What is the management plan for a patient with a history of anaphylaxis to hazelnut and mild allergy to tree nuts, presenting with facial edema and dyspnea of unknown origin?

Management of Allergic Reaction of Unknown Origin with History of Hazelnut Allergy

For a patient with facial edema and dyspnea of unknown origin who has a history of similar allergic reaction to hazelnut and mild tree nut allergy, immediate administration of epinephrine is the first-line treatment, followed by comprehensive evaluation by an allergist-immunologist to identify the trigger and prevent future episodes. 1

Immediate Management

• Administer epinephrine immediately as the drug of choice for anaphylaxis. If there is any doubt about whether symptoms represent anaphylaxis, it is better to administer epinephrine promptly 1
• For adults, use epinephrine autoinjector 0.3 mg IM in the anterolateral thigh 1
• Observe for at least 4-6 hours after treatment, as biphasic reactions can occur (reported in 1-20% of anaphylaxis cases) 1
• Provide supplemental oxygen and rapid volume expansion with crystalloids or colloids if the patient shows signs of cardiovascular compromise 1
• Consider adjunctive treatments such as H1-antihistamines, H2-antihistamines, and corticosteroids, though these should not replace or delay epinephrine administration 1

Discharge Plan

• Prescribe two doses of epinephrine autoinjector for the patient to carry at all times 1
• Provide proper instruction for self-administration of epinephrine 1
• Create an anaphylaxis emergency action plan 1
• Arrange for follow-up evaluation with an allergist-immunologist 1
• Advise patient to wear medical identification (e.g., Medic Alert jewelry) 1

Diagnostic Workup

• Refer to an allergist-immunologist for comprehensive evaluation to identify the trigger of the current reaction and assess cross-reactivity with other allergens 1
• Perform skin prick tests to evaluate potential allergens, including tree nuts and related foods 1, 2
• Consider component-resolved diagnosis to identify specific allergenic proteins, which can help assess risk for severe reactions 3
• For hazelnut allergy specifically, testing for sensitization to storage proteins (Cor a 9, Cor a 14) can help determine risk of severe reactions 2, 3
• Consider oral food challenges in a controlled medical setting with personnel experienced in treating anaphylaxis to confirm specific allergies 1

Special Considerations for Tree Nut Allergies

• Given the patient's history of hazelnut allergy and mild allergy to tree nuts, evaluate for cross-reactivity between different tree nuts 2, 4
• Be aware that patients with hazelnut allergy may have cross-reactivity with other tree nuts and even distantly related foods 5
• Tree nut allergies, including hazelnut, tend to persist throughout life with only a minority of cases improving during adolescence 3
• Peanuts and tree nuts cause the majority of fatalities from food-induced anaphylaxis 1

Long-term Management

• Complete avoidance of confirmed allergens is the safest approach for preventing future reactions 2
• Educate patient about reading food labels and avoiding cross-contamination, particularly when eating outside the home 2
• Consider referral for potential immunotherapy options in specialized centers, as oral immunotherapy (OIT) for tree nuts has shown effectiveness in conferring protection from accidental exposures 6
• For patients with multiple food allergies including tree nuts, omalizumab may be considered as an approved alternative management for reducing allergic reactions from accidental exposure 6

Important Caveats

• Delayed administration of epinephrine has been implicated in contributing to fatalities from anaphylaxis 1
• Many patients and caregivers fail to use epinephrine autoinjectors when anaphylaxis occurs, even for severe symptoms, due to various reasons including fear of needles or concerns about adverse effects 1
• Common adverse reactions to epinephrine include increased heart rate, palpitations, sweating, nausea, vomiting, difficulty breathing, dizziness, headache, and anxiety, but these symptoms usually subside rapidly 7
• Patients with a good response to initial treatment should be warned about the possibility of symptom recurrence (biphasic reaction) and instructed to seek proper medical attention if symptoms return 7