What is the management of severe allergic reactions (anaphylaxis)?

From the Guidelines

Severe allergic reactions require immediate treatment with epinephrine (adrenaline) as the first-line medication, with 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, administered intramuscularly into the anterolateral thigh. This is based on the most recent and highest quality study, which emphasizes the importance of prompt epinephrine administration in anaphylaxis management 1. The study highlights that epinephrine is the cornerstone of anaphylaxis treatment, but it continues to be underutilized.

Key Considerations

• The dose of epinephrine can be repeated every 5-15 minutes if symptoms persist, as stated in previous guidelines 1.
• After administering epinephrine, it is crucial to call emergency services immediately.
• Secondary treatments, such as antihistamines (e.g., diphenhydramine) and corticosteroids (e.g., prednisone), may be used to help prevent prolonged reactions, but their role is less clear and they should not be considered substitutes for epinephrine 1.
• Patients with known severe allergies should carry epinephrine auto-injectors at all times, wear medical alert identification, and have a written emergency action plan.

Long-term Management

• Prevention through allergen avoidance and immunotherapy may be recommended for long-term management, as suggested in guidelines for food allergy management 1.
• Education on allergen avoidance, early recognition of anaphylaxis signs and symptoms, and appropriate epinephrine administration is essential for patients and their families 1.

Overall, the management of severe allergic reactions prioritizes prompt epinephrine administration, followed by supportive care and education on prevention and emergency response, as supported by the latest evidence 1.

From the FDA Drug Label

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 management of severe allergic reactions (anaphylaxis) involves the use of epinephrine (IM) for emergency treatment. Key points include:

• Emergency treatment is required for anaphylaxis
• Epinephrine (IM) is used for the treatment of anaphylaxis
• The signs and symptoms of anaphylaxis include:
  • Flushing
  • Apprehension
  • Syncope
  • Tachycardia
  • Hypotension
  • Convulsions
  • Vomiting
  • Diarrhea
  • Abdominal cramps
  • Involuntary voiding
  • Airway swelling
  • Laryngospasm
  • Bronchospasm
  • Pruritus
  • Urticaria or angioedema
  • Swelling of the eyelids, lips, and tongue 2

From the Research

Management of Severe Allergic Reactions (Anaphylaxis)

The management of anaphylaxis involves the administration of epinephrine, which is the mainstay of acute pharmacotherapy for this complication 3. The method of choice for administering epinephrine is by intramuscular injection with an autoinjector, which is mainly done to treat reactions of intermediate severity 3.

Administration of Epinephrine

• The injection is given in the lateral portion of the thigh and can be repeated every 10-15 minutes until there is a response 3.
• The dose to be administered is 300-600 µg for an adult or 10 µg/kg for a child 3.
• Epinephrine should be administered promptly once anaphylaxis is suspected, to minimize morbidity and mortality 4.

Carriage and Use of Epinephrine Autoinjectors

• Most patients (89%) fill their epinephrine autoinjector (EAI) prescriptions, but only 44% carry at least one EAI "all the time" and 24% carry multiple EAIs 5.
• Sixty-five percent of respondents reported a personal history of EAI use, but most adults (52%) reported that an EAI was not used, although it would have been beneficial during their most severe allergic reaction 5.
• All patients at risk for anaphylaxis should carry 2 epinephrine autoinjectors and be taught and able to demonstrate how to use them 4.

Challenges and Future Directions

• Current anaphylaxis management practices are suboptimal, but could be facilitated through lowering EAI-related out-of-pocket costs and improving patient education efforts 5.
• Personalized EAI selection is influenced by intrinsic individual factors, extrinsic factors such as the properties of the individual EAI, as well as cost and coverage 6.
• Despite clear recommendations, only a small proportion of anaphylaxis incidents are treated with epinephrine, and there is a need for further research on cardiovascular involvement in anaphylaxis and on potential new therapeutic approaches 3, 7.