.g. excessive hygiene, tobacco smoke).
- Diagnosis: Taking a medical history, allergy tests (e.g. prick test, RAST).
- Treatment: Medication to alleviate symptoms, reduce allergen contact (e.g., ventilate at night instead of during the day, install pollen screens on windows); causal treatment by hyposensitization (specific immunotherapy)
- Prognosis: Mostly hay fever persists for life and increases without treatment. In addition, floor change is possible (development of allergic asthma). However, with proper treatment, symptoms can be relieved and complications avoided.
- Prevention: The tendency to allergies cannot be prevented, but the factors that contribute to the development of allergies can. This means, for example, not smoking during pregnancy and after birth, smoke-free environment for the child, full breastfeeding during the first four to six months.
It is estimated that on average almost one in four people in Europe suffers from allergic rhinitis, usually triggered by certain pollens. Such a pollen allergy (pollinosis, hay fever) is the most common form of allergy.
As with all allergies, in hay fever the body’s immune system overreacts to substances that are actually harmless – but not to hay, as the name suggests, but to proteins of certain plant pollens in the air (such as various grass and tree pollens).
Such pollen is not present in the air all year round, but only during the flowering period of the respective plants. Thus, the hay fever symptoms occur only in certain months of the year. That is why hay fever is also called seasonal allergic rhinitis (= seasonal allergic rhinitis, rhinitis allergica).
If you have hay fever-like symptoms all year round, you probably do not have hay fever, but another form of allergy (for example, to dust mites).
Hay fever: symptoms
People without hay fever can often hardly imagine how distressing the symptoms of a pollen allergy actually are: The itchy, watery eyes and the violent sneezing attacks with runny nose considerably restrict the quality of life of those affected.
You can read everything important about the typical signs of hay fever in the article Hay fever symptoms.
Hay fever: Causes and risk factors
As with all allergies, the symptoms of hay fever (pollen allergy) are caused by an excessive reaction of the immune system: The body’s defenses mistakenly classify the harmless proteins as dangerous and fight them like a pathogen:
In the process, certain immune cells – the so-called mast cells – secrete inflammatory messengers (histamine, leukotrienes) when they encounter the pollen proteins. These then cause the typical hay fever symptoms: the eyes, nose and throat are affected because the pollen proteins enter the body primarily through the mucous membranes.
Often, people with hay fever also develop allergies to certain foods. Doctors then speak of a cross-allergy.
How does the dysregulation of the immune system develop?
The processes involved in the development of pollen allergy are now well understood. However, there is only conjecture as to what ultimately triggers hay fever. Some risk factors probably contribute with great certainty to the development of hay fever:
Heredity
- If no family member is allergic, children have an allergy risk of about 5 to 15 percent.
- If one parent is allergic, the risk is about 20 to 40 percent.
- If both parents are allergic, the child has about a 40 to 60 percent chance of also developing an allergy.
- If both parents have the same allergy, the child’s risk of allergy is about 60 to 80 percent.
What’s more, those who are prone to allergies often don’t have just one. For example, neurodermatitis patients are often prone to hay fever, and many pollen allergy sufferers also can’t tolerate animal dander.
Excessive hygiene
It is possible that the degree to which the immune system is challenged during childhood also plays a role in the development of allergies (hay fever, etc.). The so-called hygiene hypothesis assumes that the body’s defenses are underchallenged when hygiene is very pronounced in childhood and therefore at some point also acts against harmless substances.
Tobacco smoke and other air pollutants
Substances in the ambient air that irritate the respiratory tract (fine dust, cigarette smoke, car exhaust, etc.) can contribute to the development of allergies (hay fever, etc.) and asthma. For example, children who grow up with parents who smoke have a greatly increased risk of later developing asthma, hay fever or other allergies.
But even smoking during pregnancy is dangerous for the child. The substances contained in tobacco smoke can lead to numerous malformations and developmental disorders in the unborn child (for example, in the lungs). Therefore, an expectant mother should never smoke during pregnancy. After birth, smoking should generally be taboo in the presence of the child.
More and more people suffer from hay fever
Experts from allergy societies suspect that the incidence of hay fever (pollen allergy) will continue to rise. They see one reason for this in climate change:
Rising temperatures worldwide are significantly extending the pollen season of many plants. The higher carbon dioxide (CO2) content in the air also stimulates plants to release even more pollen than before.
Air pollution by fine dust or ozone pollution also causes the pollen proteins to trigger even more violent reactions in humans. Researchers at the Max Planck Institute for Chemistry in Mainz assume that birch pollen, for example, is two to three times more aggressive due to a chemical reaction with ozone (O3).
Hay fever: examinations and diagnosis
The right contact person for suspected hay fever (pollinosis) is a physician with the additional title “allergology”. These are usually dermatologists, ear, nose and throat (ENT) doctors, lung specialists, internists or pediatricians who have completed additional training as allergologists.
Initial Consultation
During the first visit, the physician will first take the patient’s medical history (anamnesis) in a detailed discussion. In most cases, he or she will already be able to assess whether hay fever is the cause based on the description of the symptoms. Possible questions of the physician could be for example:
- Which complaints do you have?
- When exactly do the complaints occur, i.e. at what time of day and season?
- Where do the symptoms occur – outdoors or only indoors?
- Do you have any known allergies?
- Do you have neurodermatitis or asthma?
- Do your parents or siblings have allergic diseases such as asthma, hay fever or neurodermatitis?
- Where do you live (in the country, next to a busy road, etc.)?
Whether it is hay fever, the doctor can determine relatively reliably by the anamnesis interview alone. Identifying the triggering allergen, on the other hand, is sometimes very difficult and resembles detective work.
The first step is to look at the pollen calendar. There, the times are listed in which the various plants in a certain region usually release their pollen: For example, anyone who has typical hay fever symptoms as early as January is probably hypersensitive to the pollen of alder and/or hazel.
Examinations
The doctor examines the patient after the initial consultation. He looks especially at the nose (inside and outside) and the eyes.
Various diagnostic tests are available to identify the type or types of pollen to which someone is allergic. These allergy tests include skin testing, provocation testing and, if necessary, blood testing for antibodies to pollen proteins (IgE antibodies).
Three days before a skin test or provocation test, the patient should stop taking medications that suppress allergic reactions (for example, cortisone or antihistamines). Otherwise, the test result will be falsified. The physician will provide more detailed information.
Prick test
Read more about this form of skin test in the article Pricktest.
Intradermal test
If the prick test does not provide a conclusive result in the case of suspected pollen allergy, the test solution can also be injected into the skin using a thin needle.
Provocation test
The physician applies the suspected substance to the nose, bronchial mucosa or conjunctiva in the patient’s eye. If the reaction is positive, the mucous membranes swell and discomfort occurs. This test can lead to further, sometimes severe allergic reactions (up to anaphylactic shock). Therefore, the patient should remain under medical supervision for at least half an hour afterwards.
Blood test for antibodies
The “RAST” test can be used to determine whether certain antibodies (immunoglobulin E, IgE) against pollen proteins are present in the patient’s blood serum. If this is the case, this indicates sensitization to certain allergens, which, however, does not necessarily have to be accompanied by allergy symptoms.
Hay fever in children
Hay fever can also occur in babies and small children. Usually, the doctor does not perform a skin and provocation test on them. Both procedures are unpleasant for children. In addition, the offspring usually resists vehemently.
Hay fever during pregnancy
Hay fever: treatment
To treat a pollen allergy, the doctor has several options. Many patients are given medications that relieve the symptoms of hay fever. For mild symptoms, antihistamines in tablet form are the first choice. For moderate and severe hay fever symptoms, cortisone nasal spray is used – often in combination with antihistamines.
Another option for hay fever treatment is hyposensitization (also known as specific immunotherapy). This is an attempt to gradually accustom the immune system of the affected person to the pollen proteins.
You can read more about the various treatment options in the article Hay fever – Therapy.
Preventing hay fever symptoms
In order to avoid hay fever symptoms in the first place as a pollen allergy sufferer, you should avoid the critical pollen as much as possible. However, this is not very easy, especially since they float hundreds of kilometers through the air. They can therefore trigger hay fever symptoms even if the plants in question are not yet in bloom at the place of residence itself. However, the following tips can help to limit allergen contact as much as possible:
Pay attention to the pollen forecast
Get a pollen calendar
A pollen calendar provides hay fever sufferers with an approximate guide to when they can expect to experience symptoms. This can be very useful for vacation planning, for example. Pollen calendars are also available free of charge in almost all pharmacies.
Travel
Those who have the opportunity should travel to areas where the plants in question are not yet in bloom or are no longer in bloom during the pollen season of “their” plants. Alternatively, pollen allergy sufferers can also travel to regions where these plants do not occur at all, such as in the high mountains at altitudes above 1,500 meters, in coastal areas or on islands. There, the air is usually low in pollen.
Keep windows closed during the day
Pollen counts are usually most intense during the day. People suffering from hay fever should therefore keep the windows closed during the day and rather air out at night. Then less pollen enters the interior.
Air conditioners with air filters
Air conditioners with air filters can be quite useful for allergy sufferers. They clean the indoor air from pollen, among other things. However, it is important that the system is serviced regularly. Defective or dirty filters can additionally pollute the air with allergens.
Pollen screens on the window
Keep bedroom pollen-free
If you take off your street clothes outside the bedroom and wash your hair before going to bed, you will prevent pollen from spreading into the bedroom. Freshly washed laundry (such as bed linen) should not be left out to dry, as pollen can stick to it.
Clear living spaces of pollen
During the pollen season, it can be useful for hay fever sufferers to clean their homes daily. If possible, no pollen should be stirred up – for example when vacuuming. It is better to damp mop floors and furniture.
Pollen protection when driving
In the car, pollen allergy sufferers should turn off the ventilation and keep the windows closed. In many car models, it is also possible to retrofit the ventilation systems with pollen filters.
Use rain instead of sun
Rain reduces the concentration of pollen in the air. People with hay fever should therefore prefer to use rain showers and the time shortly afterwards for walks.
Hay fever: course of the disease and prognosis
Many sufferers have hay fever relatively early, i.e. in childhood or adolescence. However, it can ultimately occur for the first time at any stage of life.
Can hay fever be prevented?
The susceptibility to allergies (atopy) is inherited. But whether an allergy actually breaks out depends on other factors. For example, the mother’s diet during pregnancy and breastfeeding influences the risk of allergy in children. Experts also recommend that babies be fully breastfed for the first four to six months of life and continue to breastfeed after the introduction of complementary foods. This can also prevent allergies such as hay fever.
You can find out which other measures help to prevent allergies in the article Allergy – Prevention.
