2020 Anaphylaxis Updates

In January, a group from the American Academy of Allergy & Immunology published updated guidelines for anaphylaxis entitled “Anaphylaxis – a 2020 Practice Parameter Update, Systematic Review and GRADE Analysis.” The entire pre-print document was an impressive 135 pages long, so I decided to summarize it for you. (You’re welcome!)

 

First of all, the article provided an awesome visual graphic of the current criteria for anaphylaxis. While it’s pretty to look at and is very clear, it does not appear to be significantly different from the previously published guidelines for anaphylaxis from the National Institute of Allergy and Infectious Disease. I was unable to find any discernible differences from previously published guidelines in terms of the best way to determine whether anaphylaxis is occurring.

 

 

 

However, the review did update some key clinical advice in regard to anaphylaxis.

 

General suggestions include:

 

• Never delay the administration of epinephrine during anaphylaxis.
• Epinephrine should always be the first-line therapy, regardless of whether the reaction is the first one (uniphasic) or a delayed second (biphasic) reaction.
• All patients diagnosed and treated for anaphylaxis should be kept under careful observation by clinicians until all symptoms have fully resolved.
• All patients should be educated about anaphylaxis before leaving the medical provider. Specifically, they should be educated about self-injectable epinephrine, risk of recurrence, trigger avoidance, & threshold considerations for further care. All patients should be referred to an allergist for follow-up.
• Patients who have severe anaphylaxis and/or the need for more than one dose of epinephrine should be under extended medical observation as they are more likely to have a biphasic reaction.

 

Regarding biphasic anaphylaxis:

 

• A biphasic reaction is a two-phase anaphylactic event that occurs after the anaphylaxis is treated and the symptoms resolve. Even when the trigger has been removed and the patient is not re-exposed to the allergen, some patients can have a delayed second reaction that can be less severe, similar, or even more severe than the first reaction.
• In addition to having a severe reaction and/or the need for multiple epinephrine injections, patients more at risk for a biphasic reaction include those who experience cutaneous signs and symptoms, unknown anaphylaxis triggers, drug triggers in children, and wide pulse pressure.
• The researchers note, “Antihistamines and/or glucocorticoids are not reliable interventions to prevent biphasic anaphylaxis but may be considered as secondary treatment.”

 

On premedication, based on the evidence:

 

• The authors noted, “Although we suggest against the use of antihistamines and/or glucocorticoids as an intervention to prevent biphasic anaphylaxis, these may be considered for the secondary treatment of anaphylaxis. In particular, antihistamines may treat urticaria and itching to improve comfort during anaphylaxis, but if used prior to epinephrine administration, antihistamine administration could lead to a delay in first-line treatment of anaphylaxis.”
• Premedication with antihistamines and/or glucocorticoids appears to be effective in patients undergoing chemotherapy infusion and rush allergen immunotherapy. The evidence supports that this practice provides value in reducing systemic reactions and anaphylaxis.
• Premedication with antihistamines and/or glucocorticoids does not appear to be effective for patients receiving low- or iso-osmolar radiocontrast material.
• The authors concluded that certain circumstances (beyond chemo and allergy immunotherapy) do warrant premedication based on clinical judgment. Specifically, they noted, “Clinicians may reasonably consider premedication in clinical circumstances associated with a high level of perceived risk of anaphylaxis or comorbidities associated with greater anaphylaxis fatality risk (such as underlying cardiovascular disease, use of beta-blockers, or prior severe anaphylaxis), although evidence is lacking to clearly support this practice.

 

Reference

Shaker MS, Wallace DV, Golden DB, Oppenheimer J, Bernstein JA, Campbell RC, Dinakar C, Ellis A, Greenhawt M, Khan DA, Lang DM, Lang ES, Lieberman JA, Portnoy J, Rank MA, Stukus DR, Wang J, Collaborators, Riblet N, Bobrownicki A, Bontrager T, Dusin J, Foley J, Frederick B, Fregene E, Hellerstedt S, Hassan F, Hess K, Horner C, Huntington K, Kasireddy P, Keeler D, Kim B, Lieberman P, Lindhorst E, McEnany F, Milbank J, Murphy H, Pando O, Patel A, Ratliff N, Rhodes R, Robertson K, Scott H, Snell A, Sullivan R, Trivedi V, Wickham A, Anaphylaxis – a 2020 Practice Parameter Update, Systematic Review and GRADE Analysis, Journal of Allergy and Clinical Immunology (2020), doi: https://doi.org/10.1016/j.jaci.2020.01.017.