Overview
Hay fever affects the nose, sinuses (small air-filled cavities behind your cheekbones and forehead), throat and eyes. It causes:
* sneezing,
* a runny nose, and
* itchy eyes.
Hay fever usually occurs in spring and summer, when there is more pollen in the air. Trees, grass and plants release pollen as part of their reproductive process. Mould and fungi also release tiny reproductive particles, called spores.
People with hay fever can experience their symptoms at different times of the year, depending on which pollens or spores they are allergic to.
Allergic rhinitis can be classified as either intermittent or persistent, depending on how often people experience their symptoms.
Allergic Reaction
The symptoms of hay fever occur when the immune system (the body’s defence system) overreacts to a normally harmless substance, in this case pollen. When the body comes into contact with pollen, cells in the lining of the nose, mouth and eyes release a chemical called histamine. This triggers the symptoms of an allergic reaction.
How common is it?
Hay fever is a common condition that affects around 20% of people in the UK/Ireland. Hay fever is more likely if there is a family history of allergies, particularly asthma or eczema.
Outlook
Hay fever cannot be cured completely, but there are a number of treatments available to relieve the symptoms. These include antihistamine tablets, nasal (nose) sprays and eye drops. Some can only be prescribed by a GP, but many are available over-the-counter (OTC) in pharmacies.
For persistent hay fever, a treatment known as immunotherapy can be used to gradually increase a person’s exposure to the allergen while monitoring their response. This can be effective at reducing the severity of an allergic reaction, but is not suitable for everyone.
Hay fever affects between 15 and 20% of the population and is mainly caused by grass pollen.
Hay fever, or seasonal allergic rhinitis, is an allergy caused by the body making antibodies to certain triggers, such as pollen.
Although it's more common in children, and particularly teenagers, you can develop hay fever at any time.
Once your body has made the antibodies, the next time you’re in contact with the pollen, chemicals including histamine are released which produce the symptoms of hay fever. These symptoms usually include sneezing and itchy, watery eyes.
As well as histamine, there are other chemicals released that produce more delayed symptoms of hay fever, such as swelling and stuffiness.
What causes it?
In Ireland, Hay fever is mainly caused by grass pollen but increasingly, tree and shrub pollen, mould spores and weeds cause it too.
The pollens that cause hay fever vary from person to person and region to region. The amount of pollen in the air will also affect how bad your hay fever is.
There's more likely to be more pollen in the air on hot, dry and windy days than on cool, damp, rainy days. Research shows that pollution, such as cigarette smoke or car exhaust fumes, also makes some allergies worse.
The time of year at which people begin to experience hay fever symptoms varies depending on the types of pollen they're allergic to. Trees start to release their pollen in April, grasses in mid-June, and weeds and certain shrubs in late summer.
So hay fever season can last from April to October, and some people could have symptoms as early as March. They would only have two or three months off in the winter and then the cycle starts all over again.
How can you reduce the risk of getting hay fever?
If you live in Ireland, you've got around a 20% chance of developing hay fever. If your parents are allergic to something, you have a 50% chance of inheriting an allergy (it doesn’t have to be the same allergy).
If you smoke while pregnant, your child could be more likely to develop an allergy. Not smoking and eating a healthy diet can limit the chances of passing on the tendency to your children.
Other tips
Avoiding exposure to pollen is the best way to reduce the allergic symptoms associated with hay fever. Limit exposure to pollens by keeping the windows shut at night and first thing in the morning, staying indoors when the pollen count is high (between 50-150), wearing wraparound sunglasses, or putting some Vaseline just inside your nostrils, which will trap some of the pollen.
Don't mow the grass or sit in fields or large areas of grass. Wash your hands and face regularly. Avoid exposure to other allergens, such as pet fur, or environmental irritants, such as insect sprays or tobacco smoke.
Treatment
As with most allergies, the best way to control hay fever is to avoid triggers. However, it's difficult to avoid pollen, particularly during the summer.
Even straightforward hay fever can be debilitating, causing runny eyes, sleepless nights, bunged-up nose and headaches. Some people with hay fever develop asthma.
A range of over-the-counter products is available to treat the symptoms of hay fever, including tablets, nasal sprays, eye drops and creams.
Antihistamines are the usual treatment for the main symptoms, such as itchy, watery eyes and runny nose, while steroid nasal sprays are the main treatment for a stuffy nose.
Speak to your GP or pharmacist before you decide on a treatment. It's particularly important to speak to your GP if you have asthma. Hay fever often makes asthma symptoms worse. If this happens, you may need to increase the dosage of your asthma medication.