The Australasian Society of Clinical Immunology and Allergy

SEPTEMBER 2001 - TOPIC OF THE MONTH

Allergies to pollen from grasses, weeds or trees can cause symptoms of hay fever (allergic rhinitis) and asthma. Pollen seasons can last for up to several months of each year and it can therefore be difficult to avoid exposure.

A new POLLEN CALENDAR on the ASCIA website @ www.allergy.org.au can help identify plants in each state of Australia and pollination times. This can assist with diagnosis and choice of treatment options such as avoidance, medication or immunotherapy, to prevent or treat symptoms.

WHAT IS POLLEN?

Pollen is produced by plants to fertilise the female flower, in order to reproduce plant species.

• Some plant species (mainly highly flowered plants such as wattle) produce small amounts of pollen which are distributed by birds and bees from one plant to another and only occasionally trigger allergies.
• Other plant species which tend to have less brightly coloured flowers (such as grasses, weeds and some trees) rely on airborne pollination and therefore produce larger amounts of pollen, which trigger allergies.

POLLEN ALLERGY CAUSES HAYFEVER AND ASTHMA

Although the common name for Allergic Rhinitis is Hayfever, it is pollen and not hay that causes symptoms, which include:

• running, itching and often blocking of the nose;
• itchy and running red eyes;
• itchy ears, throat and palate; and
• extreme fatigue, which causes considerable impairment of quality of life and productivity.

In many cases, if hayfever symptoms are not treated early, an asthma attack will follow.

As shown on the POLLEN CALENDAR, pollen seasons can last for several months, so symptoms may not just occur in Spring. Thunderstorms or changes in weather during pollen seasons can also trigger asthma attacks.

DIAGNOSIS IS IMPORTANT

A careful history should be taken of the timing of symptoms and whether relief is obtained by going away on holiday. It is also important to identify plants that grow in your area (the POLLEN CALENDAR may help).

Allergy tests (skin prick tests and/or blood [RAST] tests) can be used to confirm the diagnosis using appropriate pollen allergens and results should be interpreted by a doctor trained in allergy, in conjunction with the history.

EFFECTIVE TREATMENT OPTIONS ARE AVAILABLE

• Avoidance measures should be taken (where possible) such as staying indoors on windy days and planting a low allergen garden around the home.
• Medications such as antihistamines or corticosteroid nasal sprays are helpful if started early in the spring. Vasoconstrictor nasal sprays should not be used for more than a few days, as there are long term ill effects.
• Pollen sensitive asthmatics will almost certainly need to increase their preventive asthma medications during pollen seasons.
• Allergen immunotherapy, commonly called desensitising injections, can be very effective in the long term. Advice regarding such treatment can be gained from a specialist in allergy or clinical immunology.

Further information on pollen allergy, hayfever, immunotherapy and
thunderstorm asthma is available @

http://www.allergy.org.au