Use this glossary to learn common terms, medications, and phrases related to allergies.
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Allergens: Substances that can trigger asthma attacks in people who have allergic asthma. Examples of allergens are dog or cat dander, dust mites or pollen.
Allergen skin test: test in which tiny amounts of suspected allergens are introduced into a patient’s skin with a pin-prick. In an allergic patient, the allergen will produce a swollen itchy patch surrounded by an area of redness.
Allergic asthma: A type of asthma in which an allergen triggers cellular reactions resulting in airway inflammation and asthma symptoms.
Allergic conjunctivitis: Also called “pink eye,” this is an inflammation of the conjunctiva, the tissue on the inside of the eyelid and keeps eyeball and eyelid moist. It is an extremely common condition that can be triggered by contact with irritating substances such as shampoo, dirt, smoke, pool chlorine, or various allergens.
Allergic reaction: The immune system’s response to an invading allergen in which the mast cells produce the protective antibody called immunoglobulin E (IgE). The IgE antibodies trigger the mast cells to release histamine and other chemicals which produce inflammation, swelling, mucous production, itching, rash, hives or other symptoms, depending on the type of allergy.
Allergic rhinitis: An allergic reaction that mainly involves swelling and inflammation of nasal passages and sinuses, including the symptoms of congestion, sneezing, and itchy, watery eyes.
Allergy: The body’s over-response to a foreign substance, producing an allergic reaction and the release of histamine or other chemicals.
Animal allergens: Allergens from animal sources, such as particles of proteins secreted by glands in the animal’s skin, then shed as dander, proteins from an animal’s saliva, feces, urine or feathers.
Anaphylaxis: A runaway allergic reaction that involves the whole body. Anaphylaxis can be so severe as to be life-threatening. It can cause extreme swelling in the lungs and airways that can make breathing or swallowing difficult, as well as severe abdominal pain, cramps, vomiting, diarrhea and mental confusion or dizziness.
Antihistamine: A medication that blocks histamine receptors to prevents symptoms of inflammation, congestion, sneezing and itchy eyes.
Anti-inflammatory medications: Medications that reduce the inflammation and swelling of airways that can cause asthma symptoms.
Asthma attacks: The sudden or gradual worsening of asthma symptoms, such as coughing, wheezing and breathlessness.
Asthma symptoms: Common examples are coughing, wheezing, chest tightness and difficulty breathing.
Atopy: The genetic tendency to produce IgE and allergic reactions causing asthma, allergic rhinitis and skin allergies asthma in response to ordinary substances.
Bee sting allergy: An allergy to the venom from a bee sting. People who are extremely allergic to bees can have a severe reaction to a bee sting, including anaphylaxis.
Bronchoconstriction: Tightening of the airway muscles that makes it hard for the asthma sufferer to breathe.
Bronchodilators: Asthma medicines that relax airway muscles to open them up and allow more air through.
Contact dermatitis: See skin contact allergy.
Drug allergy: An allergy to certain medications such as penicillin, sulfa drugs, anti-seizure medications, and aspirin. An allergic person taking the drug may get hives or exhibit other symptoms.
Dust mites: A common allergen, dust mites are tiny insects that live in households, in mattresses, pillows, carpets, curtains and upholstered furniture.
Eczema: A very common form of dermatitis in people who are atopic. Its symptoms are dry, scaly skin appearing on red, inflamed areas. Eczema also is extremely itchy and may cause burning sensation. People who suffer from asthma or allergic rhinitis often have eczema as well.
Elimination diet: A diet used to test for food allergies. To determine the allergy, particular foods are temporarily eliminated from the diet to narrow down and identify the source of the allergy symptoms.
Epinephrine: A chemical also called adrenaline that is used in a self-injectable syringe to treat severe allergic reactions, such as anaphylactic shock from a bee sting.
Food allergy: An allergic reaction caused by a harmless food protein that can provoke symptoms such as inflammation, congestion and hives.
Food intolerance: A response that occurs when something in a food irritates a person’s digestive system or when a person is unable to digest the food. The most common food intolerance is intolerance to lactose, the sugar component of milk. It is different than a food allergy because it does not involve an allergic reaction.
Hay fever: A seasonal allergic reaction caused by the pollen of grasses, weeds, trees and other plants.
Histamine: A naturally occurring substance released by the mast cells after being exposed to a threatening foreign substance in the body or, in an allergic person, an allergen. The histamine causes inflammation, swelling, congestion, mucus production and other symptoms of allergies.
Hives: These are itchy, raised rashes or patches on the skin that can appear suddenly when someone eats or comes in contact with a food or drug they are allergic to. Hives, also called urticaria, can appear anywhere on the body including the tongue and throat and can disappear in a few minutes or last for days.
IgE (abbreviation for immunoglobulin E): An antibody your body creates that, in some people, can sensitize the mast cell to allergens and cause the chemical reactions that may lead to an allergic reaction or asthma attack.
IgE blockers: A new class of asthma medication that prevents the attachment of the IgE antibodies to the mast cells and prevents the allergic response that can lead to an asthma attack.
Inflammation of the airways: Swelling of the lung airway tissue, resulting in a narrowed airway and difficulty breathing.
Immunotherapy: Also known as allergy desensitization or allergy shots; immunotherapy can increase the tolerance to an allergen by reducing the body’s sensitivity to it. However, it is not considered a cure for allergies. Immunotherapy usually is reserved for people who for people who suffer from allergies three months a year or more.
Latex: Latex is a sap from the rubber tree that is used to make rubber gloves, tubing, rubber bands, and other products. The powder residue that coats the latex product, which can become airborne, is what causes an allergic reaction in some people.
Mast cell: A type of white blood cell that releases chemicals such as histamine that trigger an allergic reaction.
Mold: A microscopic fungi that produce spores that can become airborne like pollen; it is a common trigger for allergies. Indoor mold is found in damp areas, such as basements, bathrooms or rooms that have leaks or have been flooded. Mold can also be found outdoors in grass, leaf piles, mulch, or around mushrooms.
Pollen: A powdery substance released by plants and trees as part of their reproductive cycle. Pollen grains are a very common allergen that can cause allergic reactions in many people.
Peak expiratory flow meter: A tool that measures how well the lungs work. A person blows (exhales) quickly and forcefully into the meter, which gives a reading that tells how open the airways are.
Pink eye: See allergic conjunctivitis.
Radioallergosorbent test (RAST): A blood test to determine the presence of certain antibodies in the blood. High levels of these antibodies point to particular allergies. The RAST blood test is not considered as accurate as the allergen skin test.
Sinusitis: A bacterial infection in the sinuses that causes inflammation. Sinusitis can occur acutely with the flare up of a bacterial infection, or it can be chronic with nasal membranes constantly inflamed. The condition affects many people with asthma. However, experts say at least half of all chronic sinusitis is not caused by allergies.
Skin contact allergy: Also called contact dermatitis, this is a kind of allergic reaction of the skin caused by direct contact with an allergen producing symptoms of inflammation. The inflammation can range from localized redness to open sores, depending on the particular allergen, the part of the body affected, and the individual’s sensitivity.