If you suffer from sneezing, a runny nose, or itchy eyes, you might think you have a cold. However, it could be an allergy. When you come across something that you are allergic to, your body reacts by producing chemicals. These chemicals cause the sneezing, runny nose, and itchy eyes.
People can be allergic to many different things, such as:
- Pollen
- Dust mites
- Animal dandruff
- Mold
- Foods
- Drugs.
Hay fever is also known as
pollen allergy, and is a type of seasonal allergic rhinitis (runny nose).
Hay fever is one of the most common kinds of
allergies. About 35 million Americans suffer from hay fever. Pollen is made by trees, grasses, and weeds. During the spring, summer, and fall, some plants release pollen into the air you breathe. Your symptoms might be different at different times of the year, depending on the kinds of plants that grow where you live and what allergies you have.
The types of pollen that most commonly cause allergic reactions are produced by the plain-looking plants (trees, grasses, and weeds) that do not have showy flowers. These plants make small, light, dry pollen grains that are custom-made for wind transport.
Amazingly, scientists have collected samples of ragweed pollen 400 miles out at sea and 2 miles high in the air. Because airborne pollen can drift for many miles, it does little good to rid an area of an offending plant. In addition, most allergenic pollen comes from plants that produce it in huge quantities. For example, a single ragweed plant can generate a million grains of pollen a day.
Common hay fever symptoms can include:
- Sneezing
- Running or stuffy nose
- Coughing
- Itchy eyes, nose, and throat
- Watery eyes
- Red, swollen eyes.
There are several tests your doctor can recommend if he or she suspects hay fever:
Both tests look for certain disease-fighting cells (called antibodies). Your body makes these cells to match whatever it is fighting, and this tells doctors what you are allergic to.
Skin Tests
Your doctor may also use a needle to put a small amount of allergen into your skin. After a few minutes, the reaction tells your doctor if you have
allergies.
Blood Tests
Your doctor may use a blood test to look for a protein in your blood called IgE. This protein is made by people with allergies and hay fever. It also helps fight certain types of infection.
Treatment Options for Hay Fever
Your doctor can help you decide what to do for your hay fever. Some hay fever treatment options can include:
- Avoiding the things that cause your symptoms
- Using medicines
- Getting allergy shots.
Allergy shots contain small amounts of what you are allergic to. At first, shots may be given every week to lessen your symptoms. The shots are usually continued for three to five years.
You can distinguish symptoms of hay fever from those of a cold, because a cold tends to be short-lived, results in thicker nasal secretions, and is usually associated with sore throat, hoarseness, fatigue, and fever.
The following table explains typical differences between hay fever and a cold.
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|
Hay Fever
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Colds
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Signs
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Running or stuffy nose, sneezing, wheezing, itchy and watery eyes
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Fever, aches and pains, stuffed nose, sneezing, and watery eyes
|
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Warning Time
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Symptoms begin right away
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Symptoms usually take a few days to start
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Duration
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Symptoms last as long as you are around the allergen
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Symptoms often go away within a week
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Types of Pollen That Cause Hay Fever
The type of allergens in the pollen is the main factor that determines whether the pollen is likely to cause hay fever. For example, pine tree pollen is produced in large amounts by a common tree, which would make it a good candidate for causing a
pollen allergy. It is, however, a relatively rare cause of pollen allergy, because the type of allergens in pine pollen appears to make it less allergenic.
Among North American plants, weeds are the most proli?c producers of allergenic pollen. Ragweed is the major culprit, but other important sources are:
- Sagebrush
- Redroot pigweed
- Lamb's quarters
- Russian thistle (tumbleweed)
- English plantain.
Grasses and trees, too, are important sources of allergenic pollens. Although more than 1,000 species of grass grow in North America, only a few produce highly allergenic pollen.
It is common to hear people say they are allergic to colorful or scented flowers, like roses. In fact, only florists, gardeners, and others who have prolonged, close contact with flowers are likely to be sensitive to pollen from these plants. Most people have little contact with the large, heavy, waxy pollen grains of such flowering plants, because this type of pollen is not carried by wind, but by insects such as butterflies and bees.
Some grasses that produce pollen include:
- Timothy grass
- Kentucky bluegrass
- Johnson grass
- Bermuda grass
- Redtop grass
- Orchard grass
- Sweet vernal grass.
Some trees that produce pollen include:
- Oak
- Ash
- Elm
- Hickory
- Pecan
- Box elder
- Mountain cedar.
When Do Plants Make Pollen?
One of the most obvious features of
pollen allergy is its seasonal nature: People have symptoms of hayfever only when the pollen grains to which they are allergic are in the air. Each plant has a pollinating period that is more or less the same from year to year. Exactly when a plant starts to pollinate seems to depend on the relative length of night and day (and, therefore, on geographical location) rather than on the weather. On the other hand, weather conditions during pollination can affect the amount of pollen that is produced and distributed in a speci?c year. Thus, in the Northern Hemisphere, the farther north you go, the later the start of the pollinating period and the later the start of the pollen allergy season.
A pollen count, familiar to many people from local weather reports, is a measure of how much pollen is in the air. This count represents the concentration of all the pollen (or of one particular type, like ragweed) in the air in a certain area at a speci?c time. It is shown in grains of pollen per square meter of air collected over 24 hours. Pollen counts tend to be the highest early in the morning on warm, dry, breezy days and lowest during chilly, wet periods. Although the pollen count is an approximate measure that changes, it is useful as a general guide for when it may be wise to stay indoors and avoid contact with the pollen.
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