Physiology of anaphylaxis


Anaphylaxis is a severe allergic reaction by the body’s immune system to exposure to foreign substances (antigens).

The immune system produces antibodies to defend against antigens. These antibodies are also known as immunoglobulins (Ig), which are a type of protein called globulins.

Allergic reactions

Immunoglobulin E (IgE) is the specific antibody involved in allergic reactions.

There are thousands of different types of these IgE antibodies existing in a dormant state.

When someone is first exposed to an antigen (allergen), it stimulates IgE antibodies specific to that antigen. The individual may not experience obvious symptoms during this initial exposure.

The immune response is stronger after a second or subsequent exposure to the allergen because the body has already sensitised IgE antibodies to react to the antigen. This heightened response can lead to allergic symptoms or, in the case of anaphylaxis, a severe allergic reaction.

Click on hotspots below to see symptoms.

In conjunction with the lgE antibodies, mast cells and basophils can become attached to the antigen.

These cells contain substances such as histamine and kinins (cell mediators), which are released from the cell.