Anaphylaxis

Publication Date: December 17, 2023
Last Updated: October 28, 2024

Diagnosis

Recommendation 1 (CBS)

We recommend obtaining a baseline serum tryptase (bST) in patients presenting with a history of recurrent, idiopathic, or severe anaphylaxis, particularly those presenting with hypotension.

(S, M )
620

Recommendation 2 (CBS) 

We suggest drawing an acute-phase tryptase level as early as possible during a suspected anaphylactic event (ideally within 2 hours after onset of symptoms). We suggest drawing a second tryptase measurement at a later time as a baseline for comparison to determine whether there was a significant acute elevation.

(C, M )
620

Recommendation 3 (CBS)

We suggest clinicians consider evaluation for hereditary α-tryptasemia (HαT) in patients with elevated bST level (8 ng/mL or greater). (C, L )
620

Recommendation 4 (CBS)

We suggest clinicians consider evaluation for mastocytosis, including a bone marrow biopsy, for adult patients with severe insect sting anaphylaxis or recurrent idiopathic anaphylaxis (IA), particularly those with a predictive Red Espanola MAstocitosis (REMA) score.

(C, M )
620

Recommendation 5 (CBS)

We suggest that clinicians consider alpha-gal allergy as a possible cause of recurrent IA in a patient with history of possible tick bite; when appropriate, check an alpha-gal immunoglobulin E (IgE) and advise a trial elimination of mammalian meat if alpha-gal IgE sensitization is detected.

(C, M )
620

Recommendation 6 (CBS)

We suggest that meeting diagnostic criteria for anaphylaxis is not required before the use of epinephrine.

(C, VL )
620

Recommendation 7 (CBS)

We suggest that neither the clinical decision to administer epinephrine, nor the clinical response to epinephrine, be used as a surrogate marker to establish a diagnosis of anaphylaxis. (C, VL )
620

Infants and Toddlers

Anaphylaxis in Infants and Toddlers

Recommendation 8 (CBS)

We suggest that clinicians use current NIAID/FAAN or WAO anaphylaxis criteria to assist in the diagnosis of anaphylaxis in infants/toddlers, because there are no criteria specific to this age group.

(C, L )
620

Recommendation 9 (CBS)

We suggest clinicians be aware that, in infants and toddlers, patient age does not correlate with reaction severity.

(C, VL )
620

Recommendation 10 (CBS)

We suggest clinicians be aware that anaphylaxis is unlikely to be the initial reaction to a food or medication on first exposure in infants. (C, L )
620

Recommendation 11 (CBS)

We suggest clinicians be aware that parents of infants and toddlers may report age-specific symptoms that are less often reported by older children and adults.

(C, VL )
620

Recommendation 12 (CBS)

We suggest clinicians prescribe either the 0.1 mg or the 0.15 mg EAI dose for infants/toddlers weighing less than 15 kg.

(C, L )
620

Anaphylaxis in Community Settings

Recommendation 13 (CBS)

We recommend clinicians counsel patients at high risk of anaphylaxis to always carry self-injectable epinephrine and teach patients proper indications and use. (S, VL )
620

Recommendation 14 (CBS)

We recommend clinicians educate patients on avoidance of potential exposure to their allergen(s).

(S, VL )
620

Recommendation 15 (CBS)

We recommend clinicians educate patients that the main route of food-induced anaphylaxis is by ingestion and not contact or inhalation.

(S, M )
620

Anaphylaxis in Childcare Centers and Schools

Recommendation 16 (GRADE)

We suggest childcare centers and schools implement staff training for allergy and anaphylaxis management.

(C, VL )
620

Recommendation 17 (GRADE)

We suggest that childcare centers and schools not implement site-wide food-specific prohibition because current research does not support consistent benefits. Special circumstances: It might be appropriate to implement allergen-restricted zones (e.g., milk-free table) when there are children who lack the capacity to self-manage.

(C, VL )
620

Recommendation 18 (GRADE)

We suggest that childcare centers and schools stock undesignated EAIs that can be used to treat any individual on school grounds who experiences anaphylaxis. (C, VL )
620

Anaphylaxis in the Restaurant Setting

Recommendation 19 (CBS)

We suggest clinicians counsel patients that although US regulations require disclosure of major allergens on labels of prepackaged foods, they do not require restaurants to declare ingredients or provide allergy warnings for non-prepackaged foods.

(C, VL )
620

Recommendation 20 (CBS)

We suggest clinicians counsel patients on safe practices for dining outside of the home.

(C, VL )
620

Anaphylaxis in Community Recreational Settings

Recommendation 21 (CBS)

We suggest that advising individuals at risk of anaphylaxis to wear or carry medical identification (e.g., jewelry or wallet card) be considered optional. If it is worn or carried, the wording on medical alert jewelry or wallet cards should be verified for accuracy by a health care professional. (C, VL )
620

Stock Epinephrine in Community Settings

Recommendation 22 (CBS)

We suggest that keeping stock EAI in community settings be encouraged, if feasible.

(C, VL )
620

Epinephrine Autoinjectors

Epinephrine Autoinjectors: When and What to Prescribe

Recommendation 23 (CBS)

We suggest clinicians routinely prescribe EAIs to patients at higher risk of anaphylaxis. When deciding whether to prescribe EAIs to lower risk patients, we suggest that clinicians engage in a shared decisionmaking process that considers the patients’ risk factors, values, and preferences.

(C, VL )
620

Recommendation 24 (CBS)

We suggest that in jurisdictions where single-packs of EAIs are available, clinicians consider a patient's risk factors for severe anaphylaxis, their values and preferences, and contextual factors when deciding whether to prescribe only one vs multiple EAIs. We suggest that they routinely prescribe more than 1 EAI when patients have previously required multiple doses of epinephrine to treat an episode of anaphylaxis and/or have a history of biphasic reactions.

(C, VL )
620

Recommendation 25 (CBS)

We suggest that clinicians counsel patients and caregivers to give epinephrine at the first sign of suspected anaphylaxis. We suggest that, in general, clinicians counsel patients or caregivers not to give epinephrine preemptively to an asymptomatic patient.

(C, VL )
620

Recommendation 26 (CBS)

We suggest that clinicians counsel patients that immediate activation of emergency medical services (EMS) may not be required if the patient experiences prompt, complete, and durable response to treatment with epinephrine, provided that additional epinephrine and medical care are readily available, if needed. We suggest that clinicians counsel patients to always activate EMS after epinephrine use if anaphylaxis is severe, fails to resolve promptly, fails to resolve completely or nearly completely, or returns or worsens after a first dose of epinephrine.

(C, VL )
620

Recommendation 27 (CBS)

Serious adverse reactions to intramuscular epinephrine are very rare and should not pose a barrier to the prescription or early administration of EAIs when indicated. To manage the risk of adverse events, we recommend that clinicians counsel patients and caregivers on the proper use of EAIs, the common adverse effects, and the need for immediate evaluation and treatment when signs or symptoms of serious adverse events develop.

(S, L )
620

Recommendation 28 (CBS)

We suggest that clinicians discuss the potential financial and psychosocial burdens of EAIs with patients while engaging in shared decision-making.

(C, VL )
620

Recommendation 29 (CBS)

When deciding which EAI to prescribe, we suggest that clinicians consider dosage, needle length, affordability, access, and patient treatment preferences. (C, VL )
620

Recommendation 30 (CBS)

During visits with patients who have been prescribed EAIs, we recommend that clinicians routinely review the essentials of EAI carriage, storage, and use; encourage patients to regularly practice EAI administration with a trainer device; and discuss strategies to manage barriers to adherence that patients may have experienced.

(S, L )
620

Beta-blockers and ACEIs

Stinging Insect Allergy and Venom Immunotherapy

Recommendation 31 (CBS)

We suggest that patients with a history of insect sting anaphylaxis who are not receiving VIT may continue BB or ACEI medications when the medical necessity of the daily medication outweighs the chance of increased severity of anaphylaxis to a sting.

(C, L )
620

Recommendation 32 (CBS)

We suggest that VIT may be prescribed for patients with a history of insect sting anaphylaxis who are treated with BB or ACEI medication, with shared decision-making regarding the benefits and potential harms of concurrent VIT treatment and medication, compared with withholding either the treatment or the medication. (C, L )
620

Recommendation 33 (CBS)

We suggest, in most cases, treatment with BB or ACEI medication need not be changed or discontinued in patients receiving maintenance VIT.

(C, M )
620

Allergen Immunotherapy

Recommendation 34 (CBS)

We suggest use of initial AIT may be considered in patients who are treated with BB or ACEI medication, with shared decision-making. It would be preferable to replace the BB or ACEI, if there is a safe and effective alternative.

(C, L )
620

Recommendation 35 (CBS)

We suggest that patients receiving maintenance dose AIT have a minimal increased risk of a severe anaphylactic reaction when on BB/ACEI medication and may consider continuing AIT and medications based on shared decision-making.

(C, L )
620

Planned Procedures: (e.g., Drug Desensitization, Radiocontrast Media [RCM] Administration, Intravenous Immunoglobulin Infusion)

Recommendation 36 (CBS)

For planned procedures (e.g., RCM, challenge/desensitization, and infusion) if the BB/ACEI medication cannot be safely interrupted, we suggest shared decision-making discussion of the medical necessity (benefit) of the procedure, the relative risk of anaphylaxis, the possibility of more severe reaction if the medication is continued, and the risk of stopping the medication. (C, VL )
620

Patients at Risk for Anaphylaxis (Unplanned Exposure or Unknown Cause)

Recommendation 37 (CBS)

We suggest that all patients at significant risk for recurrent and unexpected anaphylaxis (e.g., those with severe food allergy, mastocytosis or MCAS, or recurrent IA) be counseled about the risk of more severe anaphylaxis, and consider avoiding, where possible, the use of nonselective BBs or ACEIs.

(C, M )
620

Mast Cell Disorders

Recommendation 38 (CBS)

We recommend clinicians order a bone marrow biopsy with staining for tryptase, CD25 immunohistochemistry and flow cytometry, and the KIT D816V mutation when there is strong suspicion for systemic mastocytosis (SM).

(S, M )
620

Recommendation 39 (CBS)

We recommend clinicians not rely on serum tryptase levels alone for diagnostic assessment of the likelihood that a patient does or does not have a clonal mast cell disorder. (S, M )
620

Recommendation 40 (CBS)

We recommend measurement of bST in patients with severe insect sting anaphylaxis, particularly those who had hypotension and/or absence of urticaria; in all cases of recurrent unexplained anaphylaxis; and in patients with suspected mastocytosis.

(S, M )
620

Recommendation 41 (CBS)

We suggest clinicians consider evaluation for mastocytosis, including a bone marrow biopsy, for adult patients with severe insect sting anaphylaxis or recurrent IA, particularly those with a predictive REMA score. (C, M )
620

Recommendation 42 (CBS)

We suggest VIT be continued indefinitely in patients with mastocytosis and insect sting anaphylaxis due to the increased risk of severe or fatal sting anaphylaxis if VIT is discontinued.

(C, L )
620

Perioperative Anaphylaxis

Recommendation 43 (CBS)

We suggest that immediate hypersensitivity skin testing (percutaneous and intradermal) and/or in vitro-specific IgE testing be performed, when available, to all potential pharmacologic and nonpharmacologic culprits used during the perioperative period. If testing is not possible, we suggest referral to another center or, if necessary, use of the most efficacious agents structurally dissimilar from the most likely culprit. (C, VL )
620

Recommendation 44 (CBS)

We suggest that immediate hypersensitivity testing to suspected culprit (and alternative) agents be delayed after perioperative anaphylaxis (POA), unless repeat surgery cannot be postponed. If surgery with general anesthesia is needed sooner, then testing may be performed when needed. (C, VL )
620

Recommendation 45 (CBS)

We suggest that challenges be performed, when feasible, to all potential culprit agents to which skin and/or in vitro testing is negative, before or in conjunction with use of these agents for a future surgical procedure.

(C, VL )
620

Recommendation 46 (CBS)

We suggest that repeat anesthesia may proceed in the context of shared decision-making and as directed by history and results of diagnostic evaluation.

(C, L )
620

Recommendation 47 (CBS)

We suggest that avoidance of culprit pharmacologic and nonpharmacologic agents associated with POA may be considered, regardless of test results if challenge is not feasible and if equally efficacious, structurally unrelated alternatives are available.

(C, L )
620

Recommendation 48 (CBS)

We offer no recommendation for or against the use of pretreatment before return to the operating room in patients with negative cutaneous (percutaneous and intradermal) and/or in vitro-specific IgE testing (and challenge when possible) result to all suspected POA culprit agents.

(, VL )
620

Recommendation Grading

Abbreviations

  • ACEI: Angiotensin-converting Enzyme Inhibitor
  • AIT: Allergen Immunotherapy
  • BB:

    beta-blocker

  • EAI:

    epinephrine Autoinjector

  • EMS: Emergency Medical Services
  • HαT:

    hereditary α-tryptasemia

  • IA:

    idiopathic Anaphylaxis

  • MCAS: Mast Cell Activating Syndrome
  • NIAID: National Institute Of Allergy And Infectious Diseases
  • POA:

    perioperative Anaphylaxis

  • RCM: Radiocontrast Media
  • REMA:

    Red Espanola Mastocitosis

  • VIT:

    venom Immunotherapy

  • WAO:

    World Allergy Organization

  • bST: Baseline Serum Tryptase

Overview

Title

Anaphylaxis

Authoring Organizations

American College of Allergy, Asthma, and Immunology

American Academy of Allergy, Asthma & Immunology

Publication Month/Year

December 17, 2023

Last Updated Month/Year

November 7, 2024

Supplemental Implementation Tools

Document Type

Guideline

External Publication Status

Published

Country of Publication

US

Document Objectives

The purpose of this practice parameter is to evaluate current evidence and provide guidance to health care practitioners on the diagnosis and management of anaphylaxis. This updated practice parameter focuses on topics selected by the workgroup as described subsequently. By identifying knowledge gaps in the research literature, these guidelines may also help researchers to direct their attention to topics on which more studies are needed. This practice parameter is meant to update the selected topics and to complement our previous practice parameters on anaphylaxis but does not entirely replace or supersede those documents which may be consulted for additional background discussion on anaphylaxis and for guidance on topics not selected for review in the current update. T

Target Provider Population

Allergy/immunology specialists, health care providers who care for patients with anaphylaxis

PICO Questions

  1. What is the role of serum tryptase measurements in anaphylaxis diagnosis?

  2. In what settings should the clinician consider evaluation of alpha-gal allergy?

  3. Is the diagnosis of anaphylaxis required for administration of epinephrine?

  4. Is administration of, or response to, epinephrine necessary for the diagnosis of anaphylaxis?

  5. How should anaphylaxis be diagnosed in infants and toddlers?

  6. Should age of the infant/toddler experiencing anaphylaxis be used as a predictor of reaction severity?

  7. Should lack of prior exposure to an allergen be used as a predictor for anaphylaxis risk?

  8. Do infants and toddlers present with different signs and symptoms of anaphylaxis compared with older children and adults?

  9. Should infants/toddlers be prescribed the 0.1 mg or 0.15 mg EAI?

  10. What counseling and education should clinicians provide to patients to help them manage the risk of anaphylaxis in community settings?

  12. Should childcare centers and schools prohibit specific foods site wide (eg, nut-free schools), rather than not implement such restrictions?

  13. Should childcare centers and schools stock undesignated EAIs that can be used to treat any individual on school grounds who experiences anaphylaxis?

  14. What education should clinicians provide to patients with food allergy regarding anaphylaxis in the restaurant setting?

  15. Should clinicians advise use of medical identification (eg, jewelry or wallet card) for individuals at risk of anaphylaxis?

  16. Should stock epinephrine in community settings be supported?

  17. Should clinicians take a risk-stratified approach to EAI prescription?

  18. How many EAIs should clinicians prescribe to each patient?

  19. What is the optimal timing for EAI administration in relation to symptoms?

  20. When should EMS be activated after EAI use?

  21. What are the adverse events associated with EAI use?

  22. What are the burdens of EAI prescription?

  24. What counseling, education, and/or training on epinephrine should clinicians provide to patients and caregivers?

  25. Should BB or ACEI be discontinued or changed in patients with a history of insect sting anaphylaxis who are not yet on VIT?

  26. Should VIT be recommended to patients with a history of insect sting anaphylaxis who are treated with BBs or ACEIs?

  27. In patients on maintenance VIT who are treated with BBs or ACEIs, should VIT be stopped or the medication discontinued?

  28. Should patients who are treated with BB or ACEI medication initiate a course of AIT?

  29. In patients on maintenance AIT who are treated with BB or ACEI medication, should AIT be stopped or the medication discontinued?

  30. For planned procedures where there is a risk of anaphylaxis, should BB or ACEI treatment be interrupted or continued?

  31. In patients at significant risk for recurrent and unexpected anaphylaxis due to unplanned exposure or unknown cause, should BB or ACEI medication be stopped or continued?

  32. What is the role of bone marrow biopsy and serum tryptase level in evaluation of patients for possible mastocytosis?

  33. When should bST be measured?

  34. When should patients be evaluated for mastocytosis?

  35. Should patients with mastocytosis and insect sting allergy be treated with VIT?

  36. Should immediate hypersensitivity skin testing or in vitro testing be performed with all potential culprit pharmacologic and nonpharmacologic agents, or should this be limited to the agents that are highly suspected?

  37. Should immediate hypersensitivity skin and/or in vitro testing of suspected culprit (and alternative) agents be performed as soon as possible or delayed 4 to 6 weeks after the POA event?

  38. Should challenges be performed to potential POA pharmacologic and nonpharmacologic culprits to which skin and/ or in vitro testing is negative?

  39. Should patients with POA be advised to avoid repeat anesthesia?

  40. Should repeat anesthesia after POA be performed with equally efficacious, structurally unrelated alternatives rather than the suspected culprit agents with negative skin and/or in vitro test results when challenge is not feasible?

Inclusion Criteria

Male, Female, Adolescent, Adult, Child, Older adult

Health Care Settings

Ambulatory, Childcare center, Correctional facility, Emergency care, Home health, Hospital, Long term care, Medical transportation, Outpatient, School, Operating and recovery room

Intended Users

Athletics coaching, law enforcement, nurse, nurse practitioner, community pharmacist, physician, physician assistant

Scope

Treatment, Management, Prevention

Diseases/Conditions (MeSH)

D000707 - Anaphylaxis

Keywords

anaphylaxis, epinephrine

Source Citation

David B.K. Golden, Julie Wang, Susan Waserman, Cem Akin, Ronna L. Campbell, Anne K. Ellis, Matthew Greenhawt, David M. Lang, Dennis K. Ledford, Jay Lieberman, John Oppenheimer, Marcus S. Shaker, Dana V. Wallace, Elissa M. Abrams, Jonathan A. Bernstein, Derek K. Chu, Caroline C. Horner, Matthew A. Rank, David R. Stukus, Alyssa G. Burrows, Heather Cruickshank, David B.K. Golden, Julie Wang, Cem Akin, Ronna L. Campbell, Anne K. Ellis, Matthew Greenhawt, David M. Lang, Dennis K. Ledford, Jay Lieberman, John Oppenheimer, Marcus S. Shaker, Dana V. Wallace, Susan Waserman, Elissa M. Abrams, Jonathan A. Bernstein, Derek K. Chu, Anne K. Ellis, David B.K. Golden, Matthew Greenhawt, Caroline C. Horner, Dennis K. Ledford, Jay Lieberman, Matthew A. Rank, Marcus S. Shaker, David R. Stukus, Julie Wang, Anaphylaxis: A 2023 practice parameter update, Annals of Allergy, Asthma & Immunology, 2023, ISSN 1081-1206, https://doi.org/10.1016/j.anai.2023.09.015.

Supplemental Methodology Resources

Systematic Review Document, Data Supplement