Hay fever is a common allergic condition that affects many people at some point in their life.

Hay fever is caused by breathing in pollen particles and by pollen getting into the eyes. You can get hay fever at any time from early spring to late summer, depending on which pollen or pollens you're allergic to.

The pollens most likely to cause problems in early spring are those from trees such as the silver birch, ash, and oak .

Grasses pollinate during mid-summer from May to August. The most profusely pollinating grasses are timothy, rye, cocksfoot, meadow and fescue.

Occasionally, in late summer and autumn, weeds such as nettles and dock as well as mugwort and plantain can trigger hay fever.

The condition tends to occur in atopic allergy-prone families and usually starts in the early teens, with symptoms peaking in the mid 20s.

The main symptoms of hay fever are:

* Repeated sneezing attacks
* Runny or itchy nose
* Itchy or watery eyes
* Itchy throat, palate and ears
* Loss of concentration
* General feeling of being unwell (hence 'fever')

If the pollen count is very high, many will also wheeze (so-c