allergy and immunology

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(Redirected from Allergology)

Allergy
Hives are a common allergic symptom.
Classification and external resources
ICD-10	T78.4
ICD-9	995.3
DiseasesDB	33481
MedlinePlus	000812
eMedicine	med/1101
MeSH	D006967

An allergy is a hypersensitivity disorder of the immune system.^[1]Symptoms include red eyes, itchiness, and runny nose, eczema, hives, or an asthma attack. Allergies can play a major role in conditions such asasthma. In some people, severe allergies to environmental or dietary allergens or to medication may result in life-threatening reactions calledanaphylaxis. Food allergies and reactions to the venom of stinging insectssuch as wasps and bees are more often associated with these severe reactions.^[2] Not all reactions or intolerances are forms of allergy.^[3]

Allergic reactions occur when a person's immune system reacts to normally harmless substances in the environment. A substance that causes a reaction is called an allergen. These reactions are acquired, predictable, and rapid. Allergy is one of four forms of hypersensitivity and is formally called type I (or immediate) hypersensitivity. Allergic reactions are distinctive because of excessive activation of certain white blood cellscalled mast cells and basophils by a type of antibody calledimmunoglobulin E (IgE). This reaction results in an inflammatory response which can range from uncomfortable to dangerous.

A variety of tests exist to diagnose allergic conditions. If done they should be ordered and interpreted in light of a person's history of exposure as many positive test results do not mean a clinically significant allergy.^[4] Tests include placing possible allergens on the skin and looking for a reaction such as swelling and blood tests to look for an allergen-specific IgE.

Treatments for allergies include avoiding known allergens, steroids that modify the immune system in general, and medications such as antihistamines and decongestants which reduce symptoms. Many of these medications are taken by mouth, although epinephrine, which is used to treat anaphylactic reactions, is injected. Immunotherapy uses injected allergens to desensitize the body's response. Mild allergies like hay fever are very common.

Immunology

From Wikipedia, the free encyclopedia

Immunology
A bacterium (MRSA, yellow) being ingested by an immune cell (Neutrophil, purple).
System	Immune
Subdivisions	Cellular Clinical Genetic (Immunogenetics) Humoral Molecular
Significantdiseases	Autoimmune disease Hypersensitivity Immune disorder Immunodeficiency
Significant tests	Agglutination Immunoassay Immunoprecipitation Serology
Specialist	Immunologist

Immunology is a branch of biomedical science that covers the study of all aspects of the immune system in all organisms.^[1] It deals with thephysiological functioning of the immune system in states of both health and diseases; malfunctions of the immune system in immunological disorders (autoimmune diseases, hypersensitivities, immune deficiency, transplant rejection); the physical, chemical and physiological characteristics of the components of the immune system in vitro, in situ and in vivo. Immunology has applications in several disciplines of science, and as such is further divided.

Even before the concept of immunity (from immunis, Latin for "exempt") was developed, numerous early physicians characterized organs that would later prove to be part of the immune system. The key primary lymphoid organs of the immune system are the thymus and bone marrow, and secondary lymphatic tissues such as spleen, tonsils, lymph vessels,lymph nodes, adenoids, and skin and liver. When health conditions warrant, immune system organs including the thymus, spleen, portions of bone marrow, lymph nodes and secondary lymphatic tissues can besurgically excised for examination while patients are still alive.

Many components of the immune system are actually cellular in nature and not associated with any specific organ but rather are embedded or circulating in various tissues located throughout the body.

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