This year the National Pollen Research Unit forecasts that pollen count levels are five times higher than last year. Dr. Howard Lee advises how parents can combat hay fever

Most people look forward to the warm and sunny weather, but there are many - and it is thought that in Britain this means about ten million people - who do not; spring heralds for them months of violent sneezing with itchy, sore eyes.

What is hay fever?
Hay fever - seasonal allergic rhinitis - is usually related to temporary environmental allergens such as pollens and spores. It is the commonest allergic condition in most communities, affecting anywhere from 20 to 30 per cent of the population, and it is said to be the commonest allergic disorder on a worldwide basis.

The symptoms and signs are the same in perennial allergic rhinitis cases, which can be a year-long problem, but these are related to the house dust mite or pets.

How are children affected?
Infants and children, mostly over the age of five, are particularly affected by the consequences of hay fever. Nasal obstruction often leads to poor concentration, hearing difficulties, a cough that may be worse at night and in the morning, poor appetite and growth and disturbed sleeping patterns - like having a permanent 'head cold'. As about a third of people affected develop it before the age of ten, this involves a lot of children. Allergies run in families, and are more common in children who have asthma or eczema. It is also more common to see the problem in children that are exposed to second-hand smoke, air pollution and pets.

Symptoms
Inflammation of the lining of the nose (rhinitis) is the commonest feature, because the inhaled allergens (pollens, etc) are trapped by the natural mucus and filter system of the nose. This reaction encourages the release of a chemical (histamine), which then causes more blocking by swelling the nose linings. A continued exposure to these pollen-allergens alters the nasal sensitivity, so that eventually even smaller quantities of the same allergens can cause ongoing symptoms.

Sneezing is a very prominent feature, accompanied by itching and watery eyes - as well as, on occasions, photophobia (intolerance of light) and intense itching of the nose.

Causes
Grass pollens and some tree pollens are the major cause of this irritation, and there are recognised main and peak periods of pollen release:

• February: birch pollen.
• March/April: hazel, yew and alder.
• June/August and later: grasses, nettle and dock.

Do's and don'ts for parents
Do:

• Keep windows closed at night.
• Try to minimise early morning outdoor activities (most pollen is released before 10am).
• Keep car windows closed, and use 're-circulated' rather than 'fresh' air when travelling.
• Limit outside activity when humidity is high or there is wind.
• Take beach holidays, preferably during the height of the pollen season - here the onshore breeze during the day will keep pollens inland.
• Try to avoid farms and orchards.

• Allow play around freshly mown lawns; this disturbs the contained pollens and moulds.
• Allow play with fallen, raked leaves - for the same reason.
• Don't use bed linen that has been dried on an outside line - pollens and moulds may well have collected on these.

Diagnosis and treatmentParents of a child with symptoms often make the diagnosis, but treatments - because there are so many of them - can be more difficult to choose. It is very important to use any purchased or prescribed treatment efficiently, because uncontrolled allergies can put your child at risk of getting a secondary sinus and/or ear infection.

Seasonal allergies will usually respond well to treatment if certain rules are followed:

• There must be frequent (often four times a day) dosages for some agents.
• They must be used before your child's allergy season begins.
• They must be continued every day throughout the season, especially when improvement is shown.

Forms of treatment

• Antihistamines The newer, non-sedating ones have been a great advance in this form of treatment in recent years - especially as children face examinations at school in the height of the hay fever season. Many of the newer ones are used as a once-daily dosage.

• Topical (locally applied) antihistamines These may be in the form of aerosol sprays or pump-action sprays (the latter is often the best form for children) and are particularly effective in producing rapid relief of itching, sneezing and nasal discharge. They do not have any effect on nasal blocking.
• Special 'anti-allergens' These are chemicals usually administered as nose drops or as a nasal spray and are particularly effective in children - especially when used three times a day. Eye drops are also available.
• Topical (locally applied) steroids The use of intranasal topical steroid nasal sprays has been a significant advance in the treatment of hay fever.
• Decongestant sprays and drops These should only be used with caution and for short periods because overuse can cause worsening problems. Always seek advice first.
• Desensitisation or immunotherapy This is a type of immunisation where a doctor injects a tiny amount of the things that cause the allergies. This type of treatment lost favour in the 1980s in the UK, when the Committee on Safety of Medicines drew attention to serious reactions associated with the treatment. It is, however, very effective - and the position of immunotherapy is now being re-evaluated.