1. 10 Common Allergy Triggers Slideshow Pictures
2. Take the Quiz on Allergies
3. Nasal Allergy Relief Slideshow: Products That Work

Medical Author:

Jerry R. Balentine, DO, FACEP

Jerry R. Balentine, DO, FACEP

Dr. Balentine received his undergraduate degree from McDaniel College in Westminster, Maryland. He attended medical school at the Philadelphia College of Osteopathic Medicine graduating in1983. He completed his internship at St. Joseph's Hospital in Philadelphia and his Emergency Medicine residency at Lincoln Medical and Mental Health Center in the Bronx, where he served as chief resident.

View Full Profile

Medical Editor:

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

View Full Profile

In this Article

• Anaphylaxis facts
• Introduction to anaphylaxis
• What is the history of anaphylaxis?
• How common is anaphylaxis?
• What are common causes of anaphylaxis?
• What are the signs and symptoms of anaphylaxis?
• What happens after the symptoms begin?
• Are there any disorders that appear similar to anaphylaxis?
• How is anaphylaxis diagnosed?
• How do we manage anaphylaxis?
• What are emergency measures used in the treatment of anaphylaxis?
• Can anaphylaxis be prevented?
• Patient Comments: Anaphylaxis - Possible Causes
• Patient Comments: Anaphylaxis - Diagnosis
• Patient Comments: Anaphylaxis - Symptoms and Signs
• Patient Comments: Anaphylaxis - Describe Your Experience
• Find a local Doctor in your town
• Anaphylaxis Index

There are three possible outcomes:

1. The signs and symptoms may be mild and fade spontaneously or be quickly ended by administering emergency medication. In this outcome, the symptoms do not subsequently recur from this particular exposure.


2. After initial improvement, the symptoms may recur within four to 12 hours (late phase reaction) and require additional treatment and close observation. Recent evidence suggests that a late-phase reaction occurs in fewer than 10% of cases.


3. Lastly, the reaction may be persistent and more severe, thus requiring intensive medical treatment and hospitalization. This may occur up to 20% of the time with certain exposures.

Epinephrine, which is also known as "adrenaline," is a drug that acts immediately to cause the blood vessels to contract, thereby preventing fluid leakage. It is one of the medications frequently used to treat anaphylaxis. Epinephrine also helps relax the bronchial tubes, thus relieving breathing difficulty. It also lessens stomach cramps and stops itching and hives. More importantly, epinephrine helps prevent the release of more mediators of the allergic reaction.

In addition to epinephrine, other medications and IV fluids and oxygen will probably be administered as well. The choice of interventions will depend on the severity of the reaction the patient experiences. Epinephrine given to someone who does not have anaphylaxis can lead to a dangerously fast heart beat and severe hypertension. It should only be administered by medical personnel familiar with its use and indications or patients who were prescribed an EpiPen by their health-care provider.

Several disorders may appear similar to anaphylaxis. Fainting (vasovagal reaction) is the reaction that is most likely to be confused with anaphylaxis. The key differences are that in a fainting episode, the affected person has a slow pulse, cool and pale skin, and no hives or difficulty breathing. Other conditions, such as heart attacks, blood clots to the lungs, septic shock, and panic attacks can also be confused with anaphylaxis.