A normal reaction to a sting is localized, with swelling, redness and pain occurring near the sting site. Some people swell more than others. A sting on the wrist may cause the arm to swell up to the elbow. Some people show a delayed reaction, with symptoms appearing one to several hours later.
An abnormal or systemic reaction involves generalized symptoms that occur away from the sting site, such as hives, profuse sweating, shortness of breath and tightness of the throat. A victim with these symptoms should be taken immediately to a hospital for treatment. Treatment usually includes a shot of epinephrine. Persons who are aware they are allergic should carry an epinephrine kit, “EPI KIT,” prescribed by their doctor. Epinephrine stabilizes the vascular system, preventing throat swelling that could inhibit breathing. Epinephrine should not be given to a victim who has a heart condition. Abnormal reactions usually occur soon after the person has been stung, but less often, the reaction may be delayed.
– John Skinner, University of Tennessee