Allergies are abnormal reactions of the immune system to substances that are otherwise harmless. Allergies are among the most common medical disorders. By some estimates more than one in every five Americans suffer from some form of allergy. This...

Allergies A hypersensitive response by the immune system to a foreign substance that is ordinarily harmless. Allergies account for more office visits to pediatricians than any other ailment, besides the common cold, and are responsible for more missed...

Allergies are abnormal reactions of the immune system which occur in response to otherwise harmless substances. Allergies are among the most common of medical disorders. It is estimated that 60 million Americans, or more than one in every five people,...

An allergy is a reaction to a foreign substance by a person sensitive to that substance. Allergies are part of the body's immune mechanisms. They are triggered when an antigen--a substance foreign to the body--enters or contacts the body, which...

An allergy is an excessive or hypersensitive response of the immune system to harmless substances in the environment. Instead of fighting off a disease-causing foreign substance, the immune system launches a complex series of actions against an...

An allergy is an excessive or hypersensitive response of the immune system to harmless substances in the environment. Instead of fighting off a disease-causing foreign substance, the immune system launches a complex series of actions against an...

Elimination Diet A systematic approach for diagnosing food allergies. An elimination diet is the systematic elimination of different foods and food groups from the diet as a means of diagnosing food allergies. While people of all ages can develop an...

A delayed hypersensitivity test is an immune function test measuring the presence of activated T cells that recognize a certain substance. The immune system protects against infection by viruses, bacteria, fungi, and parasites. After initial exposure...

hypersensitivity reaction by the body to foreign substances (antigens) that in similar amounts and circumstances are harmless within the bodies of other people. Antigens that provoke an allergic reaction are called allergens. Typical allergens include...

Physical allergies are allergic reactions to cold, sunlight, heat, or minor injury. The immune system is designed to protect the body from harmful invaders such as germs. Occasionally, it goes awry and attacks harmless or mildly noxious agents, doing...

An allergy is an extreme reaction to an ANTIGEN present in the environment: antigens that produce an allergic reaction are called allergens. The most common allergies—hay fever for example, an allergic reaction to specific types of plant...

Exaggerated reaction by the body to foreign substances that are harmless to most people. Those substances, called allergens or antigens, may include pollens, drugs, dusts, foods, and other items. Immediate allergic reactions result from genetic...

A particular sensitivity on the part of an individual demonstrated on contact with a particular substance, the latter being known as an ALLERGEN. The allergic reaction is produced when allergens stimulate the production of ANTIBODIES that in turn...

Allergy is a disorder of the immune system that is often called atopy. Allergic reactions occur to environmental substances known as allergens; these reactions are acquired, predictable and rapid. Strictly, allergy is one of four forms of...