Allergy is described as an exaggerated reaction of the immune system to foreign bodies and substances that are not harmful to normal non-allergic individuals. The response by the immune system is exaggerated since it treats these foreign bodies as threats to the health of the body, instead of discarding and eliminating them like it normally would. This reaction is possible if a certain response of the immune system is activated.
The mechanism of allergies begins with the so-called exaggerated reaction of the immune system to antigens. Antigens are special substances that trigger the immune system to release its antibodies. Once an antigen invades the body, the immune system will try to work out the nature of antigen by identifying whether it is dangerous or not. In people who have not developed allergies, all antigens are not harmful.
However, for people who had antigens which underwent previous sensitization, selected antigens are treated by the body as threats. Among allergic people, the invasion of an antigen will trigger a series of immune response known as allergic cascade. The result of which are allergic reactions and symptoms characterizing the specific allergy or the specific body part affected by the antigen.
The antigen to which a person is allergic to is called allergen which comes in forms of animal dander, foods, drugs, chemicals, pollens, dust mites and others.
Allergens can penetrate the body through various entry points. These entry points are basically distinguished by the nature of the allergen. For example, nasal passages are the passageways for pollens, dust mites, dust, molds and other minute objects.
Allergens can also affect the body, but do not necessarily have to enter the inner body, through the contact with the skin or mucous membranes. Topical chemicals and substances are often the culprits of allergic responses on the skin. This allergic reaction differs with other allergic responses since it only triggers cells of inflammation which are located on the superficial layers of the skin and not the specific antibody that reacts to allergens- the IgE.
However, for some substances, contact does not end with the skin, they sometimes seep through the underlying structures to cause more severe allergic responses. There are also allergens that are injected to the body. These typically consist of materials that are injected mechanically or chemicals that insects carry. Lastly are the allergens that are ingested which compose of a variety of food that typically trigger allergic responses among humans, medications and drugs. In over sensitive individuals, even water components may pose as allergens.
The allergic cascade happens in three phases. It begins with the invasion of a common substance of the body’s system. If the immune system detects it as harmless, it will not respond aggressively, leading to the antigen’s elimination. However, if the immune system detects it as a threat, it will produce IgE or immunoglobulin E, an antibody that reacts to allergens, in massive quantities. IgE will then plot the allergen as harmful and will develop immune responses to it in succeeding encounters.
After sensitization comes another encounter with the antigen. By this time, the body has already developed exaggerated responses. Due to the release of some chemicals into the blood stream as it tries to eliminate the antigen, the body will experience the symptoms of the allergy.
These symptoms are the natural consequences of the immune response.