Hay fever plants in Wales

Ragweed
Ragweed
Birch
Birch

by Lois Roberts & Tim Rich.

What is Hay fever?

Our bodies defend themselves from various viruses, bacteria and foreign bodies that attack us every day. Some of these will cause our bodies to over-react to a particular substance, causing an allergic reaction. The side-effects of these allergic reactions may be sneezing, rashes or even stomach aches.

Hay fever is caused by an allergic reaction to pollen and this is one of the commonest allergies. It is not a serious medical condition, but is a nuisance to anyone who is affected, and in some cases prevents activities of day-to-day life.

Pollen is carried by the wind and insects, and therefore some is in the air around us. It gets in people's eyes and lands on the membranes in the nose and throat when we breathe. In people susceptible to hay fever, an allergic reaction starts when the body detects allergens, which are chemicals in the pollen grains. The allergic reaction causes inflammation and irritation by releasing another chemical called histamine, which causes the hay fever symptoms such as sneezing and watering eyes.

Hay fever is a common complaint and affects 10-20% of the population at some stage in their lives, but not all sufferers are allergic to all pollens. Hay fever tends to be passed down genetically through families. It is commonest in young people and most likely to start in their teenage years. As people get older, the allergy will usually decline, and very rarely it may start in old age. Most people would have grown out of it by middle age.

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