noun
definition
A substance which causes an allergic reaction.
example
Pollen, dust, and spores are common allergens.
Examples of allergen in a Sentence
It is claimed that these reduce the level of airborne cat allergen by about 50% .
Six hands still had detectable levels of peanut allergen.
At night, in bed, we spend on average eight hours in close contact with large amounts of house dust mite allergen.
Patients often assume that cat allergen is only present in the houses that are homes to cats.
Airway response to stimuli There are three phases to the asthmatic response of an atopic asthmatic following exposure to an allergen.
A brazil nut allergen was identified in soya bean genetically engineered with a brazil nut gene (Nordlee et al, 1996 ).
See the Guidance Notes on Food Labeling produced by the Food Standards Agency 11.4 What are the exceptions to allergen declarations on labels?
Antihistamine tablets and syrups Antihistamines prevent the histamine tablets and syrups Antihistamines prevent the histamine your body produces to the allergen from causing the allergic symptoms.
In response to an allergen entering the body, mast cells in our immune systems release histamine, the substance that causes allergic symptoms.
Chicken egg lysozyme is a well- known potent food allergen [18] while human lysozyme is clearly not allergenic.
The symptoms include a red, itchy rash where the allergen has been in contact with the skin.
The body's immune system becomes sensitive to the allergen.
In addition, the animal becomes tolerant to the allergen.
Any substance that triggers an allergic reaction is called an allergen.
It is known that different breeds of cats have different levels of the glycoprotein Fel D 1, the allergen that causes cat allergies in people.
Clients that experienced an allergic reaction are said to be extremely allergic to cats and are believed to have had a reaction to an allergen other then FEL D1.
Low allergen and hypoallergenic cats may be the answer for many allergy sufferers who dream of sharing their life with a feline friend, but it's clear prospective owners will have to pay a hefty price for that pleasure.
If something causes an allergic reaction, you'll know it's an allergen and you can eliminate it from her diet.
Allergic reactions may be dose dependent; that is, longer exposure or exposure to larger amounts of the offending allergen may cause a greater response of the immune system and result in a stronger reaction.
Provocation testing involves direct exposure to a likely allergen, either through inhalation or ingestion.
In percutaneous or prick testing, a drop of each allergen to be tested is placed on the skin, usually on the forearm or the back.
A typical battery of tests may involve two dozen allergen drops, including a drop of saline solution that should never provoke a reaction (negative control) and a drop of histamine that should always provoke a reaction (positive control).
Intradermal testing involves directly injecting allergen solutions into the skin.
Separate injections are made for each allergen tested.
If antibodies against a particular allergen are present, those antibodies will bind to the solid medium and remain attached after being rinsed.
A purified preparation of the allergen is inhaled or ingested in increasing concentrations to determine if it will provoke symptoms.
In bronchial provocation challenges, the individual inhales increasingly concentrated solutions of a particular allergen prepared in a nebulizer.
Intradermal testing may inadvertently result in the injection of the allergen into the circulation, with an increased risk of adverse reactions.
This reaction does not mean the substance actually causes the child's symptoms, however, since he or she may have no regular exposure to the allergen.
In fact, the actual allergen may not have been included in the test array.
Following allergen inhalation, reduction in exhalation capacity of more than 20 percent, and for at least 10 to 20 minutes, indicates a positive reaction to the allergen and the sensitivity of the individual being tested.
Gastrointestinal symptoms within 24 hours following the ingestion of a suspected food allergen indicates a positive response and sensitivity to that food allergen.
Histamine-A substance released by immune system cells in response to the presence of an allergen.
Contact dermatitis is a rash that appears after the skin is exposed to an allergen, such as metal, rubber, some cosmetics or lotions, or some types of plants (e.g. poison ivy).
The rash triggered by allergies should disappear as soon as the allergen is removed; drug rashes will fade when the person stops taking the drug causing the allergy.
In a food allergy or sensitivity, when the child eats a particular food, (such as eggs, for example) usually by the time the eggs reach the stomach or the intestines, the body reads the presence of eggs as an allergen (something harmful).
Parents need to become proficient label readers, especially if the allergen is a nut or other food that may cause anaphylaxis.
Allergy shots, also called immunotherapy, are a form of treatment that reduces a person's allergic reaction to a particular allergen.
The incremental increases of the allergen cause the child's immune system to become less sensitive to the substance by producing a "blocking" antibody.
Depending on the severity and nature of the allergies, allergen avoidance and allergy medications alone may not effectively manage symptoms in children.
A pediatric allergist can diagnose the specific cause of the allergic reaction and provide the correct allergen extracts.
The child's particular allergen may be difficult or impossible to avoid because of exposure to environment.
The allergist may decide to conduct skin testing on a child to determine the specific allergen that is causing a reaction in the child.
This condition is unusual, since the amount of allergen used is small; however, it can happen if the child is highly sensitive to the allergen.
Once the testing is finished, the allergist prepares an allergen abstract (serum) specially for the child.
In this treatment, steadily increasing doses of allergen extract are given every few hours instead of every few days or weeks.
Children who are allergic to certain substances, medications, or foods can avoid the resulting itch if they avoid contact with the allergen.
Antihistamines work by blocking the effects of histamine, a chemical released by mast cells during an allergic response to an allergen.
Conjunctivitis caused by an allergic reaction should clear up once the allergen is removed.
However, allergic conjunctivitis will likely recur if the individual again comes into contact with the particular allergen.