Allergy to pollen

The number of people affected by hay fever (allergy to pollen) is on the increase

  • Allergy to pollen affects many people of all ages.
  • There is a prevalence among adolescents and young adults, however, children as young as 2 have consulted an allergy specialist.
  • Also, patients as old 75 without any past history of allergy have experienced hay fever symptoms.

Conditions for pollen to cause allergic reactions

  • Pollen is released by plants into the atmosphere to allow fertilisation.
  • For pollens to cause an allergic reaction they must be small particles, in large amounts, have a strong allergenic component and be easily transported in the wind, and can travel up to several hundreds of miles.
  • Pollens transported by insects, is called entomophilous and plays a secondary role in triggering allergies.

Allergic symptoms caused by pollens

  • Rhinitis (runny nose) predominantly affects patients with hay fever, usually the same symptoms at the same time each year: itchy nose, violent repetitive sneezes, persistent runny discharging nose and a blocked nose.
  • Watery, itchy, red eye symptoms, very often accompany allergic rhinitis.
  • Itchy mouth, nose and even ears are experienced.


Hay fever sufferers commonly have asthma symptoms.
  • Tree pollens, in particular 'birch' are problematic and cause a high pollen count.
  • It is becoming apparent that more people that have never experienced an allergic reaction are now doing so and presenting with sneezing and coughing episodes.

As many as 1 in 2 hay fever sufferers experience episodes of coughing, breathlessness and wheezing. These symptoms are characteristic of asthma, however, patients do not always realise that these are symptoms of asthma and do not seek help or treatment.


Hay fever is frequently accompanied by periods of exhaustion. People are debilitated in their daily life both at work and at home. Sleep is commonly affected, and the enjoyment of being outdoors is removed, often feeling restricted for 2 to 3 months of the year.

It is important to see your GP and get the appropriate treatment so that a normal life can be resumed and enjoyed. Symptoms left untreated can also have consequences especially where asthma symptoms are concerned.

The pollen seasons

Various types of pollens are released each in turn in the atmosphere from January to October.

The season of tree pollens

This first season begins
Cypresses, plane trees and birch are the trees, which cause the most allergic symptoms.
Cypress pollens cause a so-called green pollution.
Trees such as the birch, the poplar and ash are responsible for many pollens.
Main tree pollens
  • Cupressaceae: cypress, thuja
  • Oleaceae: ash, olive-tree
  • Platanaceae: plane tree
  • Betulaceae: birch, charms, alder, hazel tree
  • Fagales : oak, chestnut tree
  • Salicaceae : poplar, willow
  • The Tiliaceae: limetree

The season of grass pollens

Grass pollens, traditionally called "hay fever" are where the grasses pollinate.
  • It lasts approximately two months.
  • Grasses grow everywhere, in meadows, ditches, in forests, on roadsides, gardens, in the countryside but also in the cities.
  • In other countries where there are mountains there is a later pollen season. The pollen count is at its highest in July and August after the ice and snow has melted. Sufferers are best to avoid taking a holiday here at this time..

List of principal grass pollens:
  • Graminaceous fodder: dactyl, phleum, ryegrass, meadow grass, fescue, couch grass.
  • Graminaceous cereal: wheat, corn, barley, oat, rye.

Season of herbaceous pollens

  • Even later, from the end of summer to October herbaceous plants, which there approximately 50.000 species, spread out in towns, on the edge of the roads or on paths.
  • Ragweed, is the most well known one and proliferates at the end of August and beginning of September.
    • It causes very debilitating episodes of allergic rhinitis and asthma.

Pollens are real biological pollutants: green pollution

  • The presence of significant amounts of allergic pollens in an area can cause a biological form of pollution, still called green pollution.
  • Some pollens, like cypress and ragweed, cause symptoms not only in people with an atopic (allergic) background, but based on a threshold of toxicity, the concentration of pollen grains in the atmosphere affect many non allergic people.

The examples of pollution pollens

  • Not so much in the UK, but on the Mediterranean, Cypress trees are planted in large amounts as hedges as they are easy to grow and inexpensive to buy. As a result they impact greatly on those sufferers.
  • Ragweed
  • Ragweed is a herbaceous
  • Its pollens are very volatile and can spread over more than 150 kilometers.
  • It develops on empty and badly maintained grounds, on building sites, roadsides like fallow grounds.
  • How to avoid the ragweed proliferation?
    • Uprooting and mowing must be done before the blossoming date, usually in July.
    • Establishing a fallow land could avoid grass proliferating.

The influence of pollution and global warming

Climatic conditions

  • The intensity of pollination varies from year to year according to meteorological conditions and the local area.
  • Climatic conditions are crucial:
    • Heat and moisture increase the concentrations of pollens.
    • Cold, dryness, or heavy rains decrease them.
    • The sun and wind disseminate pollen grains.


  • The development of pollen allergies over the last thirty years has been parallel to an increase in chemical pollution.
  • Urban pollution worsens the toxicity of pollens by weakening the surface structure of the grains and by allowing the release of allergen proteins.
  • Pollutants are also irritating factors which cause an increase in the bronchial, nasal and ocular hyper-responsiveness.

Global warming

Experts agree that milder winters and hotter summers have lengthened and intensified the hay fever season.

Cross-allergies between pollens and food

In certain cases, people allergic to pollens may have an itchy mouth, and even an oedema from eating certain fruits and raw vegetables: it is a cross-allergy between food and pollens. For example a patient allergic to birch pollen will not be able to eat apples because of a terrible mouth and throat itching.

Examples of cross-allergies
  • POLLENS of GRAMINACEOUS PLANTS ( herbaceous plants, grasses, herbs): tomatoes, sweet peppers, potatoes, melon, kiwi, wheat flour
  • RAGWEED POLLENS: melon, banana, watermelon
  • MUGWORT POLLENS: dill, carrot, fennel, parsley, celery, coriander
  • POLLENS OF HAZEL TREES: nut, hazel nut
  • POLLENS Of ALDERS: peach, hazel nut, cherries, almond, parsley, apples, pears.
  • BIRCH POLLENS: the most frequent cross-allergies
    • Apple: the most widespread cross-allergy
    • Peach, pear, almond, cherry, nectarine, apricot, nut,
    • Celery
    • Kiwi

It may be necessary to consult with an allergy specialist before eating some of these fruits as there is risk of a severe allergic reaction.

Self management of pollen allergy

There are some simple measures you can take to reduce your allergy symptoms;
  • Rinse your hair in the evening before going to bed in order to avoid the pollens which have accumulated throughout the day settling on pillows and causing allergic symptoms.
  • Wear sunglasses and a hat when outside.
  • Avoid rubbing your eyes
  • Avoid mowing the lawn
  • Ventilate your bedroom early in the morning
  • Avoid smoking as it worsens allergic reactions
  • Avoid swimming as the chlorine used in swimming pools irritates the mucous membranes of the nose and the eyes
  • Avoid drying linen outdoors
  • Wear a mask when gardening
  • Drive with closed windows.
  • It is advisable for students with a pollen allergy to see their GP before sitting exams. Good planning and management is crucial to avoid debilitating symptoms.
  • Think about where you book your holidays, the sea side has lower pollen

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