Introduction

Many children and adults are affected by hay fever in the spring and summer months, when plants grow and bloom. Sneezing and itchy eyes can be a real problem, especially on days that are warm and dry. A lot of people who have allergies and asthma have more asthma attacks around this time of year too.

Hay fever is an allergic reaction to pollen in the air, affecting the upper airways. The medical term for the symptoms it causes is allergic rhinitis.

At a glance

• Allergic rhinitis (sneezing and a runny or stuffy nose) is the main symptom of hay fever.
• These symptoms occur only during the pollen season.
• Tablets and nasal sprays can relieve the symptoms.
• Immunotherapy (desensitization) may help to reduce the symptoms over time.

Symptoms

People who have allergic rhinitis sneeze a lot and have a runny or stuffy nose. If their symptoms are more severe, they might also feel weak and tired. Sometimes people have watery and itchy eyes too, and their eyelids become swollen. The medical term for this is allergic rhinoconjunctivitis (allergic rhinitis combined with conjunctivitis). Other possible hay fever symptoms include itching and asthma-like symptoms such as coughing, wheezing, and shortness of breath.

These symptoms only occur during the pollen season. They are usually much more noticeable than the symptoms of a dust mite allergy, but don't last the whole year.

Causes and risk factors

Allergy symptoms arise when your body overreacts to particular substances that are usually harmless, such as pollen. These substances (allergens) trigger a chain reaction in the immune system. First, antibodies to the allergen are made, and they bind to specific cells. If these cells come into contact with the allergen again, they are then able to “respond” by releasing chemical substances such as histamine. These substances then lead to allergic reactions such as sneezing or itchy eyes.

The following table shows which plants commonly cause allergic reactions and when pollen from those plants is typically in the air:

Some plants are now blooming earlier, for a longer time and more due to higher temperatures throughout the year caused by climate change. This increases the amount of pollen in the air and how long pollen season lasts.

Sometimes a higher risk of allergies runs in families. Environmental factors such as air pollution and cigarette smoke can make allergies more likely.

Allergies are quite common nowadays. This may be partly due to higher standards of hygiene and the fact that some infections have become less common in childhood. As a result, our immune systems are often not as “well trained” as they might have been in the past.

Prevalence and outlook

Hay fever affects about 1 out of 4 people in industrialized countries like Germany. It usually first arises before the age of 20.

The allergic rhinitis symptoms may "move down" into the lungs and develop into allergic asthma after several years. Sometimes people who have a pollen allergy become allergic to certain foods too after a while (a phenomenon known as cross-reactivity).

Severe hay fever may increase the likelihood of developing other medical conditions such as sinusitis (inflammation of the sinuses). Hay fever often makes the mucous membranes lining the airways overly sensitive in general too. As a result, they may also react more strongly to irritants like dry air in heated rooms or cigarette smoke.

Diagnosis

If you see a doctor, you will first be asked about your symptoms, your everyday life circumstances, and medical history. The doctor can then do a skin prick test to find out whether you are allergic to particular substances. This involves placing small drops of various allergens on the skin of your forearm, leaving enough space between them, and then pricking the surface of your skin where the allergens are, so the substances go into the skin. If your skin becomes red and swollen, like a big mosquito bite, you have had an allergic reaction to that substance.

You might also need a blood test or something known as a provocation test. This is where the membranes lining the nose or the eyes (conjunctiva) are exposed to extracts of the potential allergen using a nasal spray or drops. If the lining of your nose becomes swollen, you sneeze and your nose starts running, you are likely to have allergic rhinitis.

Prevention

It is nearly impossible to protect yourself from pollen, unless you travel to areas of the world where there is currently no pollen in the air. You can minimize the effects of pollen by keeping windows closed and washing your hair before going to bed. Local weather reports often provide information about pollen forecasts and current pollen counts.

Treatment

The symptoms can be treated with various medications:

• Antihistamines
• Steroids (corticosteroids)
• Chromones (mast cell stabilizers)
• Leukotriene receptor antagonists
• Decongestant nasal drops and sprays

There are also non-drug alternatives such as saline (salt water) nasal sprays and nasal washes (nasal irrigation). Although these products may relieve the symptoms, they usually aren't able to replace medication entirely.

Allergen-specific immunotherapy (also known as desensitization) can reduce your sensitivity to allergens over the long term. Like with vaccines, this treatment approach involves exposing people to small amounts of the allergen. Here it is done at regular intervals by either injecting the allergen under your skin or placing it under your tongue. Allergen-specific immunotherapy takes at least three to five years to complete.

Further information

When people are ill or need medical advice, they usually go to see their family doctor first. You can read about how to find the right doctor in our topic "Health care in Germany" – and our list of questions can help you to prepare for your appointment.

Sources

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• Greiner AN, Hellings PW, Rotiroti G et al. Allergic rhinitis. Lancet 2011; 378(9809): 2112-2122. [PubMed: 21783242]
• Head K, Snidvongs K, Glew S et al. Saline irrigation for allergic rhinitis. Cochrane Database Syst Rev 2018; (6): CD012597. [PMC free article: PMC6513421] [PubMed: 29932206]
• Hoang MP, Chitsuthipakorn W, Seresirikachorn K et al. As-needed intranasal corticosteroid spray for allergic rhinitis: a systematic review and meta-analysis. Rhinology 2022; 60(4): 242-251. [PubMed: 35379997]
• Li CL, Lin HC, Lin CY et al. Effectiveness of Hypertonic Saline Nasal Irrigation for Alleviating Allergic Rhinitis in Children: A Systematic Review and Meta-Analysis. J Clin Med 2019; 8(1): E64.
• Miligkos M, Dakoutrou M, Statha E et al. Newer-generation antihistamines and the risk of adverse events in children: A systematic review. Pediatr Allergy Immunol 2021; 32(7): 1533-1558. [PubMed: 33894089]
• Robert Koch-Institut (RKI). KlimGesundAkt: Aktualisierung des Sachstandsberichts „Klimawandel und Gesundheit“. 2022.
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• Velentza L, Maridaki Z, Blana E et al. Antihistamines in the Management of Pediatric Allergic Rhinitis: A Systematic Review. Paediatr Drugs 2020; 22(6): 673-683. [PubMed: 32936412]

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