Net Sightings allergy_headache

Allergy, allergies, antigens and allergens, what are they? Allergies can be identified as hypersensitive reactions by the body to foreign substances (otherwise known as antigens) that in similar amounts and circumstances can be harmless within the bodies of other people.

Antigens that lead to an allergic reaction are known as allergens. Common allergens can include pollens, drugs, lints, bacteria, foods, dyes and chemicals. The immune system embodies several mechanisms that normally guard the body against antigens and prevent allergies from occuring.

Type 1 allergy, which include insect venom allergy, hay fever, and asthma, involve the strand of antibodies known as immunoglobulin E (IgE). Symptoms of an allergic reaction can include: runny nose, wheezing, and tissue swelling. Antihistamine medication is often used to give temporary relief.

Type 2 allergy can occur when antibodies react with antigens that are found on certain cells in the body causing allergic reactions. The antigen-antibody complex activates a series of potent enzymes that attack certain cells in our immune system.

Type 3 allergies occur when a person who is highly sensative to a certain antigen is subsequently exposed to that antigen. The antigen-antibody complex stores itself on the walls of the small blood vessels, which then triggers inflammation and vascular damage. The best protection of these types of allergies is avoidance of known allergens.

Type 4 allergic reactions appear 12 - 24 hours or more after exposure to an appropriate antigen. Such allergies include: dermatitis and rejection of transplanted organs.