- According to the National Health and Nutrition Examination Survey, more than 50 percent of the United States population deals with allergies on a regular basis. One of the factors that makes allergies so unpleasant, and in some cases dangerous, is histamine. The main choice for helping to combat this factor are antihistamines.
- When an allergen enters the body, the surrounding cells detect an invader and activates a lymphocyte cell to start the body's natural defense process. Usually this cell is a mast cell. As the mast cell is activated it releases a substance called histamine.
- When histamine is released into the body, it travels to the area that has been invaded by an allergen. Once there, it binds to the receptor sites (H-1 receptors) of other defense cells in the area. This sets off a chain of events that includes a rush of blood to the affected area, inflammation and the contraction of the surrounding smooth muscle.
- Antihistamines are medications that coat the histamine receptors in the body. With the receptors blocked by the antihistamines, histamine is unable to bind with its surrounding cells, in essence cutting off the allergic reaction before it can begin.
- Since antihistamines coat the receptors in the body, it is better to take a antihistamine before you have an allergic reaction. Once an allergic reaction has begun, it takes very little time for the histamine to activate the surrounding cells of an affected area. Taking an antihistamine a few hours before you know you may be exposed to an allergen, or taking a daily preventative antihistamine can ensure that the receptor sites are blocked before the histamine can be released.