From the Guidelines
Anaphylaxis is a severe, potentially life-threatening allergic reaction that requires immediate treatment with epinephrine (adrenaline) administered intramuscularly in a dose of 0.01 mg/kg of a 1:1000 solution to a maximum of 0.5 mg in adults and 0.3 mg in children, as recommended by the most recent guidelines 1.
Diagnosis of Anaphylaxis
The diagnosis of anaphylaxis is based on the clinical criteria proposed by the National Institute of Allergy and Infectious Diseases (NIAID), which include acute onset of symptoms, involvement of multiple organ systems, and a known or likely allergen exposure 1. The symptoms of anaphylaxis can vary, but common signs and symptoms include hives, swelling, difficulty breathing, wheezing, dizziness, and a drop in blood pressure.
Treatment of Anaphylaxis
The treatment of anaphylaxis involves the administration of epinephrine via an auto-injector, such as EpiPen or Auvi-Q, into the outer thigh muscle 1. After administering epinephrine, it is essential to call emergency services immediately and have the person lie flat with legs elevated unless they are having breathing difficulties. If symptoms persist after 5-15 minutes, a second dose of epinephrine can be given.
Prevention and Follow-up
Anyone with a history of anaphylaxis should carry epinephrine auto-injectors at all times, wear a medical alert bracelet, and have an emergency action plan 1. After an anaphylactic episode, follow-up with an allergist is essential to identify triggers and prevent future reactions. Common triggers of anaphylaxis include certain foods, medications, insect stings, and latex.
Key Points
- Anaphylaxis is a life-threatening allergic reaction that requires immediate treatment with epinephrine.
- The diagnosis of anaphylaxis is based on clinical criteria, including acute onset of symptoms and involvement of multiple organ systems.
- Epinephrine is the first-line treatment for anaphylaxis, administered intramuscularly in a dose of 0.01 mg/kg of a 1:1000 solution to a maximum of 0.5 mg in adults and 0.3 mg in children.
- After an anaphylactic episode, follow-up with an allergist is essential to identify triggers and prevent future reactions, as recommended by the most recent guidelines 1.
From the FDA Drug Label
1 INDICATIONS & USAGE Adrenalin® is available as a single-use 1 mL vial and a multiple-use 30 mL vial for intramuscular and subcutaneous use. Emergency treatment of allergic reactions (Type I), including anaphylaxis, which may result from allergic reactions to insect stings, biting insects, foods, drugs, sera, diagnostic testing substances and other allergens, as well as idiopathic anaphylaxis or exercise-induced anaphylaxis. The signs and symptoms associated with anaphylaxis include flushing, apprehension, syncope, tachycardia, thready or unobtainable pulse associated with hypotension, convulsions, vomiting, diarrhea and abdominal cramps, involuntary voiding, airway swelling, laryngospasm, bronchospasm, pruritus, urticaria or angioedema, swelling of the eyelids, lips, and tongue.
The diagnosis of anaphylaxis is based on the presence of signs and symptoms such as:
- Flushing
- Apprehension
- Syncope
- Tachycardia
- Hypotension
- Convulsions
- Vomiting
- Diarrhea and abdominal cramps
- Involuntary voiding
- Airway swelling
- Laryngospasm
- Bronchospasm
- Pruritus
- Urticaria or angioedema
- Swelling of the eyelids, lips, and tongue The treatment for anaphylaxis is emergency administration of epinephrine (IM) 2.
From the Research
Diagnosis of Anaphylaxis
- Anaphylaxis is a multisystem disorder that can manifest signs and symptoms related to the cutaneous, respiratory, cardiovascular, and gastrointestinal systems 3
- Symptoms of anaphylaxis include urticaria, difficulty breathing, and mucosal swelling, and can occur within one to two hours of exposure to an allergen 4
- Serum tryptase levels can be obtained to reflect mast cell degranulation when the clinical diagnosis of anaphylaxis is not clear 4
Treatment of Anaphylaxis
- Adrenaline (epinephrine) is the mainstay of acute pharmacotherapy for anaphylaxis and should be administered intramuscularly as soon as the diagnosis is suspected 5, 3, 6, 7
- The method of choice for administering adrenaline is by intramuscular injection with an autoinjector, given in the lateral portion of the thigh, and can be repeated every 10-15 minutes until there is a response 5
- The dose to be administered is 300-600 µg for an adult or 10 µg/kg for a child 5
- Antihistamines and corticosteroids are second-line medications and should never be given in lieu of, or prior to, epinephrine 3, 6, 4
- Aggressive fluid resuscitation should also be used to treat the intravascular volume depletion characteristic of anaphylaxis 3, 7
Management and Observation
- Patient observation and disposition should be individualized, as there is no well-defined period of observation after resolution of signs and symptoms 3, 7, 4
- Patients should be monitored for a biphasic reaction (i.e., recurrence of anaphylaxis without reexposure to the allergen) for four to 12 hours, depending on risk factors for severe anaphylaxis 4
- Following an anaphylactic reaction, management should focus on developing an emergency action plan, referral to an allergist, and patient education on avoidance of triggers and appropriate use of an epinephrine auto-injector 4