Birch Pollen and Allergies

Towards the end of March we are coming into the birch pollen season, so make sure you are prepared.  Read on to find out more about Birch trees, pollen and its role in Allergy.

The birch tree is one of several species of trees that produce pollen in spring in the UK. Other trees that flower and produce pollen in spring include the Hazel, Alder, Popular, Ash and Oak. However, the sliver birch is considered to be the most allergenic of these species with an estimated 25% of the population in the UK suffering allergy related symptoms.

The weather plays a significant role in the production, distribution and dispersion of pollenBirch pollen, for example, needs moderate to high winds. Sunlight and pollen.

The amount of daylight, or the “photoperiod”, is also crucial to pollen production because of photosynthesis. If there is a particularly cloudy spell of weather then plants and trees will produce less pollen. Tree pollen season occurs first in the pollen calendar, typically from late March to mid-May, (this is then followed by the grass pollen and then weed pollen season.)

Did you know...

  • 25%

    of adults in the UK

    are affected by allergic rhintis

  • 10-15%

    of children in the UK

    are affected by allergic rhinitis

What is the pollen count?

The pollen count is the amount of pollen per cubic metre observed during the past 24 hours which, when combined with weather conditions, provides the pollen forecast.

Hay fever symptoms usually appear when the pollen count exceeds 50. With Birch pollen- a reading between 81 and 200 is high. The MET office keeps track of pollen counts and alert us when it is high.

Worcester pollen count

The University of Worcester has a useful webpage that gives a daily pollen forecast for the UK. Useful Apps to track pollen forecast include Allergy Alert App and My Pollen Forecast UK.

Click here to view Worcester pollen count

Top tips for reducing tree pollen exposure

  • Check pollen forecasts daily and stay indoors wherever possible when the tree pollen count is high. Hay fever symptoms usually appear when the pollencount exceeds 50. Rain washes pollen from the air so counts should be lower on cooler, wet days.
  • Keep car windows closed and the air intake on ‘recirculate’ when driving.
  • Keep windows closed when indoors.
  • Avoid drying clothes/ linen outside when pollen counts are high.
  • On high pollen days, shower and wash your hair and change your clothing, especially before going to bed
  • Wipe pets’ coats with a damp cloth to remove pollens when they have been outside.
  • Wear a mask, wraparound sunglasses and a hat with a large peak or brim when outdoors to keep pollen allergens out of your eyes, face and hair. Wearing a face mask has been shown to reduce symptoms of hay fever, by reducing the amount of pollen we inhale, as well as creating a warm humid environment to breathe in which reduces the reactivity of the nose.

Find out more about Birch trees

Birch trees produce pollen via yellow catkins that hang down from the branches, like other tree pollens, the pollen grains are incredibly small and fine and pollinated by travelling on the wind. Tree pollen can be carried long distances by the wind or even a light breeze, so that you do not need to be in direct contact with birch trees to experience symptoms.

Birch pollen season usually peaks in spring, between April and May, however Birch pollen can cross-react with hazel and alder pollen, so that some tree-pollen sufferers can experience symptoms starting in Winter and lasting until late May or early June. While some people with hay fever react to one type of pollen during the ‘season’, and then feel better later in the year, it is also possible to be affected by more than one type of pollen or airborne allergen, leading to many months of allergic rhinitis symptoms, for example some people have both tree pollen and grass pollen allergy and will experience symptoms for most of the spring and summer.

Birch pollen and gardening

Birch trees have become very popular trees to plant in the street or the garden in the UK. However, birch tree pollen is highly allergenic, and it is advisable to avoid planting birch trees near homes or in school grounds where the pollens can sensitise susceptible people leading to worsening symptoms of allergy including hay fever and asthma.

What are the symptoms I should look out for?

The nose and mouth in the upper airway are the entrance to the lungs (all this is called the respiratory tract in medical terms). Allergens and irritants that are inhaled (breathed in) have the potential to cause allergic symptoms.

Hay fever (The medical name is Allergic rhinitis) is a very common condition caused by inflammation in the lining of the nose that is triggered by an allergen. Symptoms of hay fever often include runny or stuffy nose, sneezing, itchy nose, mouth, ears and throat, itchy watery eyes, coughing.

As well as hay fever or allergic rhinitis symptoms, tree pollens are also known to trigger wheeze or difficulty breathing if you also have allergic asthma, itchy eyes (rhinoconjunctivitis, symptoms of hay fever also affecting the eyes) and pollen food syndrome or oral allergy syndrome.

Most people with allergic rhinitis should be able to manage their symptoms by taking a daily non – sedating antihistamine. Your pharmacist will be able to advise you on the best choice for your individual needs. If your symptoms do not improve using a daily antihistamine or you have worsening symptoms of asthma, then you should seek advice from your GP or practice nurse. Occasionally you may require referral to a specialist for more specialised treatments.

Treatment options

Treatments Medication for allergic rhinitis can be very effective, especially when used correctly. Some medications work by blocking the allergic response (such as antihistamines) and others by reducing inflammation (such as a nasal spray containing corticosteroids, very little steroid gets absorbed into the body, but it acts by reducing the swelling that causes the nasal blockage).

There are a large range of antihistamines in tablet, liquid or nasal spray form. Often a non-sedating daily antihistamine (does not cause drowsiness) may be all that is needed if symptoms are mild, and are most effective for sneezing or an itchy, runny nose.

For symptoms that are more persistent including a blocked or stuffy nose a corticosteroid nasal spray is required to treat the inflammation. These are available from pharmacists or on prescription from your GP. For moderate to severe symptoms, a spray that contains corticosteroid plus antihistamine can now be prescribed by your GP. It is essential to use nasal sprays correctly. So, ask your pharmacist or GP/practice Nurse how to use it). Additional types of medication are required on prescription for people who suffer seasonal asthma as well as hay fever symptoms. Always see your doctor if you have these types of symptoms.

Antihistamines and corticosteroid nasal sprays often control eye symptoms as well, but eye drops are available over-the-counter or on prescription if needed. Cromoglycate drops are often effective, but your GP can prescribe more effective drops for severe allergic eye symptoms.

All rhinitis treatments should be taken regularly as it is more difficult to control symptoms that are already well established. Only taking medications occasionally on the worst days is much less effective and you should aim to start using the preventative/treatment nasal sprays two weeks before your symptoms usually begin.

Allergy testing

Allergy testing is not always required in simple hay fever because the trigger substances can be easily identified from the history of when and where symptoms occur. However, it is needed if the trigger is not obvious or if exact identification is needed for treatment such as immunotherapy. Skin prick test or blood tests (specific IgE to the allergen to be tested) are the correct tests.

Birch pollen and allergy to fruits and vegetables

Birch pollen sensitivity can also cause pollen food syndrome or oral allergy syndrome. This is a hypersensitivity reaction to fruits, vegetables and nuts (often referred to as plant-based foods) usually causing mild irritant symptoms such as itching of the mouth, lips and throat when eaten in their raw form.

If you are susceptible to allergies, you can become sensitised to airborne pollens by breathing them in.  This is most commonly associated with the classic symptoms of hay fever including runny, itchy nose and itchy eyes. With food pollen syndrome many plant-based foods – fruit, vegetables, nuts and cereals, have a protein structure that is very similar to the pollens in trees, grasses and weeds (this is called cross reactivity). However, the immune system doesn’t always recognise the difference between the pollens in the trees, grasses, or weeds that you breathe in and the pollen structure in the plant-based foods that you eat. With pollen food syndrome the immune system recognises the food protein that you eat as an allergen and creates an allergic response.

Pollen food syndrome is usually triggered by eating fresh fruit, raw vegetables and raw nuts. Some people are affected by only one or two foods and others can react to a wide range of foods. The most common foods involved are apples, peaches, kiwi, hazelnuts and almonds, but just about any fruit, vegetable or nut can cause a reaction.

If you have symptoms that are suggestive of pollen food syndrome it is important that you seek advice from a healthcare professional.

Allergy testing

Often your healthcare professional can diagnose pollen food syndrome from your consultation without any need for further testing. However, if your diagnosis is not clear your healthcare professional may recommend that you have a blood test or skin prick testing or prick to prick of the fresh food, where facilities are available.

Management – How do I manage pollen food syndrome?

Avoidance of the foods that cause your reactions is most important, there is no need to avoid foods that do not cause any symptoms. Usually, you will only need to avoid the allergenic food in its raw form as cooking destroys (denatures) the allergens. It is worth trying the food cooked, canned or microwaved to see if it is tolerated. Some people find that different varieties of fruits or vegetables can be tolerated, for example it is worth checking to see whether you can tolerate one type of apple, even if another type causes symptoms.

The majority of cases of food pollen syndrome reactions are mild such as mouth or lip itching or swelling and stopping eating the food and drinking some water may be all you need to do reduce or eliminate the symptoms. The tingling, itching and swelling should settle within 30 minutes to an hour without treatment, but if you are concerned or are having severe or unpleasant symptoms then take a non-sedating antihistamine. If you have taken an antihistamine and feel your symptoms are not improving, then you may need additional treatment and you should seek medical advice. Do not rely on antihistamines or an asthma inhaler if you have a food allergic reaction which affects your breathing or circulation (causing faintness).

If you have symptoms that are suggestive of pollen food syndrome it is important that you seek advice from a healthcare professional.

 

Useful website resources

Allergy UK

ENT UK  

British Dietetic association

This content has been developed by the Allergy UK clinical team and this page is supported by Thermo Fisher Scientific

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