WHAT IS ALLERGY
Allergy is an exaggerated response of our body when it comes into contact with certain substances from outside.
Substances capable of causing an allergic reaction are called allergens or simply allergens.
It is in the immune system or defense system of the human body, which is framed allergy. This system consists of a set of cells that are either circulating in the blood as part of various bodies. Its mission is critical to recognize the entry of foreign body and organize the defense against them. This is known as immune response. Thanks to her immune system recognizes the bacteria or viruses, agents outside our organization, as causing the infection. If not, any infection from which we suffer throughout our lives (a cold or flu) could have fatal consequences not find resistance to its progression.
As shown, the immune response is important but at times caused serious problems:
* In organ transplants (kidney, heart, lung …) our immune system identifies the new organ as foreign and try to put fighting, leading to rejection if no drugs are administered to reduce this response (called immunosuppressants).
* Sometimes the immune system components of our confused with foreign body and starts a reaction against them leading to the so-called autoimmune diseases (many rheumatic processes have this origin).
* Sometimes there is an immune response in the presence of harmless substances to the body, which are usually tolerated by it. This reaction is called an allergy exaggerated, and substances that are allergens trigger.
Potential allergens are very numerous and may contact us through various means:
* The air we breathe: plant pollens, house dust, molds, animal hair …
* Food: fish, eggs, nuts, …
* Drugs: penicillin, aspirin, …
* Insect Stings, bites, …
* Skin contact: cosmetics, industrial products, …
We are all exposed to many of these substances and yet most of us live with them without problems: we can eat peanuts and eggs, can be treated with penicillin, if needed … The immune reaction that our body produces these substances is compared with low intensity and not perceive.
On the contrary, a person allergic to a substance will trigger an exaggerated response each time it comes into contact with it. For this reaction takes place are sufficient trace quantities of allergen. Ultimately, the cause of an allergy should not be attributed to a specific substance, but the individual who is genetically predisposed to develop an exaggerated response after repeated contact with materials potentially capable of inducing a defensive reaction in the body.
More than 15% of the population is allergic to any substance. Fortunately, most allergic reactions are minor and cause no great inconvenience. However, it can sometimes be extremely serious and require urgent medical intervention.
Since the immune system is widely distributed in our body, it is not surprising that reactions to trigger allergic disorders are very different depending on where the reaction occurs:
* Digestive system: diarrhea, abdominal pain.
* Eyes: conjunctivitis (redness and itching).
* Nose: rhinitis (itchy and watery mucus secretion).
* Skin: Urticaria (hives and itching) and eczema.
* Lung: asthma (bronchial obstruction).
Type I allergic reaction
The man may present different kinds of immune reactions, but here we will consider only one of them (involving, for example, the onset of asthma). This is called type I allergic reaction
The cells that make up the immune system (macrophages and T cells and B) when in contact with a foreign body (allergen or antigen) initiated a series of reactions leading to the formation of molecules called immunoglobulins (Ig) or antibodies that bind to the allergen, and by various mechanisms, achieve their destruction and elimination.
These immunoglobulins can be 5 different types: IgG, IgA, IgM, IGD, and IgE.
IgE and, less frequently, IgG type 4 is involved in type I allergic reaction characteristic of asthma and the majority of allergic processes. People allergic to a substance (allergen) present on the surface of mast cells (cells of the blood) multiple IgE molecules capable of recognizing the presence of the substance. This IgE was formed in previous contacts with the allergen that caused awareness to it. Ie formed memory cells (memory B cells) which, upon contact with the allergen again, ordered the production of large quantities of specific IgE against that allergen. Upon the binding of IgE with the allergen (like a key lock and treatment) will lead to the release by the mast of a large number of substances (histamine, serotonin, bradykinin …), known as mediators allergy because they determine the manifestations of allergic reaction in different organs. Occur in the lung inflammation of the lining of the bronchial wall and contraction of the muscle fibers, resulting in asthma attack.
For all this to happen requires that the allergen enters the bronchial tree is a part of it directed against IgE (specific IgE). That is, each allergen IgE only in fits and is only found in sufficient numbers in people allergic to that allergen.
If a person is allergic to olive pollen will have your blood on the surface of mast cells molecules anti-IgE to olive pollen was not found in sufficient quantity in the rest of the population is allergic to it. It is known that mast cells could be crimped at its surface about 80,000 molecules of IgE. As mast cells are widely distributed throughout the body can imagine the large number of IgE molecules to reach an allergic individual is sensitized when.
Allergic MAJOR GROUPS
* The house dust mites (Dermatophagoides pt., Dt Lepidoglyphus, etc …)
* Pollens (grasses, olive, Parietaria, birch, etc …)
* Epithelium, hair, feathers and other animals (cat, dog)
* Fungi and their spores (mold).
* Dust grains and beans.
CONSTITUCION ATOP (or habit allergic)
People whose immune system to come into contact with environmental substances, it reacts by producing an excessive amount of IgE become allergic and atopic individuals are named. It is a genetically determined characteristic is inherited, usually affects several members of one family. This predisposition to allergy is usually manifested by various allergens, being much more rare allergy to only one substance.