Hay fever is also known as seasonal allergic rhinitis. It is an allergic response to pollen (the male component of the plant’s reproductive system). It can also be a response to other microscopic substances that are only present at certain times of the year. Allergic rhinitis can also be present all year round, (perennial).
In the spring, pollinating trees are responsible for causing hay fever. Over the summer, grasses and weeds produce the pollen. And in autumn, weeds are mostly to blame. Hay fever can also be caused when mould releases its reproductive cells, which are known as spores. This occurs, between late March until November, usually peaking in late summer and early autumn.
Hay fever doesn't usually affect children until they're about seven. Older children and teenagers are more susceptible to the allergy than adults.
Find out more about how to treat hay fever