Anaphylaxis Clinical Pathway — Emergency Department

Adjunctive Medications

Antihistamines (H1) relieve the symptoms, hives/itch, but do not relieve severe symptoms.
Addition of antihistamine (H2) may provide more symptomatic relief for pruritis and abdominal symptoms.

Antihistamines

Medication

Route

mg/kg

Max Dose

Comments

Diphenhydramine

IV/PO

50 mg

Cetirizine

10 mg

6-23 months
2-5 years
> 6 years

2.5 mg/day
2.5-5 mg/day
5-10 mg/day

Famotidine

IV
PO

0.25
0.5

20 mg
40 mg

Administer IV over 2 minutes

Steroids

For patients who respond well to epinephrine, the addition of steroids may not be necessary unless used to treat airway or respiratory disease. There is some thought that it may decrease the risk of biphasic reactions; however a 2020 systematic review failed to document a benefit.

Reference:

Anaphylaxis-a 2020 practice parameter update, systematic review, and Grading of Recommendations, Assessment, Development and Evaluation (GRADE) analysis.

Medication	Route	mg/kg	Max Dose	Comments
Methylprednisolone	IV	2	125 mg
Prednisone	PO	2	60 mg
Dexamethasone	PO	0.6	8 mg	Prednisone alternative No second dose required

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The clinical pathways are based upon publicly available medical evidence and/or a consensus of medical practitioners at The Children’s Hospital of Philadelphia (“CHOP”) and are current at the time of publication. These clinical pathways are intended to be a guide for practitioners and may need to be adapted for each specific patient based on the practitioner’s professional judgment, consideration of any unique circumstances, the needs of each patient and their family, and/or the availability of various resources at the health care institution where the patient is located.

Accordingly, these clinical pathways are not intended to constitute medical advice or treatment, or to create a doctor-patient relationship between/among The Children’s Hospital of Philadelphia (“CHOP”), its physicians and the individual patients in question. CHOP does not represent or warrant that the clinical pathways are in every respect accurate or complete, or that one or more of them apply to a particular patient or medical condition. CHOP is not responsible for any errors or omissions in the clinical pathways, or for any outcomes a patient might experience where a clinician consulted one or more such pathways in connection with providing care for that patient.