Hay fever

Introduction

Anyone who suffers from hay fever is allergic to pollen. Hay fever is therefore also known as pollen allergy or, in technical terms, pollinosis. Other names for hay fever are seasonal allergic rhinitis or seasonal rhinitis allergica. An allergy is a hypersensitivity of the body to certain substances. Hay fever usually occurs seasonally. The typical pollen seasons are in spring, but increasingly also in summer or autumn. In most cases, those affected suffer from eye and respiratory problems as well as rhinitis.

Many allergy sufferers are not just allergic to one type of pollen but to pollen from different plants. As some plant species bloom as early as December, January or even into autumn, hay fever can also occur all year round or several times a year.

Around 1.5 million people in Switzerland suffer from hay fever. That is 15 to 20 per cent of the population. Hay fever is therefore the most common allergic disease - with a strong upward trend. The symptoms usually begin at school age.Viele Allergiker sind nicht nur gegen eine Pollenart, sondern gegen Pollen verschiedener Pflanzen allergisch. Da einzelne Pflanzenarten bereits im Dezember, Januar oder auch bis in den Herbst hinein blühen, kann Heuschnupfen auch ganzjährig oder mehrmals im Jahr auftreten.

Symptoms

The symptoms of a pollen allergy usually occur seasonally between spring and autumn, when pollen from trees, grasses and herbs fly through the air. The symptoms often worsen on dry and windy days, as the pollen count is then particularly high.
Hay fever causes typical symptoms in the eyes and nose. These include watery, burning, itchy, reddened eyes and swollen eyelids (allergic conjunctivitis) as well as an itchy, tingling, runny nose, sneezing fits and a swollen nasal mucosa, which, if left untreated, forces you to breathe through your mouth. After about a week, a reduced sense of smell can also occur. Together with the local symptoms, there is often a general feeling of illness with weakness, tiredness and fatigue, but without fever.

Progression

In 80 per cent of cases, a pollen allergy begins before the age of 30 and often lasts a lifetime. However, the proportion of patients who develop hay fever after the age of 50 is increasing. In many cases, the symptoms can be alleviated with treatment in the form of hyposensitisation and the course of the disease can be alleviated. If the condition is not treated, the allergy can move from the upper airways to the lower airways (bronchi), causing asthmatic symptoms.

A pollen allergy can also lead to a so-called cross-allergy to certain foods. In this case, the allergy-triggering pollen proteins and the proteins contained in the corresponding foods are similar. There are typical combinations of allergy-triggering pollen and foods: Sufferers who are allergic to hazel, alder or birch pollen, for example, may also be allergic to hazelnuts, apples or cherries. These patients can develop the typical symptoms of a food allergy.

The symptoms of a pollen allergy can diminish with age, but can also occur again. As a result, hay fever is no longer exclusively assigned to a specific age group.

Causes

Hay fever is caused by an excessive allergic reaction to pollen. In the case of an allergy, the body reacts hypersensitively to certain substances and proteins. The body's defence system mistakenly classifies harmless proteins in the pollen as dangerous and fights them like a pathogen. Hay fever is triggered by contact with pollen from a wide variety of plant species - for example, grasses, cereals, trees, shrubs, herbs or fungi. During the immune system's defence reaction, substances are released that can lead to typical symptoms such as red and itchy eyes, sneezing and itchy and swollen nasal mucous membranes.

Many allergy sufferers are not just allergic to one type of pollen but to pollen from different plants. As some plant species bloom as early as December, January or even into autumn, hay fever can also occur all year round or several times a year.

A predisposition to a pollen allergy is hereditary; air pollutants can also favour hay fever or exacerbate the symptoms by contaminating the pollen.

Diagnosis

To diagnose hay fever, the doctor first conducts a detailed discussion with the patient (known as a medical history). The doctor will ask the patient about the allergic symptoms or whether other family members are also affected by allergies. If the symptoms of the allergy described occur during typical pollen seasons, it is very likely to be hay fever. The doctor will also check whether conjunctivitis or skin changes in the upper respiratory tract are present. An examination of the eyes and nasal entrance area can also be easily diagnosed by telemedicine using a sent image.

The trigger of the pollen allergy can be determined using an allergy test. In a so-called prick test, the doctor drops various pollen extracts onto the patient's forearm or back. The doctor then pricks the skin under the drop with a needle: In the case of an allergy, the areas redden after 20 minutes, swell slightly and may also itch. A blood test for antibodies against the respective allergens can also confirm the previous results.

Treatment

In the case of an allergy, it is fundamentally important to avoid the allergens that trigger it. However, this is difficult in the case of a pollen allergy, as the pollen often flies for kilometres. In addition to avoidance, the following additional treatment measures are available for pollen allergies:

• Specific immunotherapy (SIT) - hyposensitisation - not only treats the symptoms, but also the cause. This involves a doctor injecting increasing doses of the allergy-causing substance under the skin. The aim is to get the immune system used to tolerate the allergen. In the long term, this therapy can not only alleviate the symptoms, but also prevent the allergy from spreading, the affected organs from expanding and the disease from becoming chronic. Such hyposensitisation usually lasts three to five years.
• A special form of hyposensitisation is known as sublingual immunotherapy (SLIT). This involves administering drops of a pollen solution directly under the tongue (also in increasing doses). Another form of this immunotherapy is the intake of so-called grass tablets. Here, a tablet containing pollen from various types of grass is dissolved under the tongue. This specific form of hyposensitisation is less effective and reliable.
• Acute symptoms of hay fever can be alleviated or eliminated with medication. Active substances that belong to the group of so-called antihistamines are often used. These active ingredients prevent released histamine from binding to other cells: This interrupts the allergic reaction and alleviates the symptoms. In many cases, antihistamines do not have a strong enough effect to stop an allergic reaction - as a result, eye drops, nasal sprays or tablets containing cortisone are used.
• Specialised skin care products can help to alleviate symptoms such as itching or burning of the skin. Nasal rinses with boiled or sea salt solution activate the cilia in the nasal mucosa. These cilia remove impurities - especially pollen from the upper airways - and thus cleanse the nose of pollen. In the case of acute hay fever, this leads to significant relief of symptoms.

If hay fever remains untreated, there is a risk that the immune system will react allergically to more and more substances or that the pollen allergy will develop into allergic asthma.

Prevention

Those affected can only prevent hay fever to a limited extent. There is therefore no actual protection against a pollen allergy - however, patients can try to reduce their symptoms by taking certain measures:

• Avoiding pollen sources such as flowering meadows or trees.
• Avoid smoking, smoky rooms and swimming in chlorinated water (tobacco and chlorine further irritate the airways).
• Use pollen filters and air conditioning in cars and use special filters when vacuuming.
• Wash your hair before going to bed and do not take your clothes into the bedroom; sleep with the windows closed.
• Change bed linen regularly and do not dry it outside during the pollen season.