🔎 Recognise it fast

• Sudden onset airway/breathing/circulation compromise ± skin/mucosal changes (urticaria, flushing, angioedema).
• Life-threatening features: hoarse voice/stridor, wheeze or ↑ work of breathing, SpO₂ <94%, hypotension/shock, confusion/collapse.
• ⚠️ Rash alone isn’t anaphylaxis—but don’t be reassured by its absence.

📞 Call for help

• Hospital: Resus/MET/2222. Community: 🚑 999.

🩺 First steps (do in parallel)

• Remove the trigger if possible: stop infusion, remove stinger, stop ingestion.
• Position: lie flat + elevate legs. If pregnant (>20 weeks) lie on left side. Sitting may help breathing but avoid standing or sudden sitting upright (can precipitate collapse).

💉 IM Adrenaline (1:1000) — lateral thigh

• 👨 Adult & child >12 y: 0.5 mg (0.5 mL)
• 👧 Child 6–12 y: 0.3 mg (0.3 mL)
• 👶 Child 6 mo–6 y: 0.15 mg (0.15 mL)
• 👼 Infant <6 mo: 100–150 micrograms (0.1–0.15 mL)
• ⏱ Repeat IM adrenaline every 5 minutes if no improvement.

💨 Oxygen + airway

• 💨 High-flow O₂ 15 L/min via non-rebreather.
• Airway threatened? early senior/anaesthetics involvement; prepare for rapid deterioration.
• Stridor: consider nebulised adrenaline as a bridge while securing airway help.

💧 Circulation

• 💧 IV fluids: Adult 500–1000 mL 0.9% NaCl (or balanced crystalloid) bolus; repeat as needed. Child 20 mL/kg.
• Expect large volumes in severe cases (vasodilation + capillary leak).

🌬 Bronchospasm

• Wheeze: nebulised salbutamol 5 mg; add ipratropium if severe.

🧪 Confirmatory samples (after treating)

• 🧪 Mast cell tryptase: take as soon as feasible (ideally within 1–2 h), then a baseline later (often at ~24 h or at follow-up).
• More often elevated with drug/sting reactions than isolated food reactions.

💊 What’s NOT first-line

• ⚠️ Antihistamines and steroids are adjuncts (skin symptoms / late-phase) and must never delay adrenaline.

🔥 Refractory anaphylaxis (persistent ABC problems despite 2 IM doses + fluids)

• 🚰 Continue rapid fluid resuscitation (adults may need 3–5 L).
• 💉 Escalate to adrenaline infusion with senior support + continuous monitoring.
• Second vasopressor may be needed (e.g. noradrenaline/vasopressin/metaraminol) if shock persists.
• 📌 If on beta-blockers and adrenaline response is poor → consider IV glucagon.
• 💔 Cardiac arrest: follow ALS; IV/IO adrenaline per algorithm; consider E-CPR/ECMO where available.

✅ Key message: Treat immediately if there are any life-threatening ABC signs. 👉 IM adrenaline is safe, fast, and the intervention most linked to survival.

💉 IV Adrenaline infusion (refractory anaphylaxis — practical set-up)

• When? Persistent respiratory and/or cardiovascular compromise despite two appropriate IM adrenaline doses + ongoing resuscitation (especially hypotension/hypoxia). Seek senior/critical care help early.
• While setting up: continue IM adrenaline every 5 minutes until the infusion is running.

• Preparation (peripheral low-dose infusion):
  • Mix 1 mg adrenaline = 1 mL of 1 mg/mL (1:1000) into 100 mL of 0.9% sodium chloride (final concentration 10 micrograms/mL).
  • Prime and connect via an infusion pump using a dedicated line.
  • DO NOT “piggy-back” onto another infusion line (unless using an anti-reflux valve).
  • DO NOT infuse on the same side as a BP cuff (BP cycling can interrupt flow and increases extravasation risk).
  • Check the cannula site frequently for patency/extravasation.
• Starting rate (children & adults):
  • 0.5–1.0 mL/kg/hour depending on severity.
  • Guide:
    • Moderate (still compromised but not profoundly shocked): 0.5 mL/kg/h (~0.1 micrograms/kg/min).
    • Severe (hypotensive and/or markedly hypoxic): 1.0 mL/kg/h.
  • Titrate up/down to clinical response, aiming for the lowest effective rate.
  • After any rate change, allow 5–10 minutes to see the new steady response.
• Mandatory monitoring:
  • Continuous ECG, pulse oximetry, and non-invasive BP at least every 5 minutes (plus HR, RR, mental state).
  • Watch for arrhythmia, myocardial ischaemia symptoms, and ongoing hypoperfusion.
• Adverse effects / “too much adrenaline” clues:
  • Hypertension is a key red flag for overdose (especially if the patient is no longer shocked).
  • Tachycardia, tremor, pallor with a normal or raised BP may indicate excess.
  • If side effects occur: reduce the infusion rate (or stop if severe) and reassess ABC.
• If still shocked despite infusion + fluids:
  • Escalate early to critical care; you may need a second vasopressor per local shock protocol.
  • If on beta-blockers and response is poor → consider IV glucagon (per local guidance).
  • Prolonged infusions usually require central access (peripheral/IO is acceptable as a bridge).
• Weaning: Once stable (BP/oxygenation improving, minimal wheeze/stridor), down-titrate gradually to the lowest effective rate, then stop, with continued observation for recurrence.