allergic reaction defined
Definition of reaction for English Language Learners. : 1  the way someone acts or feels in response to something that happens, is said, etc. : 2  an action or attitude that shows disagreement with or disapproval of someone or something. 3  reactions : the ability to act and move quickly in order to avoid sudden danger. Definition of reaction for English Language Learners. : the way someone acts or feels in response to something that happens, is said, etc. : an action or attitude that shows disagreement with or disapproval of someone or something. People with food allergies have an allergic reaction when they come in contact with certain foods. This happens because their immune system overreacts to the proteins in that food. Eight kinds of food cause most food allergies: • Cow's milk. Food Allergy. People with food allergies have an allergic reaction when they come in contact with certain foods. This happens because their immune system overreacts to the proteins in that food. Some people with food allergies can have a serious reaction called anaphylaxis. The first time a person with an allergy is exposed to the allergen, it may not cause a reaction. However, the person is then sensitized to the allergen can and even minor future exposures to this allergen produce an allergic reaction. Definition of reaction. 1  1a : the act or process or an instance of reactingb : resistance or opposition to a force, influence, or movement; especially : tendency toward a former and usually outmoded political or social order or policy. Its use in food allergies is unclear. Allergies are common. In the developed world, about 20% of people are affected by allergic rhinitis, about 6% of people have at least one food allergy, and about 20% have atopic dermatitis at some point in time. Depending on the country about 1–18% of people have asthma. Allergies, also known as allergic diseases, are a number of conditions caused by hypersensitivity of the immune system to something in the environment that usually causes little or no problem in most people. These diseases include hay fever, food allergies, atopic dermatitis, allergic asthma, and anaphylaxis. A reaction is an action taken in response to something. If you're telling your parents that you want to move out, you'll see by their reaction that they're sad about it. A reaction is often a physical in nature. A chemical reaction describes the way a chemical behaves when combined with another substance. The way your body responds to a medication or external influence is a physical reaction. Think of the way cold air causes you to get goose bumps on your arms. An allergic reaction occurs when the immune system overreacts to a harmless substance known as an allergen. The immune system protects the body from infections, viruses and diseases.
An allergic reaction occurs when the immune system overreacts to a harmless substance known as an allergen.