What are the treatment options for an allergic reaction in an outpatient setting?

From the Guidelines

Outpatient treatment for allergic reactions should prioritize epinephrine administration as the first-line treatment, with 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 and highest quality study 1. The treatment approach for allergic reactions in an outpatient setting involves a combination of medications and patient education.

• First-line treatment: Epinephrine administered intramuscularly is the cornerstone of anaphylaxis management, and its underutilization is a concern 1.
• Adjunctive treatment: Antihistamines, such as diphenhydramine, and glucocorticoids may be used, although their role in anaphylaxis management is not clearly supported by evidence 1.
• Patient education: Patients with known severe allergies should carry an epinephrine auto-injector and use it immediately for symptoms like throat swelling, breathing difficulty, or lightheadedness, followed by emergency care 1.
• Follow-up care: Patients should be educated on avoidance of allergens, and consideration should be given to referral to an allergist for further management and potential immunotherapy 1. It is essential to note that the diagnosis and management of anaphylaxis must occur rapidly, and confirmatory testing for anaphylaxis has poor sensitivity 1.
• Risk factors for severe anaphylaxis include cardiovascular disease, asthma, older age, and additional coexisting, comorbid conditions 1.
• Identifying and avoiding triggers is crucial for preventing future reactions, and patients with significant allergies should consider allergy testing and possibly immunotherapy for long-term management 1.

From the FDA Drug Label

Emergency treatment of allergic reactions (Type I), including anaphylaxis, which may result from allergic reactions to insect stings, biting insects, foods, drugs, sera, diagnostic testing substances and other allergens, as well as idiopathic anaphylaxis or exercise-induced anaphylaxis. Control of severe or incapacitating allergic conditions intractable to adequate trials of conventional treatment: Seasonal or perennial allergic rhinitis Bronchial asthma Contact dermatitis Atopic dermatitis Serum sickness Drug hypersensitivity reactions

For outpatient treatment of an allergic reaction,

• Epinephrine (IM) 2 is used for emergency treatment of allergic reactions (Type I), including anaphylaxis.
• Prednisone (PO) 3 is used for control of severe or incapacitating allergic conditions. Key points:
• Epinephrine is used for emergency treatment.
• Prednisone is used for control of severe allergic conditions.

From the Research

Allergic Reaction Outpatient Treatment

• The management of allergic reactions and anaphylaxis in the emergency department involves the use of epinephrine, corticosteroids, and antihistamines 4.
• Corticosteroids are frequently used in the emergency treatment of anaphylaxis, with an average rate of use of 67.99% 5.
• The use of corticosteroids in anaphylaxis may reduce the length of hospital stay, but there is no consensus on whether they reduce biphasic anaphylactic reactions 5.
• Antihistamines and corticosteroids are used to prevent recurrence of anaphylaxis, but have a delayed onset compared to epinephrine 6.
• Epinephrine is the first-line treatment for anaphylaxis, and early administration is critical to prevent a potentially fatal outcome 7, 8.
• Prehospital treatment with epinephrine and antihistamines may reduce the likelihood of uncontrolled reactions and hospital admission 7.
• Corticosteroid use in anaphylaxis should be revisited, as it may be associated with an increased need for intravenous fluids and hospital admission 7.

Treatment Options

• Epinephrine: administered intramuscularly for rapid action, and can also be nebulized or given intravenously in severe cases 6, 7, 8.
• Antihistamines: used to prevent recurrence of anaphylaxis, but have a delayed onset compared to epinephrine 6, 7, 8.
• Corticosteroids: used to reduce the length of hospital stay and prevent biphasic anaphylactic reactions, but their use should be revisited 5, 7.

Key Considerations

• Early administration of epinephrine is critical to prevent a potentially fatal outcome 7, 8.
• Antihistamines and corticosteroids should be used in conjunction with epinephrine, but not as a replacement for it 7, 8.
• Patient education and allergy identification are important aspects of post-crisis management 6.