What is the difference in management between anaphylaxis and oral allergy syndrome (OAS)?

From the Guidelines

The management of anaphylaxis and oral allergy syndrome (OAS) differs significantly in urgency, medications, and approach, with anaphylaxis requiring immediate emergency treatment with intramuscular epinephrine as the first-line therapy, whereas OAS management is typically conservative and non-urgent. The key difference in management between anaphylaxis and OAS lies in their underlying pathophysiology and the potential for anaphylaxis to be life-threatening. Anaphylaxis involves a systemic immune response that can affect multiple organ systems, whereas OAS is a localized allergic reaction confined to oral tissues due to cross-reactivity between certain pollens and raw fruits or vegetables 1.

Key Management Strategies

• Anaphylaxis requires immediate treatment with intramuscular epinephrine (0.3-0.5 mg for adults, 0.15-0.3 mg for children) as the first-line therapy, which may need to be repeated every 5-15 minutes if symptoms persist 1.
• Patients with anaphylaxis should be placed in a supine position with legs elevated, receive high-flow oxygen, and obtain IV access for fluid resuscitation with normal saline.
• Secondary medications for anaphylaxis include H1 antihistamines (diphenhydramine 25-50 mg IV/IM), H2 blockers (ranitidine 50 mg IV), and corticosteroids (methylprednisolone 125 mg IV).
• In contrast, OAS management is typically conservative and non-urgent, focusing on avoiding raw trigger foods or processing them (cooking, peeling, or microwaving) to denature the responsible proteins.
• Mild OAS symptoms often resolve spontaneously within minutes and can be managed with oral antihistamines like cetirizine 10 mg or diphenhydramine 25-50 mg if needed.

Importance of Prompt Treatment

Prompt recognition and treatment of anaphylaxis are crucial to prevent morbidity and mortality, as systemic allergic reactions can rapidly progress from mild to life-threatening symptoms 1.

Education and Training

Patients and caregivers need training in how to recognize anaphylaxis and use an epinephrine autoinjector (EA), and education about anaphylaxis is advised to ensure familiarity with the specific device prescribed 1.

From the Research

Difference in Management

The management of anaphylaxis and oral allergy syndrome (OAS) differs in several key aspects:

• Anaphylaxis is a life-threatening condition that requires immediate administration of epinephrine, typically via an auto-injector or intramuscular injection 2, 3
• OAS, on the other hand, is generally a milder condition that may not require epinephrine administration
• In anaphylaxis, antihistamines and corticosteroids may be used as secondary treatments, but should not delay the administration of epinephrine 2, 4
• The use of corticosteroids in anaphylaxis is still a topic of debate, with some studies suggesting they may reduce the length of hospital stay, but others finding no clear benefit 4

Treatment Approaches

Treatment approaches for anaphylaxis include:

• Immediate administration of epinephrine via an auto-injector or intramuscular injection 2, 3
• Use of antihistamines and corticosteroids as secondary treatments 2, 4
• Aggressive fluid resuscitation to treat intravascular volume depletion 2
• Supplemental oxygen and other supportive care as needed 2, 5
• In contrast, OAS may be managed with avoidance of trigger foods, antihistamines, and other symptomatic treatments

Key Considerations

Key considerations in the management of anaphylaxis include:

• Prompt recognition and treatment of symptoms 2, 6
• Use of epinephrine auto-injectors for self-administration 3, 5
• Individualized anaphylaxis action plans and specialist assessment 6
• Education and training for patients and healthcare providers on anaphylaxis recognition and treatment 5