Cleveland Clinic Journal of MedicineAnaphylaxis: Highlights from the Practice Parameter Update

Updated guidelines refine diagnostic criteria, treatment protocols, and preventive measures for anaphylaxis, with significant implications for managing severe allergic reactions and improving patient outcomes.

The updated practice parameter on anaphylaxis, collaboratively developed by the American Academy of Allergy, Asthma, and Immunology and the American College of Allergy, Asthma, and Immunology, provides comprehensive guidelines on diagnosing, treating, and preventing anaphylaxis. These guidelines emphasize the critical role of early epinephrine administration and outline new recommendations for monitoring and follow-up care to prevent recurrent anaphylactic episodes and improve patient education on trigger avoidance.

Key Points:

• First-line Therapy: Epinephrine remains the first-line treatment for anaphylaxis and should be administered immediately upon onset to reduce morbidity and mortality.
• Administration Protocol: Epinephrine should be administered intramuscularly in the mid-outer thigh at a dose of 0.01 mg/kg of a 1:1000 solution, with a maximum dose of 0.5 mg for adults and 0.3 mg for children.
• Observation for Biphasic Anaphylaxis: Patients with severe anaphylaxis should be monitored for biphasic anaphylaxis, which can occur up to 72 hours after the initial reaction.
• Second-line Medications: Beta-2 agonists, antihistamines, and corticosteroids are considered second-line treatments but do not replace epinephrine for managing cardiovascular symptoms.
• Risk Factors for Severe Anaphylaxis: Key risk factors include cardiovascular disease, asthma, older age, use of beta-blockers or ACE inhibitors, and systemic mastocytosis.
• Causes of Anaphylaxis: Medications and stinging insects are common triggers in adults, while foods and stinging insects are prevalent in children.
• Premedication Protocols: Premedication with antihistamines and glucocorticoids is recommended for certain chemotherapy protocols but is not definitively beneficial for preventing radiocontrast media reactions.
• Education and Follow-up: Patients should be educated on the use of self-injectable epinephrine and trigger avoidance. Follow-up care should involve an allergy and immunology specialist.
• Updated Diagnostic Criteria: The guidelines expand the criteria for diagnosing anaphylaxis, promoting early treatment even in cases where symptoms involve only a single organ system.
• Management Strategies: Immediate removal of the inciting allergen and provision of supportive care, including airway management and intravenous fluid resuscitation, are critical.
• Preventing Biphasic Reactions: No reliable interventions exist to prevent biphasic anaphylaxis; however, patients at higher risk should be observed for longer periods.
• Clinical Recommendations: The guidelines recommend GRADE analysis to evaluate the certainty of evidence, replacing the previous strength of recommendations and quality of evidence classification.
• Premedication for Allergen Immunotherapy: ACE inhibitors and beta-blockers should be discontinued when possible in patients receiving venom immunotherapy.

Recent publications show a global incidence of anaphylaxis between 50 and 112 episodes per 100,000 person-years while the estimated lifetime prevalence is 0.3–5.1%, variations depending on the definitions used, study methodology, and geographical areas. (World Allergy Organization Journal)

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