- Prevent its production.
- Accelerate its destruction.
- Prevent it from attaching to the receptors.

On the other hand, it is necessary to take into account that these drugs have been classified as classical or non-sedating first generation or second generation, and then describes their main characteristics.

First generation. They are used most often in cases of rhinitis, dermatitis, urticaria and conjunctivitis, and are characterized by transient cause drowsiness, loss of ability to drive or operate machinery and, occasionally, stimulation of appetite.

These include azelastine, brompheniramine, cyproheptadine, chlorpheniramine, diphenhydramine, dimenhydrinate, dimetindeno, doxylamine, fenoxifenadina, isotipendilo, promethazine, triprolidine and dexbromfeniramina, are incorporated into the formulas of influenza because they are effective in controlling runoff and nasal congestion, sneezing and tearing.

Second generation. Show a greater safety profile than previous because the patient is kept without sleep and alertness also are recommended mainly in cases of angioedema, conjunctivitis, asthma and urticaria. This group terfenadine, astemizole, epinastine, cetirizine, and loratadine ebastatina, the latter already incorporates some flu.

With antihistamines that has put the pharmaceutical industry reach allergies and need not be a nightmare, does not mean to be consumed indiscriminately. Remember that the most important thing is prevention, so avoid, as far as possible, all substances to which it has detected that is sensitive.

To diagnose allergies the patient may be subjected to one or more of the following clinical studies:

Measurement of immunoglobulin E. Blood test that reveals the total amount of the antibody in the body when in contact with an allergen.

Skin tests. Consist of applying in the forearm or back different substances that can cause allergy, such as dust, mold, pollen, animal hair, cosmetics, metals, food and medicine. Those affected by this disease have redness, hives and itching 15 minutes later.

Patch testing. When practicing different substances are placed on the skin of the back, which are covered with patches for 48 or 72 hours later, we review in which regions of the epidermis was allergic response.

Antihistamines when administering

Antihistamines are of great help in controlling allergic type diseases, such as:

Angioedema. Inflammation and fluid accumulation in the deeper layers of the skin, especially as part of hands, feet and face, although it may occur in the throat and difficulty breathing or swallowing ability. Its appearance is associated with the ingestion of certain foods and medications that are not well tolerated by the body.

Asthma. Chronic disease that clogs the respiratory tract because it inflames the tubes that carry air to the lungs, usually manifests itself by presenting an exaggerated sensitivity to irritants such as pollen, smoke, dust, certain products or animal hair.

Conjunctivitis. Swelling and redness of the conjunctiva (the membrane located between the eye and inner eyelid, which is responsible for maintaining the required humidity), characterized by causing discharge, burning, irritation and tearing.

Dermatitis. Skin inflammation that occurs when the tissue comes into contact with irritating substances contained in plants, cosmetics, detergents, synthetic fibers, metal jewelry, insect bites, and by the action of any medicine or food. Cause characterized by redness, blisters, dryness, flaking and itching difficult to control.

Allergic rhinitis. Inflammation of the lining of the nose that causes dripping, itching, sneezing, runny nose, stuffy ears, diminished sense of smell, headache and fatigue, occurs when inhaled environmental pollutants, pollen, or is in contact with animals.

Urticaria. Eruption of hives all over the skin accompanied by intense itching and swelling occurs when skin is exposed to irritants, metals and some plants, or by eating food or medicine to which sensitivity has been developed.

The environment we are exposed contains both harmless and harmful elements, which can enter the body through the respiratory tract, gastrointestinal tract, skin and mucous membranes, and when this happens, the immune system (the one who defends us from external aggression) is activated and identifies whether the substances that enter the body are harmful or not.

However, there are times when acts unreasonably and recognized as dangerous (when in reality they tend to affect most people), leading to the production of histamine, compound responsible for producing allergic reactions can be manifested by congestion and runny nose, watery eyes, sneezing, sore skin, rashes, itching, dizziness, headache and diarrhea.

To control these annoying symptoms usually uses antihistamines, drugs that block the action of histamine and relieve discomfort. Before delving into the characteristics of these drugs should learn more about allergies and the mechanisms that trigger.

Allergies and Risk Factors

Those who suffer this type of condition have alterations in the immune system, which leads to attack items and substances that normally do not react the majority of individuals. One of the most important components of that system in its fight against allergens (allergy-causing elements) are the immunoglobulins (antibodies) of the type E which is critical in allergic responses, as when an individual is produced in larger quantities has more risk for the disease in question.

When manifest allergy, immunoglobulin E release various chemicals, among which histamine, responsible for causing vasodilation (inflammatory reaction), skin redness, hives, an accumulation of fluid in mucous, congestion, runny nose, sneezing, watery and / or diarrhea.

However, it is important to know that the body there are three types of receptors (structures that receive a substance to produce a reaction) for histamine, which include:

H1. They relate to the immediate allergic response and the appearance of the following symptoms: runny nose, sneezing, itchy nose and throat and to a lesser degree, watery eyes, redness and swelling in eyes and a rash of rashes. Found in the hypothalamus (gland in the brain responsible for regulating hormone), neurons (nerve cells), blood vessels and certain regions of the brain.

H2. Involved in regulating the secretion of gastric juice and hydrochloric acid stomach.

H3. Are present in nerve endings and are responsible to self-regulate the release of histamine.

There exist several risk factors that may lead to the development of allergies, which include the following conditions:

- Family history, for when one or both parents have allergies will inherit a predisposition to their children.
- Exposure to environmental pollutants.
- Stay for long periods in places with poor ventilation.
- Living in a house with rugs and carpets that are not provided with proper maintenance (cleaning and disinfection).
- Living with animals.
- Suck tobacco smoke, dust or pollen.

Doctors call the cold allergy, cold urticaria and its most common symptoms are:

* Itching, skin redness and hives.
* Swelling of the hands when holding cold objects.
* Swelling of the lips to eat cold food.
* In rare cases, severe swelling of the tongue and throat that can block breathing (swelling of the throat).

Most often, these symptoms do not occur when the person is exposed to cold but somewhat later when the body is taking heat.

There can also be very severe allergic reactions, especially when diving in cold water, which may cause syncope and death by drowning. The severity of symptoms varies in each case and the most common is itching.

In addition, various types of allergy to cold, but no cure, although in some cases the allergy goes away by itself. People suffering from cold allergy should avoid it and continue medical treatment

An allergy is an exaggerated response of our organism, when in contact with certain substances from outside. Substances capable of causing an allergic reaction are called allergens or simply allergens.

How do you get?

The immune response is of great importance but sometimes causes serious problems:

In organ transplants (kidney, heart, lung …) our immune system identifies the new organ as foreign and try to put in place to combat it, if not the rejection medications are given to reduce this response (called immunosuppressants).

Sometimes confuses the immune system components of our body with foreign elements and starts a reaction against them leading to the autoimmune diseases (many rheumatic conditions are the origin).

Sometimes it produces an immune response in the presence of harmless substances to the body, which are usually tolerated by it. This overreaction is called allergy and the substances are allergens that trigger. The potential allergens are very numerous and may contact us through various means:

The air we breathe: plant pollens, house dust, fungi, animal hair … Food: fish, eggs, nuts, … Drugs: penicillin, aspirin, … Insect stings, bites, … Skin contact: cosmetics, industrial products …

Symtomps

• Gastrointestinal: diarrhea, abdominal pain.
• Eyes: conjunctivitis (redness and itching).
• Nose: rhinitis (itchy and watery mucus secretion).
• Skin: urticaria (hives and itching) or eczema.
• Lung: asthma (bronchial obstruction).

Treatment And Recommendations

The cells that compose the immune system (macrophages and T cells and B) when in contact with a foreign substance to the (allergen or antigen) initiated a series of reactions that culminate in the formation of molecules called immunoglobulins (Ig) or antibodies that bind to the allergen and, through various mechanisms, get their destruction and disposal.

These immunoglobulins can be 5 different types: IgG, IgA, IgM, IgD, and IgE. IgE and, less frequently, IgG type 4 are those involved in type I allergic reaction characteristic of asthma and most allergies. People allergic to a substance (allergen) present on the surface of mast cells (blood cells) multiple IgE molecules capable of recognizing the presence of the substance.

This IgE was formed in previous contacts with the allergen that caused the sensitization to the same. That is, they formed the memory cells (memory B cells) which, upon contact with that allergen again, order the production of large amounts of specific IgE against that allergen. At the time the binding of IgE with the allergen (like a key and lock it were) will cause the release by the mast of a large number of substances (histamine, serotonin, bradykinin mediators known as …), Allergy They alone 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 an asthma attack.

Credit to: Dr. Gustavo Castillo