Medical Encyclopedia allergen , that is contacted through the skin, lungs, swallowing, or injection. They occur more often in people with a family history of allergies . Most reactions happen soon after contact with an allergen . Most of these reactions are mild and can be treated at home. While first time exposure may only produce a mild reaction, repeated exposures may lead to more serious reactions.
Allergic reactions vary.
They can be mild or serious. They can be confined to a small area of the body or affect the entire body. Most occur within seconds or minutes after exposure to the allergen, but some can occur after days or weeks. DO NOT place a pillow under the victim's head if he or she is having trouble breathing . This can block the airway.