Anaphylaxis (Severe Allergic Reaction)

  • Medical Author:
    Allison Ramsey, MD

    Dr. Allison Ramsey earned her undergraduate degree at Colgate University and her medical degree at the University of Rochester School of Medicine and Dentistry. She completed her internal medicine training at the University of Rochester School of Medicine and Dentistry and remained at the university to complete her fellowship training in allergy and clinical immunology. Dr. Ramsey is board certified in internal medicine and allergy and immunology. Her professional interests include the treatment of drug allergy and eosinophilic disorders. She also enjoys teaching medical trainees. She is a member of the American Academy of Allergy, Asthma, and Immunology, the American College of Allergy, Asthma, and Immunology, the New York State Allergy Society, and the Finger Lakes Allergy Society. In her personal life, her interests include exercise, especially running and horseback riding; and spending time with her husband and two children.

  • Medical Author: Syed Shahzad Mustafa, MD
    Syed Shahzad Mustafa, MD

    After growing up in the Rochester area, Dr. Mustafa pursued his undergraduate studies at the Johns Hopkins University in Baltimore and attended medical school at SUNY Buffalo. He then completed his internal medicine training at the University of Colorado and stayed in Denver to complete his fellowship training in allergy and clinical immunology at the University of Colorado, National Jewish Health, and Children's Hospital of Denver.

  • Medical Editor: Melissa Conrad Stöppler, MD
    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.

Quick GuideCould I Be Allergic? Discover Your Allergy Triggers

Could I Be Allergic? Discover Your Allergy Triggers

Recommendations after an initial episode of anaphylaxis

People who have experienced anaphylaxis of any cause should be educated about their trigger(s) and the signs and symptoms of anaphylaxis. Those at risk for anaphylaxis should carry self-injectable epinephrine (EpiPen, Adrenaclick) and understand when and how to use them. A wrist bracelet indicating the risk and trigger(s) for anaphylaxis can be helpful. Allergic diseases are often treated by avoidance measures, which will be reviewed in detail below.

What are emergency measures used in the treatment of anaphylaxis?

If you suspect that you or someone you are with is having an anaphylactic reaction, the following are important first aid measures. In general, try to perform these in the order that they are presented.

  • If the patient has injectable epinephrine, inject epinephrine immediately. The shot is given into the upper outer thigh and can be administered through clothing.
  • Call emergency services or 911 immediately.
  • Have a second injectable epinephrine device ready to use in case of a severe reaction or a biphasic reaction.
  • Place a conscious person lying down, and elevate the feet if possible.
  • Stay with the person until help arrives.
  • If trained, begin CPR if the person stops breathing or doesn't have a pulse.

After the initial epinephrine dose, if the symptoms are returning or still significant, one can inject another dose of epinephrine if available. All self-injectable epinephrine devices come in a two-pack for this reason. Even if anaphylaxis responds to epinephrine, a person should be monitored in an emergency-care setting. Steroids and antihistamines may be given, but these are not helpful in the initial management of anaphylaxis, and should not take the place of epinephrine. Steroids may be most helpful to prevent a biphasic reaction.

The normal side effects of epinephrine include pallor, shakiness, a rapid heart rate, and a sense of doom. These symptoms resolve rapidly, typically within minutes.

What is the treatment for anaphylaxis?

Epinephrine (also known as adrenaline) is the first-line therapy for anaphylaxis. It acts to reverse the effects of anaphylaxis on all body systems. Its effects include the following:

Skin: improves itching and hives

Respiratory: relaxes bronchial tubes in lungs, thus improving shortness of breath, chest tightness, and cough

Gastrointestinal: diminishes abdominal pain, cramping, and nausea

Cardiovascular: constricts blood vessels, thus improving blood pressure

Epinephrine also helps prevent the release of more mediators of the allergic reaction. Diphenhydramine (Benadryl) is not first-line therapy for anaphylaxis. This has primary effects on improving skin symptoms, such as hives and itching. In cases of severe anaphylaxis, in addition to epinephrine, other medications, IV fluids, and oxygen are administered once one receives care from a health-care professional. The choice of interventions will depend on the severity of the reaction.

Anaphylaxis may be biphasic roughly 20%-30% of the time. This is also known as a "late-phase reaction." In biphasic anaphylaxis, symptoms improve but then return hours to even days later. Treatment for biphasic reactions is the same as treatment of initial anaphylactic reactions. It is thought that steroids might reduce the risk of a biphasic reaction.

Medically Reviewed by a Doctor on 7/21/2016

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