Anaphylaxis Management Guidelines

Immediate Treatment

The American Academy of Allergy, Asthma, and Immunology recommends intramuscular epinephrine as the first-line treatment for anaphylaxis and severe allergic reactions in both outpatient and inpatient settings, which must be administered immediately without delay 1, 2
The American College of Allergy, Asthma, and Immunology suggests that adults and children over 25 kg should receive 0.3 mg epinephrine autoinjector IM into the anterolateral thigh 1
The American Academy of Pediatrics recommends that children between 10-25 kg should receive 0.15 mg epinephrine autoinjector IM into the anterolateral thigh 1
Alternative dosing for epinephrine is 1:1,000 solution at 0.01 mg/kg per dose IM (maximum 0.5 mg per dose) 1
Repeat doses of epinephrine should be administered every 5-15 minutes as needed if symptoms persist or progress 1, 2

The American Academy of Allergy, Asthma, and Immunology recommends administering H1 antihistamine (Diphenhydramine) at 1-2 mg/kg per dose, maximum 50 mg IV or oral, simultaneously with epinephrine 1, 2
The British Society for Allergy and Clinical Immunology suggests that bronchodilators (Albuterol) should be used for wheezing or bronchospasm, with dosing of 4-8 puffs (child) or 8 puffs (adult) via MDI, or 1.5 mL (child) or 3 mL (adult) via nebulizer every 20 minutes or continuously 1, 3
The American Heart Association recommends supplemental oxygen for any respiratory distress 1
The American College of Emergency Physicians suggests IV fluids for orthostasis, hypotension, or incomplete response to epinephrine, with large volume boluses of 10-20 mL/kg, repeated as needed 1, 3

The British Journal of Anaesthesia recommends that first-line treatment remains epinephrine IM, with the same dosing as the outpatient setting initially 1, 4
For refractory hypotension, the American College of Cardiology suggests considering continuous IV epinephrine infusion with continuous non-invasive blood pressure and heart rate monitoring 1, 5
Alternative routes for epinephrine administration, if IM is unavailable, include endotracheal or intra-osseous routes 1

The American Academy of Allergy, Asthma, and Immunology recommends that all patients who receive epinephrine must be observed for 4-6 hours minimum, longer for severe reactions 1, 3
The observation period should be extended to 12 hours for severe initial reactions, history of biphasic reactions, delayed epinephrine administration, or ongoing symptoms despite treatment 1, 2, 3

The American Academy of Allergy, Asthma, and Immunology suggests prescribing two epinephrine auto-injectors with hands-on training at discharge 1, 2
A written anaphylaxis emergency action plan, medical identification jewelry or wallet card, and continuation of adjunctive medications for 2-3 days are also recommended 1
The American College of Allergy, Asthma, and Immunology recommends follow-up appointments with primary care physicians and allergists/immunologists 1, 2

The American Heart Association recommends that patients on beta-blockers may have reduced response to epinephrine and should have glucagon readily available 2, 6
The American College of Cardiology suggests that epinephrine is still indicated for patients with cardiovascular disease, with serious adverse effects being rare in otherwise healthy individuals 2, 3

The American Academy of Allergy, Asthma, and Immunology recommends H1-antihistamines like diphenhydramine as second-line adjunctive therapy in anaphylaxis management, administered simultaneously with or immediately following epinephrine, with a recommended dose of 1-2 mg/kg per dose (maximum 50 mg) IV or oral for food-induced anaphylaxis 7, 8
Diphenhydramine provides symptomatic relief of urticaria and pruritus that commonly occur during anaphylaxis, although it does not reverse the life-threatening cardiovascular or respiratory manifestations of anaphylaxis 9, 10

The combination of H1 and H2 antihistamines is emerging as important in preventing severe cardiac deficits during anaphylaxis, with the NIAID guidelines recommending continuing H1 antihistamines (diphenhydramine every 6 hours) along with H2 antihistamines (ranitidine twice daily) for 2-3 days post-discharge to prevent biphasic reactions 7, 8, 11
The use of antihistamines and corticosteroids in preventing biphasic reactions is based on low-certainty evidence, but their use remains standard practice for symptom control, with the 2020 JACI practice parameter acknowledging their potential benefit for treating urticaria and pruritus during anaphylaxis 9, 10

Antihistamines should never delay or replace epinephrine administration, as epinephrine remains the only first-line medication for anaphylaxis, and patients receiving epinephrine must be observed for 4-6 hours minimum, with longer observation (up to 12 hours) for severe reactions 9, 10