Anaphylaxis Treatment

Prevention and Management

Recognize anaphylaxis symptoms, including skin manifestations, respiratory symptoms, cardiovascular symptoms, and/or gastrointestinal symptoms, as soon as possible, as recommended by the American Academy of Pediatrics and the American Academy of Allergy, Asthma, and Immunology 1, 2
Identify high-risk factors for biphasic anaphylaxis, including severe initial anaphylactic reaction, requirement of more than one dose of epinephrine, wide pulse pressure, unknown anaphylaxis trigger, cutaneous signs and symptoms, and drug trigger in children, as identified by the American Academy of Allergy, Asthma, and Immunology 3
The American Academy of Allergy, Asthma, and Immunology recommends that antihistamines and corticosteroids should not be used as first-line treatment for anaphylaxis and should not delay the administration of epinephrine 3
The use of glucocorticoids or antihistamines to prevent biphasic anaphylaxis is not recommended, as their significant benefit has not been proven 3
The use of antihistamine and/or glucocorticoid premedication to prevent contrast media anaphylaxis is unlikely to provide significant benefit in patients receiving low or iso-osmolar, non-ionic contrast media agents 3

Administer epinephrine via intramuscular injection in the mid-outer thigh (vastus lateralis) with a dose of:
The recommended epinephrine dosage guidelines are:

Patient Category	Epinephrine Dose	Concentration	Volume
Adults and children ≥30 kg	0.3-0.5 mg	1:1000 (1 mg/mL)	0.3-0.5 mL
Children <30 kg	0.01 mg/kg (max 0.3 mg)	1:1000 (1 mg/mL)	0.01 mL/kg (max 0.3 mL)	[5]

Repeat epinephrine every 5-15 minutes if symptoms persist or worsen, as recommended by the American Academy of Pediatrics and the American Academy of Allergy, Asthma, and Immunology 1, 2
Delayed epinephrine administration is associated with increased mortality, and epinephrine should never be delayed while administering secondary medications, as recommended by the American Academy of Pediatrics 1
There are no absolute contraindications for epinephrine use in anaphylaxis, even in patients with cardiovascular disease, as stated by the American Academy of Allergy, Asthma, and Immunology 2

Establish and maintain airway, administer oxygen at 6-8 L/min, and monitor for signs of airway compromise, with endotracheal intubation may be necessary in severe cases, as recommended by the American Academy of Allergy, Asthma, and Immunology 2
Provide supplemental oxygen for patients with respiratory symptoms or those receiving multiple doses of epinephrine, as recommended by the American Academy of Allergy, Asthma, and Immunology 6, 5, 7, 2, 8
Albuterol 2.5-5 mg via nebulizer may be used for persistent bronchospasm, as recommended by the American Academy of Allergy, Asthma, and Immunology and the American Academy of Otolaryngology-Head and Neck Surgery 3, 7, 2

Establish intravenous access and administer normal saline for fluid replacement, with 1-2 L may be required for adults, and consider dopamine for refractory hypotension, as recommended by the American Academy of Allergy, Asthma, and Immunology 2
Administer fluid resuscitation immediately for patients with hypotension, as recommended by the American College of Radiology 8, 9
Position patients with hypotension in a supine position with legs elevated, or in the Trendelenburg position for severe hypotension, as recommended by the American College of Radiology 8, 9

Administer corticosteroids (IV methylprednisolone 125 mg) for angioedema associated with IV alteplase, as recommended by the American Heart Association 10
H2 blockers (ranitidine 50 mg IV or famotidine 20 mg IV) may be administered for angioedema associated with IV alteplase, as recommended by the American Heart Association 10
H1 antihistamines, such as diphenhydramine 25-50 mg, may be administered for cutaneous symptoms, and H2 blockers, such as famotidine 20 mg IV, may be added for urticaria, as suggested by the American Academy of Allergy, Asthma, and Immunology and the American Society of Hematology 11, 3, 7, 2, 9, 12

Epinephrine is not recommended as primary treatment for hereditary angioedema (HAE), as stated by the American Academy of Allergy, Asthma, and Immunology 13
For hereditary angioedema, fresh frozen plasma, C1 esterase inhibitor, or icatibant (30 mg subcutaneously) may be more effective than epinephrine, as recommended by the American Heart Association and the American Academy of Allergy, Asthma, and Immunology 10, 13

Monitor patients closely for at least 4-6 hours for potential biphasic reactions, with preparation for a second dose of epinephrine if symptoms persist or worsen, as recommended by the American Academy of Pediatrics 1
Patients should be observed until signs and symptoms have fully resolved, with a strength of evidence level of high, and high-risk patients should have extended observation of up to 6 hours or longer, including hospital admission, as recommended by the American College of Radiology and the American Academy of Allergy, Asthma, and Immunology 3, 6, 5, 7, 2, 8
Patients should be educated on the risk of biphasic reactions, signs and symptoms of anaphylaxis, proper use of epinephrine auto-injector, and importance of seeking immediate medical attention if symptoms recur, as recommended by the American Academy of Allergy, Asthma, and Immunology and the American College of Radiology, with a strength of evidence level of high 3, 8, 14, 15
Activate the emergency response system or call 911 in cases of anaphylaxis, as recommended by the American Heart Association, with a high level of evidence supporting early emergency response 16