What is the protocol for managing an allergic reaction?

From the Guidelines

Managing an allergic reaction requires prompt recognition and appropriate intervention, with the most critical step being the immediate administration of epinephrine via an auto-injector for severe reactions or anaphylaxis, as recommended by the most recent and highest quality study 1. When an allergic reaction occurs, it is essential to assess the patient's airway, breathing, circulation, and skin, and call for help immediately.

• For mild to moderate reactions, an antihistamine like diphenhydramine (Benadryl) can be administered at 25-50mg for adults or 1mg/kg for children (up to 50mg) 1.
• For severe reactions or anaphylaxis, epinephrine should be administered via an auto-injector like EpiPen (0.3mg for adults, 0.15mg for children under 66 pounds) into the outer thigh, then call emergency services (911), as supported by 1 and 1. The epinephrine can be repeated after 5-15 minutes if symptoms persist, and the person should still go to the emergency room for observation, as symptoms can return 1. It is also crucial to remove the allergen if possible, have the person lie flat with legs elevated unless they're having breathing difficulties, in which case they should sit up, as recommended by 1. Epinephrine works by constricting blood vessels to increase blood pressure, relaxing airway muscles to improve breathing, and reducing inflammation, making it the primary medical therapy for anaphylaxis, as stated in 1. Anyone with known severe allergies should carry epinephrine auto-injectors at all times and wear medical identification, as emphasized by 1.

From the FDA Drug Label

2 DOSAGE & ADMINISTRATION Inject Adrenalin® intramuscularly or subcutaneously into the anterolateral aspect of the thigh, through clothing if necessary.

The injection may be repeated every 5 to 10 minutes as necessary Monitor the patient clinically for the severity of the allergic reaction and potential cardiac effects of the drug, with repeat doses titrated to effect Adults and Children 30 kg (66 lbs) or more: 0.3 to 0.5 mg (0.3 mL to 0. 5 mL) of undiluted Adrenalin® administered intramuscularly or subcutaneously in the anterolateral aspect of the thigh, up to a maximum of 0.5 mg (0.5 mL) per injection, repeated every 5 to 10 minutes as necessary. Children less than 30 kg (66 lbs): 0.01 mg/kg (0. 01 mL/kg) of undiluted Adrenalin® administered intramuscularly or subcutaneously in the anterolateral aspect of the thigh, up to a maximum of 0.3 mg (0.3 mL) per injection, repeated every 5 to 10 minutes as necessary.

The protocol for managing an allergic reaction involves administering epinephrine (IM) according to the following guidelines:

• Dosage:
  • Adults and children 30 kg (66 lbs) or more: 0.3 to 0.5 mg (0.3 mL to 0.5 mL)
  • Children less than 30 kg (66 lbs): 0.01 mg/kg (0.01 mL/kg)
• Administration: Intramuscularly or subcutaneously in the anterolateral aspect of the thigh
• Repeat doses: Every 5 to 10 minutes as necessary, titrated to effect, with monitoring for reaction severity and cardiac effects 2
• Indications: Emergency treatment of allergic reactions (Type I), including anaphylaxis 2

From the Research

Allergic Reaction Protocol

The protocol for managing an allergic reaction involves several steps, including:

• Removal of the trigger
• Early administration of intramuscular epinephrine 3, 4, 5
• Supportive care for the patient's airway, breathing, and circulation 4, 5
• Administration of adjunct medications, such as histamine H1 and H2 antagonists, corticosteroids, beta2 agonists, and glucagon, after epinephrine administration 5

Epinephrine Administration

Epinephrine is the mainstay of acute pharmacotherapy for anaphylaxis 3. The method of choice for administering epinephrine is by intramuscular injection with an autoinjector 3. The dose to be administered is 300-600 µg for an adult or 10 µg/kg for a child 3. Intravenous epinephrine should be used in patients in shock, either as a bolus or infusion, along with fluid resuscitation 4.

Adjunct Medications

The use of adjunct medications, such as antihistamines and corticosteroids, is controversial 6. Some studies suggest that antihistamines may be beneficial in anaphylaxis management 6, while others suggest that corticosteroid use should be revisited 6.

Monitoring and Disposition

Patients should be monitored for a biphasic reaction (i.e., recurrence of anaphylaxis without reexposure to the allergen) for four to 12 hours, depending on risk factors for severe anaphylaxis 5. Disposition depends on patient presentation and response to treatment 4. Mandatory observation periods are not necessary, because biphasic reactions are difficult to predict and may occur outside of typical observation periods 4.

Key Considerations

Key considerations in managing an allergic reaction include:

• Early recognition and treatment of anaphylaxis 3, 4, 5
• Use of epinephrine as the first-line treatment 3, 4, 5
• Supportive care for the patient's airway, breathing, and circulation 4, 5
• Administration of adjunct medications after epinephrine administration 5
• Monitoring for biphasic reactions and disposition based on patient presentation and response to treatment 4, 5