Anaphylactic shock

Anaphylactic shock Definition:
Anaphylactic shock, is the most severe type of anaphylaxis. Anaphylactic shock can occur in response to any allergen, when an allergic response triggers a quick release from mast cells of large quantities of immunological mediators (histamines, prostaglandins, leukotrienes) leading to systemic vasodilation and edema of bronchial mucosa (resulting in bronchoconstriction and difficulty breathing). The reaction of anaphylactic shock may include itchy skin, edema, collapsed blood vessels, fainting, difficulty in breathing, and death.

What is causes of Anaphylactic shock?
Your immune system produces antibodies that defend against foreign substances. This is good when a foreign substance is harmful (such as a bacterium or virus). But some people's immune systems overreact to substances that shouldn't cause an allergic reaction.

1. The body's white blood cells produce substances called antibodies as a reaction to that antigen. The antibodies circulate in the bloodstream and attach themselves to certain cells in the body.

In an allergic reaction, the antibody is called immunoglobulin E.
When the antibodies come in contact with the antigen, they signal other cells to produce certain chemicals called "mediators." Histamine is an example of a mediator.
The effects of these mediators on organs and tissues of the body cause the symptoms of the reaction.

2. Triggers of anaphylaxis include many substances. Only a trace amount of the trigger may be needed to cause a severe reaction. Triggers of allergic reactions, including anaphylaxis, may include:

Prescription and over-the-counter medications (see Drug allergy). This is usually due to a toxic reaction, rather than the immune system response that occurs with "true" anaphylaxis.
Venom of stinging insects such as yellow jackets, bumble bees, honey bees, wasps, fire ants.
Foods, especially high-protein foods - most commonly, shellfish, fish, nuts, fruit, wheat, milk, eggs, soy products.
Food additives, such as sulfites.
Transfusion of blood or blood products.
Numerous other substances such as latex (natural rubber).
Dyes and contrast materials used during radiologic procedures or tests.

3. Sometimes the trigger of the reaction is obvious--a bee sting, or a new prescription drug.

4. People with asthma, eczema, or hay fever are slightly more likely to have an anaphylactic reaction than people who do not have these conditions.