Hay Fever

What is hay fever?

Hay fever is usually an allergic reaction to pollens of trees, grasses, and weeds. Sometimes it is an allergy to mold spores. Hay fever may occur any time of the year. It generally occurs in the spring, summer, or fall. Hay fever is also called seasonal allergic rhinitis.

How does it occur?

Allergic symptoms result from reactions of your body to substances that it sees as foreign. Substances that cause an allergic reaction are called allergens.

The allergens that cause hay fever are pollen and mold. They float in the air and are spread by the wind. The type of pollen in the air depends on the growing season and area of the country. Tree pollens cause most spring hay fever. In the summer, grass and some weed pollens are usually the cause. From late summer to the first frost, other weed pollens cause hay fever.

The parts of the body that may be affected by hay fever are the eyes; the lining tissue of the nose, sinuses, and eustachian tube (which connects the middle ear with the back of the throat); and, less often, the lungs. When the pollen or molds come into contact with these tissues in an allergic person, cells in the tissues release a chemical called histamine. Histamine causes the tissues to itch, swell, and produce more mucus or tears than is normal.

As many as 1 in 10 people suffer from hay fever at some time in their lives. Hay fever is more common in people with other allergies such as asthma or eczema. Hay fever tends to run in families.

What are the symptoms?

Common symptoms of hay fever are:

Other symptoms are:

How is it diagnosed?

Your health care provider will ask about your history of symptoms. If your symptoms occur just in certain seasons, your health care provider will suspect that you have hay fever. A check of your ears, nose, throat, and lungs may confirm the diagnosis.

You may have tests for specific allergies. For most people the best tests are skin scratch or prick tests. For these tests a health care provider places tiny amounts of suspected allergens under your skin and looks for reactions. These allergy tests may find which allergens are causing your symptoms. In some cases you may have blood tests to look for antibodies to suspected allergens.

How is it treated?

Once you know what you are allergic to, you can try to avoid the allergens. For example, using an air conditioner rather than an attic fan lessens the amount of pollen that gets into your home.

Many hay fever symptoms are so mild that they need no treatment. Or you may just need to take a nonprescription medicine once in a while. If you need further treatment, a variety of medicines are available, such as decongestants, antihistamines, and steroid nasal sprays.

Decongestants shrink the swollen lining tissues of the ear, nose, and sinuses. Possible side effects of decongestants are trouble sleeping, rapid heart rate, and elevated blood pressure.

Antihistamines fight the effects of histamine on your tissues. You may need to take these medicines only when your symptoms are bothering you. In more severe cases, you might take them daily during your allergy season(s) to prevent symptoms.

There are different types of antihistamines. Drowsiness is a common side effect of many antihistamines. This may not be a problem if a dose at bedtime is all you need. Or you might try the medicine for several days despite the drowsiness. Often the drowsiness goes away after you have taken the drug for 3 to 5 days. Some "nonsedating" antihistamines are available that usually don't cause drowsiness. They work well for most people, but they tend to cost more than other antihistamines.

It is safe to take both antihistamines and decongestants together as long as you have no other reason for not taking them.

If antihistamines do not help eye symptoms caused by your allergy, your health care provider may prescribe eye drops.

Prescription nose sprays are very effective in preventing or minimizing nasal and sinus congestion, runny nose, and postnasal drainage. Two types of sprays are available: steroid and cromolyn. They work best to relieve symptoms if you use them on a regular basis during the allergy season.

Nonprescription nasal sprays, after several days of use, may actually make nasal congestion worse. These are not recommended.

Symptoms that affect your breathing are treated with medicines used to treat asthma, such as quick-acting, inhaled bronchodilators to treat symptoms and other types of inhaled medicines to prevent symptoms.

If your symptoms bother you a lot despite medicines or if you often have complications, such as ear or sinus infections or asthma attacks, your health care provider may suggest allergy shots. A mixture is prepared that contains the allergens identified in your allergy tests. The mixture is injected into your skin in tiny but increasing amounts over the course of many months. Over time, the shots make you less sensitive to the allergens. Usually 4 to 6 months of allergy shots give relief from the allergies. You may need to continue the shots for 2 to 3 years or longer.

How long will the effects last?

Allergies last different amounts of time for each person. Allergies can develop at any age. Children with hay fever may continue to have seasonal allergies as they grow older or the allergies may go away over time. If you start having allergies as an adult, you will probably continue to have them. However, the allergies may stop if you move to an area where the substances causing your allergies are not present.

How can I help myself?

What can be done to help prevent hay fever?

There is no known way to prevent allergies. However, some doctors think that breast-fed babies may be less likely to develop allergies. Also, if your family has a very strong history of allergies, you might try to avoid your family's most common allergens. For example, you might need to stay away from cats. This might help stop you from having severe symptoms.

This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.

Back to Learning Main Site