Anaphylaxis

Anaphylaxis is highly likely with acute skin or mucosal involvement plus respiratory compromise or hypotension/end-organ symptoms; with rapid involvement of at least two systems after a likely allergen; or with hypotension after a known allergen. For adults, hypotension is systolic blood pressure below 90 mm Hg or a decrease greater than 30% from baseline. PubMedPubMedA Clinical Practice Guideline for the Emergency Management of Anaphylaxis (2020)

Absence of hives or angioedema does not exclude anaphylaxis. This is particularly important in perioperative reactions, where cardiovascular and respiratory compromise may predominate, and in patients with abrupt bronchospasm, laryngeal symptoms, or hypotension after a probable exposure. BMJ+1BMJAnaphylaxis - Symptoms, diagnosis and treatment | BMJ Best Practice USPubMedRecent update on the management of anaphylaxis

Treat the clinical syndrome rather than waiting for confirmatory testing. Serum tryptase may support retrospective confirmation, but it lacks sensitivity and should not alter immediate resuscitation. Paired acute and baseline samples are more informative than a single value; one review describes acute sampling between 30 minutes and 2 hours after symptom onset and baseline sampling at least 24 hours after complete resolution. PubMedPubMedRecent update on the management of anaphylaxis

Use epinephrine 1 mg/mL IM in the anterolateral thigh. FDA labeling supports 0.3-0.5 mg for adults and children weighing 30 kg or more, and 0.01 mg/kg for children under 30 kg, with a maximum 0.3 mg per injection; repeat every 5-10 minutes as clinically necessary. The thigh is preferred because of its size and blood flow. dailymed nlm nih+1dailymed nlm nihDailyMed - ADRENALIN- epinephrine injectiondailymed nlm nihThese highlights do not include all the information needed to use EPINEPHRINE INJECTION safely and effectively. See full prescribing information for EPINEPHRINE INJECTION. EPINEPHRINE injection, for intravenous, intramuscular, subcutaneous useInitial U.S. Approval: 1939

There are no absolute contraindications to epinephrine for life-threatening anaphylaxis. Cardiovascular disease, advanced age, hypertension, and beta-blocker treatment warrant monitoring but should not delay IM treatment. IV bolus epinephrine has substantially greater risk of overdose and cardiovascular complications than IM administration and should not be routine initial therapy outside monitored expert settings. dailymed nlm nih+2dailymed nlm nihDailyMed - ADRENALIN- epinephrine injectionPubMedA Clinical Practice Guideline for the Emergency Management of Anaphylaxis (2020)PubMedManagement of Refractory Anaphylaxis: An Overview of Current Guidelines

Position patients supine when circulatory compromise is present; patients with prominent respiratory distress may require a more upright position. Continuously reassess mental status, airway, respiratory effort, oxygenation, blood pressure, and perfusion. PubMed+1PubMedA Clinical Practice Guideline for the Emergency Management of Anaphylaxis (2020)PubMedManagement of Refractory Anaphylaxis: An Overview of Current Guidelines

Definitions vary, but contemporary guidance commonly treats failure to respond adequately after 2 doses of IM epinephrine as a trigger for escalation; a U.S. expert consensus definition uses three or more appropriate epinephrine doses or initiation of IV infusion in addition to symptom-directed management. PubMedPubMedManagement of Refractory Anaphylaxis: An Overview of Current Guidelines

Reassess for continued allergen exposure, inadequate IM delivery, airway obstruction, profound distributive shock, and competing diagnoses. Give additional IM epinephrine while mobilizing critical-care support, providing airway management, and administering rapid IV crystalloid. PubMedPubMedManagement of Refractory Anaphylaxis: An Overview of Current Guidelines

For persistent cardiovascular compromise despite appropriate IM epinephrine and fluids, most reviewed guidelines recommend titrated IV epinephrine infusion with close cardiopulmonary monitoring. The optimum infusion regimen and preferred add-on vasopressor remain uncertain because high-quality comparative data are lacking. PubMedPubMedManagement of Refractory Anaphylaxis: An Overview of Current Guidelines

Biphasic anaphylaxis is recurrence after apparent resolution without re-exposure. Reported incidence varies substantially because of differing definitions; a recent case-based review cites 0.4% to 23.3%, with many datasets suggesting approximately 4%-6%. BMJBMJMultiphasic anaphylaxis in the emergency and intensive care setting | BMJ Case Reports

Observation duration should reflect initial severity, response to treatment, need for repeated epinephrine, hypotension, persistent symptoms, asthma or other respiratory disease, access to emergency care, and ability to recognize and treat recurrence. Severe, protracted, multiphasic, or refractory reactions require extended monitored care or admission. BMJ+2BMJMultiphasic anaphylaxis in the emergency and intensive care setting | BMJ Case ReportsPubMedA Clinical Practice Guideline for the Emergency Management of Anaphylaxis (2020)PubMedManagement of Refractory Anaphylaxis: An Overview of Current Guidelines

The evidence base does not yield a single universally validated observation interval. A guideline reviewed in the supplied literature recommends at least 12 hours of hospital monitoring after symptom relief, particularly for patients with hypotension, whereas other sources describe shorter risk-stratified observation for uncomplicated cases. PubMed+1PubMedA Clinical Practice Guideline for the Emergency Management of Anaphylaxis (2020)PubMedManagement of Refractory Anaphylaxis: An Overview of Current Guidelines

Refer patients after suspected anaphylaxis to an allergy service for trigger assessment, counseling, and prevention planning. Referral is especially important for an uncertain trigger, drug-associated reaction, venom reaction, perioperative event, or recurrent/idiopathic anaphylaxis. nice org uk+1nice org ukOverview | Anaphylaxis: assessment and referral after emergency treatment | Guidance | NICEPubMedEvaluating the management of anaphylaxis in US emergency departments: Guidelines vs. practice

Prescribe epinephrine autoinjector therapy and provide practical demonstration. Counseling should include recognition of respiratory and circulatory symptoms, immediate epinephrine use, emergency activation, avoidance of suspected triggers pending evaluation, and awareness that symptoms may recur after an initial response. dailymed nlm nih+2dailymed nlm nihDailyMed - ADRENALIN- epinephrine injectiondailymed nlm nihThese highlights do not include all the information needed to use EPINEPHRINE INJECTION safely and effectively. See full prescribing information for EPINEPHRINE INJECTION. EPINEPHRINE injection, for intravenous, intramuscular, subcutaneous useInitial U.S. Approval: 1939PubMedA Clinical Practice Guideline for the Emergency Management of Anaphylaxis (2020)

Review the medication list and document the suspected culprit with the clinical phenotype and timing, rather than applying an imprecise allergy label. For drug-induced anaphylaxis, report the event through appropriate pharmacovigilance systems and arrange formal allergy evaluation when future use may be clinically important. PubMed+1PubMedA Clinical Practice Guideline for the Emergency Management of Anaphylaxis (2020)nice org ukOverview | Anaphylaxis: assessment and referral after emergency treatment | Guidance | NICE