Medical Encyclopaedia › Hay fever (short definition)
In brief: Hay fever, technically seasonal allergic rhinitis, is an excessive reaction of the immune system to pollen from trees, grasses or weeds. It is one of the most common allergic diseases.
Symptoms
Typical symptoms are bouts of sneezing, a runny or blocked nose, itchy, watery and red eyes and an itchy throat. Many of those affected feel tired and less productive. If untreated, the allergy can spread to the lower airways and lead to asthma (the “allergic march”).
Triggers and pollen seasons
In Central Europe, hazel, alder and birch pollen are mainly in the air in spring, grass and rye pollen in early summer and mugwort and ragweed in late summer. As a result of climate change, pollen seasons tend to start earlier and last longer. Many people with pollen allergy also react to certain types of fruit or vegetables (cross-allergy).
Diagnosis
In addition to the medical history, a skin prick test and measurement of specific IgE antibodies in the blood help to identify the triggers.
Treatment
Pollen can never be avoided completely, but washing your hair before going to sleep, airing rooms at times of low pollen and pollen screens help. Modern antihistamines such as cetirizine or loratadine, corticosteroid nasal sprays and anti-allergic eye drops relieve the symptoms. Decongestant nasal sprays should only be used for a few days. The only treatment that addresses the cause is allergen immunotherapy (desensitisation) over three years, which can reduce the risk of asthma.
When to see a doctor?
In the case of severe or persistent symptoms, shortness of breath, wheezing, or if over-the-counter remedies are not sufficient, an allergy assessment is advisable.
Related terms in the encyclopaedia
Allergy, Rhinitis, Antihistamine, Cetirizine, Loratadine, Allergen immunotherapy, Prick test, Cross-allergy, Bronchial asthma
Sources
- Deutsche Gesellschaft für Allergologie und klinische Immunologie (DGAKI): Leitlinie zur (allergen-)spezifischen Immuntherapie bei IgE-vermittelten allergischen Erkrankungen
- ARIA (Allergic Rhinitis and its Impact on Asthma): Leitlinien zur allergischen Rhinitis
- Stiftung Deutscher Polleninformationsdienst: pollenstiftung.de
- IQWiG: gesundheitsinformation.de – Gesundheitsinformationen des Instituts für Qualität und Wirtschaftlichkeit im Gesundheitswesen
Note: This article is for general information and does not replace advice, diagnosis or treatment from a doctor or pharmacist. Last updated: October 2026.