12-phase flow (12)

1. 1FRAME
   Frame as a CHRONIC IgE-mediated reactivity managed through avoidance + emergency action plan + auto-injector, with optional disease-modifying immunomodulatory therapy (peanut OIT, omalizumab) per EAACI 2025. Acute reactions route to allergy.anaphylaxis.v1.
   advance: Chronic FA framing set; rescue route to anaphylaxis engine noted
2. 2ENTRY
   Recognise reproducible food-triggered reactions (urticaria/angioedema/wheeze/GI/anaphylaxis within minutes-2h) OR a positive food-sIgE / SPT in the context of a compatible history. Distinguish IgE-FA from non-IgE FA (FPIES, EoE, proctocolitis) and from oral allergy syndrome (PFAS).
   inputs: detailed_reaction_history
   actions: workup.anaphylaxis
   advance: Compatible history elicited; non-IgE patterns triaged
3. 3CONTEXT
   Establish atopic background (eczema, asthma, allergic rhinitis), cofactors (exercise, NSAIDs, alcohol — food-dependent exercise-induced anaphylaxis), epinephrine status, and any baseline tryptase. Identify the LEAP window in high-risk infants 4-11 mo (PMID 25705822).
   inputs: atopic_comorbidities, asthma_control_status, epinephrine_auto_injector_status
   advance: Atopic + cofactor + auto-injector context established; LEAP window flagged if applicable
4. 4INITIAL_WORKUP
   Targeted sIgE and/or SPT against the suspected food(s) (EAACI 2025 PMID 39473345). DO NOT order broad untargeted IgE panels — false positives are common and drive unnecessary avoidance. Component-resolved diagnostics (Ara h 2 for peanut, Cor a 14 for hazelnut, Bos d 8 for milk) refine sensitisation vs allergy and predict severity.
   inputs: food_specific_ige_panel
   actions: panel.cbc
   advance: Targeted sIgE / SPT result available; broad panels avoided
5. 5BRANCHING_WORKUP
   When history-sIgE concordance is incomplete, the GOLD-standard test is the medically-supervised oral food challenge (OFC) — done in an OIT-capable centre with rescue epinephrine ready. Baseline tryptase if severe/recurrent (mastocytosis/HAT screen). Alpha-gal IgE if delayed mammalian-meat reactions. Routes to allergy.mast-cell-activation-syndrome.core.v1 if tryptase elevated.
   inputs: baseline_tryptase_if_available
   actions: workup.anaphylaxis
   advance: OFC scheduled or completed where indicated; mast-cell/alpha-gal differentials addressed
6. 6DIFFERENTIAL
   Terminal differential: IgE-FA (this engine) vs non-IgE FA (FPIES, EoE, proctocolitis — different pathophysiology, no sIgE) vs oral allergy syndrome / pollen-food allergy syndrome (Bet v 1-related, raw fruit, mild oropharyngeal) vs scombroid (histamine in spoiled fish, not allergy) vs alpha-gal syndrome (delayed 3-6h post mammalian meat, tick-mediated) vs food intolerance (e.g., lactose, fructose — non-immune).
   advance: IgE-FA vs alternative diagnosis assigned
7. 7RISK_STRATIFICATION
   Severity tier driven by prior reaction grade (mild cutaneous vs systemic anaphylaxis), sIgE level + component (Ara h 2 highly predictive for peanut), asthma control (the single strongest modifier of fatal anaphylaxis), baseline tryptase, cofactor exposure, and access to emergency care. Stratifies the prescribing intensity of the action plan and the OIT-eligibility discussion.
   advance: Risk tier assigned (mild cutaneous / moderate systemic / high-risk anaphylaxis); OIT candidacy framed
8. 8TREATMENT
   EAACI 2025 (PMID 39473345) management has 4 pillars: (1) STRICT AVOIDANCE + dietitian-supported nutritional adequacy + label reading; (2) WRITTEN EMERGENCY ACTION PLAN + epinephrine auto-injector (two devices for at-risk; technique re-taught at every visit); (3) DISEASE-MODIFYING IMMUNOMODULATION — peanut OIT (Palforzia, ages 1-17, daily dose-escalation maintenance) RECOMMENDED for peanut, SUGGESTED for milk and egg (>=4 y); omalizumab SUGGESTED for IgE-FA from age 1 (OUtMATCH PMID 38407394); sublingual + epicutaneous immunotherapy SUGGESTED for peanut but not yet routinely available at point of care; (4) PSYCHO-SOCIAL SUPPORT — clinical-psych referral for significant anxiety/coping burden.
   inputs: epinephrine_auto_injector_status, age, asthma_control_status
   advance: Action plan + auto-injector prescribed; disease-modifying therapy discussed with shared decision-making
9. 9DISPOSITION
   Almost entirely outpatient/allergy-clinic. Inpatient/ED only when an acute reaction is in progress (route to allergy.anaphylaxis.v1). Centre-based supervised OFC and OIT initiation/uptitration sessions require an OIT-capable allergy facility with rescue epinephrine and a 1-2h post-dose observation window.
   inputs: access_to_emergency_care
   advance: Outpatient allergy follow-up arranged; OIT centre identified if therapy elected
10. 10MONITORING
    Auto-injector expiry + carry + technique at every visit. Dietitian re-review annually (especially milk/egg/wheat allergies for growth + nutrient adequacy). Annual sIgE / component testing for evidence of natural tolerance (especially milk/egg/wheat — frequent in childhood). OIT-on-treatment surveillance: daily dosing adherence, dose-reaction-and-cofactor diary, EoE symptom screen, asthma control. Omalizumab: q2-4wk SC; injection-site + rare anaphylaxis-to-omalizumab counselling.
    inputs: eosinophilic_gi_symptoms
    actions: workup.anaphylaxis
    advance: Annual sIgE / dietitian + auto-injector check completed; OIT/omalizumab surveillance per protocol
11. 11FOLLOWUP
    Lifelong chronic-allergy maintenance: written action plan + auto-injector + label-reading habit + school/workplace plan + medical-alert identification. School staff training in epinephrine administration. Re-evaluation for natural tolerance (milk/egg/wheat childhood allergies) via supervised OFC at allergist discretion. Lifelong avoidance counselling for peanut/tree-nut/sesame/shellfish (low natural-tolerance rate).
    inputs: atopic_comorbidities
    advance: Action plan reviewed; school/workplace plan in place; tolerance re-evaluation scheduled where indicated
12. 12RED_FLAGS
    Two-organ system involvement OR cardiovascular compromise OR airway compromise = anaphylaxis → route IMMEDIATELY to allergy.anaphylaxis.v1 for IM epinephrine + supportive care. New dysphagia / food impaction / persistent retrosternal pain during OIT = possible eosinophilic esophagitis (refer for endoscopy). New baseline tryptase >=11.4 ng/mL = mastocytosis/HAT workup.
    inputs: eosinophilic_gi_symptoms, baseline_tryptase_if_available
    actions: workup.anaphylaxis
    advance: Anaphylaxis routed out; OIT-EoE flagged; tryptase pathway triggered if elevated