One may wonder why does the immune system make this mistake? It appears that the allergic response was once meant to protect the body against parasitic infections. No one really knows why the immune system would recognized non-harmfull substance as foreign in the same way. It appears that a number of factors predispose certain individuals to become allergic. The most important being genetics. A person's genetic makeup can put them at risk of becomming an allergic individual. This is why family history is one of the most important risk factors for allergies. Allergies can occur at any time during our lives, but are more common to occur during childhood or young adulthood.
When a person is exposed to an allergen, a series of events takes place:
- The body starts to produce a specific type of antibody, called IgE, to bind the allergen.
- The antibodies attach to a form of blood cell called a mast cell.
- The allergens bind to the IgE, which is attached to the mast cell. This triggers a reaction that allows the mast cells to release a variety of chemicals including histamine. If the allergen is in the air, the allergic reaction will likely occur in the eyes, nose and lungs. This leads to runny nose,congestion,itchy watery eyes, sneezing and drainage in the back of your throat. If a patient has allergic asthma then this could also induce an asthma attack. If the allergen is ingested(for example a certain food or medication) the allergic reaction often occurs in the mouth, stomach, and intestines. Sometimes enough chemicals are released from the mast cells to cause a reaction throughout the body, such as hives, decreased blood pressure, shock, loss of consciousness or even death.
The allergic person can make allergic antibodies, to a variety of different foreign substances such as certain foods, drugs and airborn allergens. There are a number of different aeroallergens including outdoor(trees, grasses,weeds and molds) and the indoor allergens such as dust mites, animal dander(cat and dog),feathers and cockroach.