Hay fever; Nasal allergies

An allergen is something that triggers an allergy. When a person with allergic rhinitis breathes in an allergen such as pollen or dust, the body releases chemicals, including histamine. This causes allergy symptoms.

Hay fever involves an allergic reaction to pollen. A similar reaction occurs with allergy to mold, animal dander, dust, and other allergens that you breathe in.

The pollens that cause hay fever vary from person to person and from area to area. Tiny, hard-to-see pollens often cause hay fever. Examples of plants that cause hay fever include:

• Trees
• Grasses
• Ragweed

The amount of pollen in the air can affect whether hay fever symptoms develop. Hot, dry, windy days are more likely to have increased amounts of pollen in the air. On cool, damp, rainy days most pollen is washed to the ground.

Some disorders may be linked to allergies. These include eczema and asthma.

Allergies are common. Your genes and environment may make you more likely to get allergies.

Allergies often run in families. If both your parents have allergies, you are likely to have allergies too. The chance is greater if your mother has allergies.

The health care provider will perform a physical exam and ask you questions about your symptoms. Your history of symptoms is important in diagnosing allergic rhinitis. You will be asked whether your symptoms vary by time of day or season, and exposure to pets or other allergens.

Allergy testing may reveal the substances that trigger your symptoms. Skin testing is the most common method of allergy testing. See the article on allergy testing for detailed information.

If your doctor determines you cannot have skin testing, special blood tests may help with the diagnosis. These tests can measure the levels of allergy-related substances, especially one called immunoglobulin E (IgE).

A complete blood count (CBC) test called the eosinophil white blood cell count may also help diagnose allergies.

LIFESTYLE AND AVOIDING ALLERGENS

The best treatment is to avoid what causes your allergic symptoms. It may be impossible to completely avoid all your triggers. However, you can often take steps to reduce your exposure to triggers such as:

• Dust
• Mold
• Pollen

There are many different medicines to treat allergic rhinitis. Which one your doctor prescribes depends on the type and severity of your symptoms, your age, and whether you have other medical conditions (such as asthma).

For mild allergic rhinitis, a nasal wash can help remove mucus from the nose. You can buy a saline solution at a drug store or make one at home using one cup of warm water, half a teaspoon of salt, and pinch of baking soda.

Treatments for allergic rhinitis include:

ANTIHISTAMINES

Antihistamines work well for treating allergy symptoms. They are often used when symptoms do not happen very often or do not last very long.

• Many antihistamines taken by mouth can be bought over the counter, without a prescription.
• Older antihistamines can cause sleepiness. They may affect a child's learning and make it unsafe to drive or operate machines.
• Newer antihistamines cause little or no sleepiness. They usually do not interfere with learning.
• Antihistamine nasal sprays work well for treating allergic rhinitis. You may try these medicines first.

CORTICOSTEROIDS

• Nasal corticosteroid sprays are the most effective treatment for allergic rhinitis.
• They work best when used nonstop, but they can also be helpful when used for shorter periods of time.
• Many brands are available. You will need a prescription from your doctor.
• Corticosteroid sprays are safe for children and adults.

DECONGESTANTS

• Decongestants may also be helpful for reducing symptoms such as nasal stuffiness.
• Do not use nasal spray decongestants for more than 3 days.

OTHER TREATMENTS

• The leukotriene inhibitor Singulair is a prescription medicine approved to help control asthma and relieve the symptoms of seasonal allergies.

Certain illnesses that are caused by allergies (such as asthma and eczema) may need other treatments.

ALLERGY SHOTS

Allergy shots (immunotherapy) are sometimes recommended if you cannot avoid the allergen and your symptoms are hard to control. This includes regular injections of the allergen. Each dose is slightly larger than the dose before it. Allergy shots may help your body adjust to the substance that is causing the reaction (antigen).

Most symptoms of allergic rhinitis can be treated. More severe cases need allergy shots.

Some people (especially children) may outgrow an allergy as the immune system becomes less sensitive to the allergen. However, once a substance causes allergies, it usually continues to affect the person over the long term.

Call for an appointment with your health care provider if:

• You have severe allergy or hay fever symptoms
• Treatment that once worked for you no longer works
• Your symptoms do not respond to treatment

You can sometimes prevent symptoms by avoiding known allergens. During pollen season, people with hay fever should stay indoors where it is air conditioned, if possible.

• Most trees produce pollen in the spring.
• Grasses usually produce pollen during the late spring and summer.
• Ragweed and other late-blooming plants produce pollen during late summer and early autumn.

Wallace DV, Dykewicz MS, Bernstein DI, Blessing-Moore J, Cox L, Khan DA, et al. The diagnosis and management of rhinitis: an updated practice parameter. J Allergy Clin Immunol. 2008 Aug:122(2).

Frew AJ. Allergen immunotherapy. J Allergy Clin Immunol. 2010 Feb;125(2 Suppl 2):S306-13.

Greiner AN, Hellings PW, Rotiroti G, Scadding GK. Allergic rhinitis. Lancet. 2011;378(9809):2112-2122.