What is the treatment for an allergic reaction?

From the Guidelines

For severe allergic reactions (anaphylaxis), the first-line treatment is epinephrine administered intramuscularly in a dose of 0.01 mg/kg of a 1:1000 solution to a maximum of 0.5 mg in adults and 0.3 mg in children, as recommended by the most recent guidelines 1.

Key Considerations

• Epinephrine is the cornerstone of anaphylaxis management and should be administered promptly to prevent poor outcomes, including fatality 1.
• The ability of antihistamines and glucocorticoids to affect the outcome of anaphylaxis is unclear, but they may be used as adjunctive treatments 1.
• Biphasic anaphylaxis, which is recurrent anaphylaxis occurring 1 to 72 hours after resolution of an initial anaphylactic episode, is a potential complication, and patients should be monitored closely after an anaphylactic episode 1.

Treatment Approach

• For mild allergic reactions, over-the-counter antihistamines like Benadryl (diphenhydramine) 25-50mg every 4-6 hours or Zyrtec (cetirizine) 10mg once daily may be used to reduce symptoms such as itching, hives, and mild swelling.
• For severe allergic reactions (anaphylaxis), use an epinephrine auto-injector (EpiPen or Auvi-Q) immediately into the outer thigh through clothing, then call 911.
• After using epinephrine, lie down with legs elevated and wait for emergency services.
• People with known severe allergies should carry epinephrine auto-injectors at all times and wear medical alert identification.

Additional Measures

• Supplemental oxygen therapy should be administered initially to all patients experiencing anaphylaxis, especially those with evidence of hypoxia or respiratory distress 1.
• Education on avoidance of the allergen and follow-up with a primary care physician or allergist is crucial for patients with a history of anaphylaxis 1.

From the FDA Drug Label

Adrenalin® is a non-selective alpha and beta adrenergic agonist indicated for: Emergency treatment of allergic reactions (Type 1), including anaphylaxis Adults and Children 30 kg (66 lbs) or more: 0.3 to 0.5 mg (0.3 to 0.5 mL) intramuscularly or subcutaneously into anterolateral aspect of the thigh every 5 to 10 minutes as necessary Children 30 kg (66 lbs) or less: 0.01 mg/kg (0.01 mL/kg), up to 0.3 mg (0.3 mL), intramuscularly or subcutaneously into anterolateral aspect of the thigh every 5 to 10 minutes as necessary

The treatment for allergic reactions is epinephrine (IM). The dosage is as follows:

• Adults and children over 30 kg: 0.3 to 0.5 mg every 5 to 10 minutes as necessary
• Children under 30 kg: 0.01 mg/kg, up to 0.3 mg, every 5 to 10 minutes as necessary 2

From the Research

Allergic Reaction Treatment

• The treatment of allergic reactions should be guided by the severity of the reaction 3
• For severe allergic reactions, an intramuscular epinephrine injection into the lateral thigh should be given if cutaneous, mucosal and cardiovascular/respiratory symptoms occur 3, 4, 5
• Additionally, the patient should receive intravenous antihistamines and corticosteroids 3, 4, 5
• Epinephrine is the first-line treatment for anaphylaxis, and delayed epinephrine administration is a risk factor for fatal anaphylaxis 6
• Antihistamines may be beneficial in the treatment of anaphylaxis, but the role of corticosteroids is less clear 6, 4, 5

Treatment Modalities

• Epinephrine autoinjectors can be used by the patient themselves 4
• Histamine H(1)-antagonists are valuable in mild anaphylactic reactions, and should be given intravenously if possible 4
• Replacement of volume is crucial in antianaphylactic treatment, and crystalloids or colloid volume substitutes can be used 4
• Patients suffering from an anaphylactic episode should be observed over a period of 4-10 hours according to the severity of the symptomatology 4, 5

Patient Management

• Patients who have survived an anaphylactic reaction have to be thoroughly examined and an allergy diagnosis has to be performed with regard to the eliciting agent and the pathogenic mechanism involved 4
• Patients should be trained with regard to the nature of anaphylaxis, the major eliciting agents and the principles of behavior and coping with the situation, including the handling of epinephrine autoinjectors and the application of antianaphylactic medication 4, 5
• Educational programs for anaphylaxis have been developed to help patients manage their condition 4