Avoiding allergens is considered the most effective way to improve allergy symptoms. If doubt exists about which substances trigger allergic reactions, allergy testing can be performed. Treatment with more powerful medications is typically necessary if allergy triggers cannot be entirely avoided.

Airborne pollen from trees and grasses tend to be more abundant during the daytime between 4 AM to 9 PM, when the winds that lift the pollen into the air are brisk. Using air conditioning, if possible, and keeping the windows closed (especially during the day) during allergy season can keep exposure to pollen to a minimum..

Dust mite allergies tend to be worse in the summer when there is more moisture in the air and this allergy can sometimes be confused with hay fever.

The ARIA report, published by the American Academy of Allergy, Asthma, and Immunology and the World Health Organization, documents a strong relationship between allergy-causing substances and asthma. There is even some evidence to suggest that long-term exposure to allergens may actually cause asthma in children, and avoidance of these allergens may prevent asthma from developing. Because of this emerging data, some experts recommend allergy testing in children with hay fever and other allergies to assess whether avoidable allergy-triggering substances such as dust-mites might be contributing to the problem.

The combination of nasally-inhaled steroids and antihistamines is recommended for moderate to severe hay fever by several national and international guidelines (The American Academy of Allergy, Asthma and Immunology, The World Health Organization Guidelines, and the European Academy of Allergology and Clinical Immunology guidelines).

See below for more information about each type of drug.

Nasal steroid inhalers are the most effective treatment available for hay fever. They are very effective for clearing a congested (stuffy) nose, and for sneezing but do not provide as much relief for itching eyes.

Numerous studies have concluded that steroids are superior to antihistamines for alleviating hay fever symptoms (except for the nose and eye itching, for which antihistamines are more effective).

Inhaled steroids are not rapid-acting and can take up to 3 to 10 days to provide maximum relief.

The most common side effects of inhaled steroids include irritation to the nose, nosebleeds, headache and irritated throat. These medications can cause significant irritation to the nasal passages in some people.<

One study raised questions about whether inhaled steroids impact the growth of bones in children. Further investigation is necessary to evaluate whether or not this may occur. Many experts continue to recommend inhaled steroids for children (over 3 years old) while others prefer cromolyn.

Experts recommend starting inhaled steroids 2 to 4 weeks before the beginning of allergy season, and continuing them until the allergy season is over.

Antihistamines are effective for relieving sneezing, and itching eyes and nose, but do not clear up nasal congestion (stuffed nose).

The newer antihistamines are much less apt to cause drowsiness than the older antihistamines (benedryl, Clor-trimeton, brompheniramine, etc) and, therefore, are currently a much more popular choice. However, in some people, drowsiness can still be a problem, so the first few doses should not be taken if driving or operating a machine is necessary.

Claritin and Zyrtec are the only newer antihistamines that are available over-the-counter. They work for some people, but not for everyone. Other newer antihistamines are available as prescription medications and may be prescribed if Claritin does not provide relief.

Zyrtec, azelastine and cetirizine can cause drowsiness in some people, while Allegra/fexofenadine, Claritin/loratadine, and desloratadine are not likely to cause drowsiness.

The newer antihistamines tend to be more expensive than the older ones. To cut costs, hay fever sufferers sometimes take the less expensive, older antihistamines before bedtime, when drowsiness may be acceptable and use the more expensive medications during the daytime.

Studies suggest that antihistamines are not as effective as inhaled steroids, except for nasal and eye itch, for which they are more effective. Antihistamines are more effective than cromolyn.

Combination drugs are available that contain both antihistamines (for relief of itchy eyes and sneezing) and decongestants (for relief of a stuffy nose). There is evidence to suggest that the combination of the two drugs is more effective for hay fever symptoms relief than either type of drug alone.

Over-the-counter combination drugs are available but they contain the older type of antihistamines that can cause drowsiness. Combination drugs that contain the newer antihistamines that do not cause drowsiness are only available by prescription.

One of the ingredients of over-the-counter combination drugs, pseudoephedrine/sudafed, is used to manufacture an illegal substance called "crystal amphetamine" and therefore requires a signature at the pharmacy during purchase.

Decongestants are medications that relieve nasal congestion but have less affect on itchy eyes and sneezing. Antihistamines on the other hand, relieve itchy eyes and sneezing but don't address the stuffy nose as well (except for the antihistamine desloratadine - under the brand names NeoClarityn, Claramax, Clarinex and Aerius - which improves both types of symptoms).

Nasal spray decongestants, such as Afrin, are recommended for no more than a few days in a row. Longer use can cause damage to the lining of the nasal passages.

The decongestant, pseudoephedrine should be used with caution in people with high blood pressure or heart disease, as well as in elderly individuals and children.

Cromolyn is a medication given by nasal spray that is often used to treat asthma and allergies, especially in children. Studies indicate that cromolyn is effective for reducing hay fever symptoms but not as effective as inhaled steroids or antihistamines.

Cromolyn is best suited for mild hay fever and is not usually effective for moderate to severe hay fever, especially if there is significant nasal congestion.

Cromolyn causes very few side effects and is considered safe, even for children as young as 3 years old.

The most common side effects of cromolyn include irritation to the nose, headache and nasal congestion.

Antihistamines are effective for hay fever treatment. They tend to improve symptoms of itching eyes and nose, and sneezing but have less impact on a stuffy nose. Many people with hay fever choose the newer antihistamines because they are less likely to cause drowsiness.

The older antihistamines frequently cause side effects. Drowsiness is one of the most troubling. Studies have shown that drowsiness due to the older antihistamines decreases work productivity, driving ability and increase the chances of accidents.

One study found that drowsiness from antihistamines was the leading cause of work accidents, with higher rates of burns, open wounds, fractures and other injuries. The drowsiness caused by taking antihistamines at nighttime last well into the next day.

Studies suggest that antihistamines are not as effective as inhaled steroids, except for nose and eye itching, for which they are more effective. Antihistamines are more effective than cromolyn.

Allergy shots can be highly effective but should only be used for individuals with severe hay fever that fails to improve despite adequate avoidance of allergens (substances that produce an allergic reaction) and appropriate medications.

Allergy shots are only effective if the right type and dose are given, and should be administered by a highly experienced physician.

Allergy shots can cause a severe allergic reaction and should only be administered in a setting that is equipped to handle those reactions.

Severe allergic reactions with allergy shots are more common in people with asthma and extreme caution should be used if individuals with asthma receive allergy shots.

Leukotrienes are a type of medication that is usually used to treat asthma. Modestly effective at clearing a stuffy nose. Studies suggest that combining leukotriene drugs with antihistamines may provide as much symptom relief as using inhaled steroids.