Allergy
Online 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
hypersensitivity and is called type I (or immediate) hypersensitivity. It is
characterized by the agency of excessive activation of certain pure blood cells
called mast cells and basophils by a pattern of antibody, known as IgE, resulting
in an last fiery response.
Common allergic reactions include eczema, hives, hay flush,
asthma, food allergies, and reactions to the venom of stinging insects such like
wasps and bees. Mild allergies like hay fever, are highly prevalent in the human
population and account symptoms such to the degree that allergic conjunctivitis,
itchiness and runny nose. Similarly, conditions such as asthma are frequent,
in which allergy plays a major role. In some people, severe allergies to environmental
or dietary allergens, or to medication, occur that may result in life-threatening
anaphylactic reactions and potentially death.
A variety of tests now exist to diagnose allergic stipulations;
these include testing the skin for responses to known allergens or analyzing
the blood for the presence and levels of allergen-specific IgE. Treatments
for allergies embody allergen avoidance, use of antihistamines, steroids or other
oral medications, immunotherapy to desensitize the response to allergen, and
targeted therapy. Classification and history The concept 'allergy' was originally
introduced in 1906 by the Viennese pediatrician Clemens von Pirquet, after noting
that some of his patients were hypersensitive to normally innocent entities such
being of the class who dust, pollen, or certain foods.
Pirquet called this phenomenon 'allergy' from the Greek
words allos meaning 'other' and ergon meaning 'work'. Historically, all forms
of hypersensitivity were classified as allergies, and whole were thought to be
caused by the agency of every improper activation of the immune system. Later,
it became clear that several different disease mechanisms were implicated, with
the public link to a disordered activation of the immune system. In 1963, a new
classification draught was designed by Philip Gell and Robin Coombs that described
four types of hypersensitivity reactions, known as Type I to Type IV hypersensitivity.
through this new classification, the word 'allergy' was restricted to only type
I hypersensitivities (also called immediate hypersensitivity), which are characterized
as rapidly developing reactions.