Find over 200 print-friendly fact sheets about heart disease and related health topics.
An allergic reaction is an overreaction of the immune system to
a substance called an allergen. Allergens include chemicals, foods, medicines,
mold, plants, and pollen.
Symptoms of an allergic reaction can
range from mild and annoying to severe and life-threatening.
Allergic reactions do not occur the first time a person is
exposed to an allergen. A person may become more sensitive to the allergen with
April 29, 2011
William H. Blahd, Jr., MD, FACEP - Emergency Medicine & H. Michael O'Connor, MD - Emergency Medicine
To learn more visit Healthwise.org
© 1995-2012 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.