What is the immediate treatment for an allergic reaction to nuts, specifically anaphylaxis?

Immediate Treatment for Nut-Induced Anaphylaxis

Administer intramuscular epinephrine immediately into the anterolateral thigh—this is the single most critical intervention that saves lives, and delayed administration is directly linked to fatal outcomes. 1, 2

First-Line Treatment: Epinephrine

Epinephrine is the only first-line treatment for anaphylaxis and must never be delayed. 1, 3

Dosing Protocol

• Weight 10-25 kg: 0.15 mg IM via autoinjector into anterolateral thigh 1, 4
• Weight >25 kg: 0.3 mg IM via autoinjector into anterolateral thigh 1, 4
• Alternative dosing: 0.01 mg/kg (maximum 0.5 mg) if using 1:1000 solution 1, 3
• Repeat doses: May be required every 5-15 minutes as needed 1
• Multiple doses needed: Approximately 19% of pediatric food-induced anaphylaxis cases require more than one dose of epinephrine 5

Critical Administration Details

• Site matters: Always inject into the anterolateral thigh, never into buttocks, digits, hands, or feet 3
• Route matters: Intramuscular administration is superior to subcutaneous for anaphylaxis 3, 6
• Timing is everything: Peanuts and tree nuts cause the majority of fatal food-induced anaphylaxis, and fatalities are specifically associated with delayed or improper epinephrine dosing 1, 2

Adjunctive Treatments (After Epinephrine)

These treatments occur concomitantly but should never replace or delay epinephrine administration: 1, 2

Immediate Adjuncts

• Albuterol (β2-agonist): MDI 4-8 puffs (child) or 8 puffs (adult), OR nebulized 1.5 mL (child) or 3 mL (adult) every 20 minutes or continuously 1
• Diphenhydramine (H1-antihistamine): 1-2 mg/kg per dose, maximum 50 mg IV or oral (oral liquid absorbs faster than tablets) 1
• Supplemental oxygen: Administer as needed 1
• IV fluids: Large volumes if patient has orthostasis, hypotension, or incomplete response to epinephrine 1
• Patient positioning: Recumbent with lower extremities elevated if tolerated 1

Hospital-Based Additional Adjuncts

• Ranitidine (H2-antihistamine): 1-2 mg/kg per dose, maximum 75-150 mg 1
• Corticosteroids: Prednisone 1 mg/kg (maximum 60-80 mg) or methylprednisolone 1
• Continuous epinephrine infusion: Consider for persistent hypotension with continuous monitoring 1

Observation Period

All patients who receive epinephrine must be transferred to an emergency facility for observation. 1

• Standard observation: 4-6 hours minimum for most patients 1, 4
• Extended observation or admission: Required for severe/refractory symptoms, history of biphasic reactions, coexisting severe asthma, cardiovascular disease, or delayed epinephrine administration 4, 6
• Biphasic reaction risk: Occurs in 1-20% of cases, typically around 8 hours but can occur up to 72 hours later 1, 4

Discharge Requirements

Every patient must leave with all five components: 1, 2, 4

1. Epinephrine Autoinjectors

• Prescribe two doses to carry at all times 2, 4
• Provide hands-on training in proper use before discharge 4
• Establish plan for monitoring expiration dates 1, 4

2. Written Emergency Action Plan

• Detail trigger avoidance strategies 2, 4
• Include early symptom recognition 1, 2
• Specify when and how to administer epinephrine 2

3. Medical Identification

• Medical identification jewelry or anaphylaxis wallet card 1, 4

4. Adjunctive Medications (2-3 day course)

• Diphenhydramine: Every 6 hours 1, 4
• Ranitidine: Twice daily 1, 4
• Prednisone: Daily 1, 4

Important caveat: Evidence supporting corticosteroids and antihistamines for preventing biphasic reactions is weak and contradictory, but they are still commonly prescribed 4

5. Follow-Up Arrangements

• Appointment with primary care provider 1, 4
• Referral to allergist/immunologist for comprehensive evaluation, skin prick testing, and long-term management 2, 4, 6

High-Risk Patient Identification

Patients at highest risk for fatal anaphylaxis include: 1

• Adolescents and young adults 1
• Those with previous anaphylaxis history 1
• Patients with asthma, especially poorly controlled 1, 5
• Known allergy to peanuts, tree nuts, fish, or shellfish 1

All high-risk patients should be prescribed epinephrine autoinjectors even before their first anaphylactic event. 1

Common Pitfalls to Avoid

• Never delay epinephrine while administering antihistamines or other adjunctive treatments—this delay kills patients 1, 2, 6
• Never discharge without observation—death can occur within 30 minutes to 2 hours of exposure 1, 6
• Never prescribe only one autoinjector—approximately 19% of reactions require multiple doses 4, 5
• Never assume mild symptoms will stay mild—progression to severe anaphylaxis can be rapid and unpredictable 1, 6
• Many patients fail to carry or use their autoinjectors despite training due to fear of needles or adverse effects—address these barriers explicitly during education 2, 7