Monday, August 24, 2009
What is Alergic Rhinitis?
When an allergen such as pollen or dust is inhaled by a person with a sensitized immune system, it triggers antibody production. These antibodies mostly bind to mast cells, which contain histamine. When the mast cells are stimulated by pollen and dust, histamine (and other chemicals) are released. This causes itching, swelling, and mucus production. Symptoms vary in severity from person to person. Very sensitive individuals can experience hives or other rashes. Particulate matter in polluted air and chemicals such as chlorine and detergents, which can normally be tolerated, can greatly aggravate the condition.
Sufferers might also find that cross-reactivity occurs.[4] For example, someone allergic to birch pollen may also find that they have an allergic reaction to the skin of apples or potatoes.[5] A clear sign of this is the occurrence of an itchy throat after eating an apple or sneezing when peeling potatoes or apples. This occurs because of similarities in the proteins of the pollen and the food.[6] There are many cross-reacting substances.
Some disorders may be associated with allergies: Comorbidities include eczema, asthma, depression and migraine.[7]
Allergies are common. Heredity and environmental exposures may contribute to a predisposition to allergies. It is roughly estimated that one in three people have an active allergy at any given time and at least three in four people develop an allergic reaction at least once in their lives. The two categories of allergic rhinitis include:
* Seasonal – occurs particularly during pollen seasons. Seasonal allergic rWhen an allergen such as pollen or dust is inhaled by a person with a sensitized immune system, it triggers antibody production. These antibodies mostly bind to mast cells, which contain histamine. When the mast cells are stimulated by pollen and dust, histamine (and other chemicals) are released. This causes itching, swelling, and mucus production. Symptoms vary in severity from person to person. Very sensitive individuals can experience hives or other rashes. Particulate matter in polluted air and chemicals such as chlorine and detergents, which can normally be tolerated, can greatly aggravate the condition.
Sufferers might also find that cross-reactivity occurs. For example, someone allergic to birch pollen may also find that they have an allergic reaction to the skin of apples or potatoes. A clear sign of this is the occurrence of an itchy throat after eating an apple or sneezing when peeling potatoes or apples. This occurs because of similarities in the proteins of the pollen and the food. There are many cross-reacting substances.
Some disorders may be associated with allergies: Comorbidities include eczema, asthma, depression and migraine.
Allergies are common. Heredity and environmental exposures may contribute to a predisposition to allergies. It is roughly estimated that one in three people have an active allergy at any given time and at least three in four people develop an allergic reaction at least once in their lives. The two categories of allergic rhinitis include:
* Seasonal – occurs particularly during pollen seasons. Seasonal allergic rhinitis does not usually develop until after 6 years of age.
* Perennial – occurs throughout the year. This type of allergic rhinitis is commonly seen in younger children.
Allergy testing may reveal the specific allergens a person is sensitive to. Skin testing is the most common method of allergy testing. This may include intradermal, scratch, patch, or other tests. Less commonly, the suspected allergen is dissolved and dropped onto the lower eyelid as a means of testing for allergies. (This test should only be done by a physician, never the patient, since it can be harmful if done improperly). In some individuals who cannot undergo skin testing (as determined by the doctor), the RAST blood test may be helpful in determining specific allergen sensitivity.