|
Allergies are a very common occurrence among a large portion of the general population. An allergy can be described as an inappropriate response by the body's immune system to a substance that is not normally harmful. This substance, or allergen, is seen as a foreign invader to the immune system, triggering an allergic reaction. Typical allergic responses include nasal congestion, coughing, wheezing, itching, headaches and skin rashes.
An allergic reaction often includes the release of a protein called histamine from mast cells in the body. Histamine causes different things to happen in the body including several allergic symptoms. It causes dilation of arteries (giving a reddish look), swelling (such as hives), itching, decreased blood pressure, constriction of the smooth muscle and several other effects. It can also affect the amount of stomach acid released, and strongly stimulates sensory nerve endings. Histamine plays a role in the inflammatory response process. Along with other substances, histamine can cause further effects, such as asthma. However, this study did not look at the effects of niacin on asthma.
Histamine causes the blood vessels to become more permeable, allowing fluid to leak into tissues. This is what causes the swelling in an allergic reaction. The most commonly used treatment for allergic reactions is antihistamines. Antihistamines are a class of "antiallergic drugs" and are available as over-the-counter or prescription medications.
When exposed to an allergen, histamine binds to cells in the body, which causes the above reactions. Antihistamine works by beating the histamine to the cell and binding to more cells than the histamine.
|
|
