Management of Mild to Moderate Allergic Reactions

Assessment and Treatment

The American Academy of Allergy, Asthma, and Immunology recommends immediate assessment for anaphylaxis in patients with multi-system involvement, and treatment with intramuscular epinephrine if anaphylaxis is suspected 1, 3
For patients with skin-only symptoms, the American Academy of Allergy, Asthma, and Immunology suggests antihistamine-based treatment, such as diphenhydramine 25-50 mg orally or IV, as the primary treatment 2, 4
The American Academy of Pediatrics recommends administering H1 antihistamine, such as diphenhydramine, as the primary treatment for isolated cutaneous symptoms, with an alternative option being cetirizine 10 mg orally for less sedation with comparable onset 3, 4
The American Academy of Allergy, Asthma, and Immunology recommends adding H2 antihistamine, such as ranitidine 75-150 mg orally or IV, for enhanced effect in patients with skin-only symptoms 2, 3

The American Academy of Allergy, Asthma, and Immunology suggests observing patients for a minimum of 4-6 hours after symptom resolution, monitoring specifically for progression to respiratory symptoms, development of hypotension or cardiovascular symptoms, and recurrence of skin symptoms suggesting biphasic reaction 1, 4
The American Academy of Pediatrics recommends prescribing a 2-3 day course of diphenhydramine, H2 antihistamine, and prednisone for patients with mild to moderate allergic reactions 4

The American Heart Association recommends that patients on beta-blockers may require glucagon 1-2 mg IV as a rescue medication if epinephrine fails, as epinephrine may be less effective in these patients 3
The American Academy of Allergy, Asthma, and Immunology suggests that epinephrine is safe and indicated for pregnant patients, as maternal hypoxia poses a greater fetal risk than epinephrine 3