One of the marvels of the human body is that it can defend itself against harmful invaders such as viruses or bacteria. In the process, some unpleasant and, in extreme cases, life-threatening symptoms may be experienced. Hundreds or even thousands of ordinary substances can trigger allergic reactions.
Allergies can affect anyone, regardless of age, gender, race or socioeconomic factors.
While it's true that allergies are more common in children, they can occur for the first time at any age or, in some cases, recur after many years of remission. Although the exact genetic factors are not yet understood, the tendency to allergies, as well as to allergic disease, is linked to heredity. Yet in allergy shots, repeated exposure to an allergen is used to build up immunity. Regularly scheduled, repeated exposure to small amounts of an allergen can lead to immunity, whereas infrequent and erratic exposure does not confer immunity but increases the likelihood of producing allergen sensitization. The presence of these antibodies, when exposed to an allergen can lead to an allergic reaction.