Incidence and Prevalence

About 40 million people in the United States suffer from some type of indoor or outdoor allergy. Many allergy sufferers have more than one allergy.

An allergy is an abnormal immune response to a substance that does not cause a reaction in most people. Any substance that causes an allergic reaction is referred to as an allergen. When a person who is allergic comes in contact with an allergen, his or her immune system responds to the allergen as if it were a harmful substance, causing an allergic reaction.

Several different substances can cause allergies. Hay fever is a type of outdoor allergy caused by plant pollen (e.g., ragweed) in the air. Certain foods and medications also can cause allergies. In some cases, people develop allergies to substances that are present inside their homes. These types of allergies are called indoor allergies.

• Dust mite debris
  Dust mites are microscopic creatures that thrive in warm, humid conditions. They exist in large numbers in bedding, such as pillows and mattresses. Dust mite waste products are a common allergen. These substances can build up over time within bedding materials and can be inhaled during sleep.
• Pet dander
  A protein in animal saliva is an allergen that triggers an immune response in people who have a pet allergy. This protein can be found on dead skin and hair debris from the pet and in the animal’s urine. This debris can become airborne in general house dust and then can be inhaled.
• Cockroach debris
  Cockroaches are difficult to fully exterminate in certain areas (e.g., in the southern United States, in large, older apartment buildings in urban areas). When cockroaches die, their bodies and waste products break down into small particles that can become airborne and can be inhaled.
• Mold
  Mold is a type of fungus that can grow on indoor as well as outdoor surfaces. Under the right conditions (e.g., damp, humid) within a home, mold can grow under flooring materials; behind walls; and on wood, sheet rock, or fabric. As it grows, mold produces spores that become airborne and can be inhaled.

• You sneeze again and again, especially after you wake up in the morning.

• You have a runny nose and postnasal drip. The drainage from a runny nose caused by allergies is usually clear and thin. But it may become thicker and cloudy or yellowish if you get a nasal or sinus infection.

• Your eyes are watery and itchy.

• Your ears, nose, and throat are itchy.

Which allergens commonly cause allergic rhinitis?

You probably know that pollens from trees, grasses, and weeds cause allergic rhinitis. Many people have allergies to dust mites, animal dander, cockroaches, and mold as well. Things in the workplace, such as cereal grain, wood dust, chemicals, or lab animals, can also cause allergic rhinitis.

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If you are allergic to pollens, you may have symptoms only at certain times of the year. If you are allergic to dust mites and indoor allergens, you may have symptoms all the time.

How is allergic rhinitis diagnosed?

To find out if you have allergies, your doctor will ask about your symptoms and examine you. Knowing what symptoms you have, when you get them, and what makes them worse or better can help your doctor know whether you have allergies or another problem.

If you have severe symptoms, you may need to have allergy tests to find out what you are allergic to.

Allergy Skin Testing

During an allergy skin test, your skin is exposed to allergy-causing substances (allergens) and then is observed for signs of a local allergic reaction. The areas of the skin react with redness or hives, showing the substances that person is allergic to. Along with your medical history, allergy tests can confirm whether signs and symptoms, such as sneezing, wheezing and skin rashes, are caused by allergies. Allergy tests can also identify the specific substances that trigger allergic reactions.

Allergy skin tests are safe, fast, accurate and relatively inexpensive. In most cases, they cause little pain or discomfort. Information from allergy tests can help your doctor develop an allergy treatment plan that may include allergen avoidance, medications or allergy shots (immunotherapy).

How is it treated?

There is no cure for allergic rhinitis. One of the best things you can do is to avoid the things that cause your allergies. You may need to clean your house often to get rid of dust, animal dander, or molds. Or you may need to stay indoors when pollen counts are high.

Unless you have another health problem, such as asthma, you may take over-the-counter medicines to treat your symptoms at home. If you do have another problem, talk to your doctor first. Others who also should talk to their doctor before starting self-treatment include older adults, children, and women who are pregnant or breast-feeding.

If your allergies bother you a lot and you cannot avoid the things you are allergic to, you and your doctor can decide if you should get allergy shots (immunotherapy) to help control your symptoms. For allergy shots to work, you need to know what you are allergic to.