U.S. flag

An official website of the United States government

NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.

InformedHealth.org [Internet]. Cologne, Germany: Institute for Quality and Efficiency in Health Care (IQWiG); 2006-.

Cover of InformedHealth.org

InformedHealth.org [Internet].

Show details

Hay fever: Overview

Last Update: April 23, 2020; Next update: 2023.


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.


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:

Plant Pollen season
Hazel tree February
Alder tree March
Birch tree April
Beech tree May
Oak tree May
Ash tree Mid-April to mid-May
Grasses Mid-May to mid-August
Mugwort Mid-July to late August
Ragweed September

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.


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.


It's 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.


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 about three years to complete.

Further information

When people are ill or need medical advice, they usually go to see their family doctor first. Read about how to find the right doctor, how to prepare for the appointment and what to remember.


© IQWiG (Institute for Quality and Efficiency in Health Care)
Bookshelf ID: NBK279488


Informed Health Links

Related information

  • PMC
    PubMed Central citations
  • PubMed
    Links to PubMed

Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...