Enjoy spring without itching

What is a pollen allergy?

Pollen allergy, also called hay fever, is one of the most common allergic conditions and affects up to 20–30% of the population in Europe depending on the region. The immune system reacts to otherwise harmless pollen – microscopic reproductive units of plants – with an excessive defence response.

Pollen from wind-pollinated plants easily reaches the airways. In genetically predisposed people, the immune system mistakenly recognises these as a threat and releases mediators such as histamine, which trigger typical symptoms. As a type I allergy, symptoms usually occur within minutes of exposure.

Symptoms are often seasonal and depend on the prevailing pollen flight times. While many people experience symptoms mainly in spring and summer, early- or late-flowering plants can cause problems to start in winter or persist into autumn.

What are the symptoms of a pollen allergy?

An allergic rhinoconjunctivitis is typical for a pollen allergy. It presents with sneezing, a runny or blocked nose and itching of the nasal mucosa. The eyes are also often affected, with redness, watering and swollen eyelids. Some people additionally develop sinusitis or a middle ear infection.

There can also be systemic symptoms such as tiredness, headaches or concentration problems. In some people, an allergic asthma (a “level change”) may develop over time, accompanied by cough, breathlessness and a tight feeling in the chest.

The severity of symptoms depends, among other things, on the pollen concentration in the air. Cross-reactions are also possible: the immune system may react to certain foods whose proteins resemble pollen allergens, causing, for example, itching in the mouth.

Which plants produce allergenic pollen?

Many plants produce pollen that can trigger allergic reactions. Particularly relevant are wind-pollinated species, whose pollen can be carried over long distances.

Important triggers include early-flowering trees such as hazel and alder. Birch pollen is also highly allergenic and is often associated with cross-reactions, for example with apple or hazelnut (oral allergy syndrome). Other relevant trees include ash and alder.

Grasses are among the most common and clinically significant causes of allergy. These include rye, meadow fescue and timothy grass. They produce large amounts of pollen and dominate pollen release from May to July.

Herbs such as mugwort and ragweed also play an important role. Ragweed is particularly problematic because its pollen is highly allergenic and can cause symptoms even at low concentrations.

In individual cases, houseplants can also cause complaints. However, it is usually not the pollen but plant proteins or latex-like substances that are responsible.

Does hyposensitisation help against pollen allergy?

Specific immunotherapy (hyposensitisation) is currently the only treatment that addresses the underlying cause of the allergy. The aim is to gradually accustom the immune system to the allergens and to reduce the overreaction.

The therapy usually lasts at least three years. Clinical studies show that it can significantly reduce symptom severity and medication requirements. Initial improvement may already occur in the first year of treatment.

Treatment is given either as subcutaneous immunotherapy (SCIT) by injections or as sublingual immunotherapy (SLIT) in the form of drops or tablets. Both methods are effective but differ in application and side-effect profiles.

Hyposensitisation is suitable for allergies tograss, cereal, herb and tree pollens. Its advantage over other treatments is that it not only relieves symptoms but can also reduce the risk of secondary conditions such as allergic asthma or cross-allergies. However, it does not work equally well for all patients and in some cases symptoms remain or recur after treatment.

How is hay fever diagnosed?

Diagnosis is made step by step and begins with a detailed medical history. Symptoms, their time course and possible triggers are recorded.

A central component is the prick test, in which allergens are applied to the skin and the surface is lightly pricked. A local reaction in the form of redness and swelling indicates sensitisation.

A blood test can additionally be performed to determine specific IgE antibodies. It is important to note, however, that a positive test alone does not prove a clinically relevant allergy and must always be interpreted in the context of symptoms.

In unclear cases, a provocation test can be carried out, in which allergens are deliberately applied to the mucous membranes of the nose or eyes. This examination is particularly informative but is used only selectively because of the effort involved and possible reactions.

 What helps for hay fever: useful tips

• Reducing contact with triggering pollen can significantly reduce symptoms – however, it is hardly possible to avoid them completely in everyday life. Non-drug measures can nevertheless provide noticeable relief.
• Use current pollen forecasts (e.g. via apps or weather services) to avoid periods of high exposure as much as possible.
• Keep in mind that air pollutants can enhance the allergenic effect of pollen. Especially in busy traffic areas or under certain weather conditions this can lead to increased symptoms.
• Schedule sports activities, if possible, at times of lower pollen exposure or do them indoors.
• Keep car windows closed and use pollen filters in ventilation or air conditioning. Regular filter changes are important to maintain effectiveness.
• Pollen concentration varies by region and time of day. Instead of fixed airing times, it is sensible to follow current pollen levels. During high-exposure periods it can help to keep windows closed.
• Avoid additional irritants such as cigarette smoke or heavily chlorinated water, as these can irritate the mucous membranes and worsen symptoms.
• If your eyes are irritated, wear sunglasses rather than contact lenses to reduce direct contact with pollen.
• Clean smooth floors regularly with a damp cloth and use vacuum cleaners with HEPA filters. Wiping surfaces can also reduce indoor pollen load.
• Change bed linen regularly and avoid leaving worn clothes in the bedroom to reduce transported pollen.
• Do not dry laundry outdoors during the pollen season if possible, as pollen can adhere to it.
• Wash your hair before going to bed to remove pollen and reduce exposure in bed.
• Decongestant nasal sprays should only be used short-term (a few days), otherwise they can cause dependence. Anti-allergic medications such as antihistamines or corticosteroid nasal sprays can effectively relieve symptoms and should be used regularly if needed.
• A nasal rinse with isotonic saline can be helpful by mechanically removing pollen from the nasal mucosa. 
• Even milder symptoms should be taken seriously, as early treatment can help prevent worsening or progression of the condition.

A pollen allergy can considerably affect daily life. Through a combination of allergen avoidance, appropriate medication and adapted behaviour, symptoms can often be well controlled.