🩺 FCPS Paediatrics TOACS · Honeybee Sting Emergency
🐝 Insect Allergy (Nelson Chapter 187) · Anaphylaxis recognition · Stinger removal · Epinephrine
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⚡ OBSERVED/INTERACTIVE STATION · CPSP FORMAT · 7 MINUTES · HONEYBEE STING + VISIBLE STINGER
📋 Observed Station – “A child is stung by a honeybee and the stinger is visible”
👧🏼 Clinical Scenario (TOACS – read out / display):
A 6-year-old boy was playing in the garden when he suddenly cried out after being stung by a honeybee on his left forearm. The mother brought him to the emergency department within 10 minutes. On examination, the child is anxious, crying, and scratching his arm. A visible embedded stinger with attached venom sac is seen at the sting site, surrounded by a small wheal and flare. Within minutes, the child develops generalized urticaria, angioedema of the lips, coughing, and wheezing. Heart rate 140/min, respiratory rate 32/min, SpO₂ 91% on room air. No hypotension yet.
Task (observed): Demonstrate the immediate management: remove the stinger appropriately, assess for anaphylaxis, administer first-line treatment, and counsel the parent. The examiner will observe your technique and ask questions.
A 6-year-old boy was playing in the garden when he suddenly cried out after being stung by a honeybee on his left forearm. The mother brought him to the emergency department within 10 minutes. On examination, the child is anxious, crying, and scratching his arm. A visible embedded stinger with attached venom sac is seen at the sting site, surrounded by a small wheal and flare. Within minutes, the child develops generalized urticaria, angioedema of the lips, coughing, and wheezing. Heart rate 140/min, respiratory rate 32/min, SpO₂ 91% on room air. No hypotension yet.
Task (observed): Demonstrate the immediate management: remove the stinger appropriately, assess for anaphylaxis, administer first-line treatment, and counsel the parent. The examiner will observe your technique and ask questions.
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🔍 Clinical correlation: Embedded honeybee stinger with pulsating venom sac. Prompt removal (scraping, not tweezers) prevents further venom injection.
🚨 ANaphylaxis Alert: Systemic symptoms (wheezing, urticaria, angioedema) after Hymenoptera sting = anaphylaxis. First-line: intramuscular epinephrine 0.01 mg/kg (max 0.3 mg) in lateral thigh.
💡 Examiner instruction (interactive): Candidate must verbalize stinger removal method (scrape with fingernail or card, avoid squeezing venom sac). Demonstrate appropriate epinephrine autoinjector technique (or simulated). Answer questions about insect allergy natural history, VIT (venom immunotherapy), and prevention.
🗨️ Examiner Q&A · Allergy & Anaphylaxis Management
❓ Q1 (Examiner): “How would you remove the visible honeybee stinger? Why is method important?”
✅ Candidate answer: Remove by scraping horizontally with a fingernail, credit card edge, or scalpel blade. Avoid tweezers or squeezing because that may inject more venom from the attached venom sac. Rapid removal (within seconds) reduces venom dose and severity of reaction.
❓ Q2 (Examiner): “This child has generalized urticaria, wheezing, lip swelling. What is the first drug and dose?”
✅ Epinephrine IM (1:1000, 0.01 mg/kg, maximum single dose 0.3 mg for child, 0.5 mg adolescent). Given in lateral thigh (vastus lateralis). May repeat every 5-15 minutes if no improvement. Epinephrine is life-saving, no contraindication in anaphylaxis.
❓ Q3 (Examiner): “What is the differential diagnosis of this acute reaction (beyond anaphylaxis)?”
✅ vasovagal syncope (bradycardia, pallor without urticaria/wheeze), hereditary angioedema (no urticaria, no itch), panic attack, or severe asthma exacerbation. But with clear insect sting + immediate IgE-mediated signs → anaphylaxis most likely.
❓ Q4 (Examiner): “Which diagnostic tests confirm insect venom allergy after stabilization?”
✅ Skin prick test or intradermal test with Hymenoptera venoms (honeybee, yellow jacket, wasp, hornet). Alternatively serum specific IgE (venom sIgE). Testing should be done after 4-6 weeks (to avoid refractory period). Also baseline serum tryptase to rule out mastocytosis.
❓ Q5 (Examiner): “What is the natural history of insect sting anaphylaxis in children compared to adults?”
✅ Children with only cutaneous systemic reactions (urticaria, angioedema) have a very low risk (<10%) of developing severe anaphylaxis on subsequent stings. But those with respiratory or cardiovascular symptoms have ~40% risk of recurrence. Venom immunotherapy (VIT) is strongly indicated for moderate-to-severe reactions.
❓ Q6 (Examiner): “Indications for venom immunotherapy (VIT) in this child?”
✅ VIT recommended for children with systemic reactions beyond skin (respiratory, hypotension, airway edema). Also for those with mastocytosis, elevated baseline tryptase, or history of life-threatening anaphylaxis. VIT reduces risk from ~40% to <5% and provides long-term protection.
❓ Q7 (Examiner): “What additional medications are used as adjuncts in acute anaphylaxis?”
✅ Oxygen, IV fluids (bolus 20 mL/kg) for hypotension, inhaled albuterol for bronchospasm, H1 antihistamines (diphenhydramine/cetirizine), H2 blockers (ranitidine), and systemic corticosteroids (to prevent biphasic reaction). But epinephrine is the only life-saving drug.
❓ Q8 (Examiner): “How do you prevent future stings and anaphylaxis in this child?”
✅ Avoidance: no barefoot walking, avoid sweet drinks/foods outdoors, wear light-colored clothing, avoid perfumes. Prescribe epinephrine autoinjector (e.g., EpiPen Jr 0.15 mg or 0.3 mg based on weight), written emergency action plan, medical alert bracelet. Educate school and caregivers.
❓ Q9 (Examiner): “How long should the child be observed after an anaphylactic episode?”
✅ At least 4–6 hours due to risk of biphasic anaphylaxis (recurrence after initial resolution, up to 72h). If severe reaction or required multiple epinephrine doses, consider admission for 12–24h monitoring.
❓ Q10 (Examiner): “What is the role of epinephrine autoinjectors in children <15 kg?”
✅ For infants/children 7.5–15 kg, 0.1 mg autoinjector (e.g., Epinephrine Auto-Injector 0.1 mg). For 15–25 kg → 0.15 mg, >25 kg → 0.3 mg. Off-label weight-based dosing (0.01 mg/kg) may be given if autoinjector not available.
❓ Q11 (Examiner): “What are poor prognostic factors in insect sting anaphylaxis?”
✅ Older age, delayed epinephrine use, underlying asthma (especially poorly controlled), cardiovascular disease, mastocytosis, honeybee venom (higher risk of severe reactions vs vespid), and absence of venom immunotherapy.
❓ Q12 (Examiner): “What is the recurrence rate of sting anaphylaxis in children who receive VIT for 3-5 years?”
✅ After 3–5 years of VIT, >80-90% tolerate subsequent stings without systemic reaction. Even after stopping VIT, long-term protection persists in most children. For honeybee allergy, slightly higher relapse rate than vespid.
🗣️ Examiner probing points (extra): “What is the difference between honeybee vs yellow jacket venom?” → Honeybee venom has higher molecular weight allergens (phospholipase A2), barbed stinger remains; yellow jackets can sting repeatedly. “Can you give oral antihistamines alone?” → No, epinephrine is mandatory for anaphylaxis; antihistamines do not reverse hypotension or bronchospasm.
📘 Nelson Chapter 187 · Insect Allergy – Key Points
🐝 Hymenoptera families
Apids (honeybee, bumblebee) – barbed stinger, leaves venom sac. Vespidae (yellow jacket, wasp, hornet) – smooth stinger, multiple stings. Formicidae (fire ants).
Apids (honeybee, bumblebee) – barbed stinger, leaves venom sac. Vespidae (yellow jacket, wasp, hornet) – smooth stinger, multiple stings. Formicidae (fire ants).
⚡ Anaphylaxis risk
Children with isolated cutaneous reactions (urticaria only) → ~10% risk systemic with next sting. Respiratory/cardiovascular → ~40% recurrence. VIT indicated for moderate-severe.
Children with isolated cutaneous reactions (urticaria only) → ~10% risk systemic with next sting. Respiratory/cardiovascular → ~40% recurrence. VIT indicated for moderate-severe.
🩹 Stinger removal
Scrape, never pinch. Venom sac continues to inject venom for up to 1 min. Rapid removal reduces severity.
Scrape, never pinch. Venom sac continues to inject venom for up to 1 min. Rapid removal reduces severity.
💉 Epinephrine
IM thigh, 0.01 mg/kg (max 0.3 mg). First-line, no absolute contraindication. Auto-injector for out-of-hospital.
IM thigh, 0.01 mg/kg (max 0.3 mg). First-line, no absolute contraindication. Auto-injector for out-of-hospital.
🧪 Diagnosis
Skin test (prick/intradermal) or serum specific IgE to venom. Tryptase baseline for mast cell disorders. Testing >4 weeks after reaction.
Skin test (prick/intradermal) or serum specific IgE to venom. Tryptase baseline for mast cell disorders. Testing >4 weeks after reaction.
🛡️ Venom immunotherapy (VIT)
Highly effective (80-95% protection). Duration 3-5 years. Reduces risk of anaphylaxis, improves quality of life.
Highly effective (80-95% protection). Duration 3-5 years. Reduces risk of anaphylaxis, improves quality of life.
🏥 Biphasic anaphylaxis
Observe 4-6 hours after resolution. Risk factors: severe initial presentation, delayed epinephrine, large venom dose.
Observe 4-6 hours after resolution. Risk factors: severe initial presentation, delayed epinephrine, large venom dose.
⚠️ Prevention
Avoidance measures + epinephrine autoinjector + action plan + medical ID. School/childcare emergency plan mandatory.
Avoidance measures + epinephrine autoinjector + action plan + medical ID. School/childcare emergency plan mandatory.
⭐ High-yield for TOACS (Insulin/Insect):
✔ Visible stinger → demonstrate scraping removal.
✔ Anaphylaxis criteria (wheezing, urticaria, angioedema) → IM epinephrine.
✔ After stabilization → refer for allergy testing + VIT evaluation.
✔ Counseling: future stings can be fatal, always carry epinephrine autoinjector.
✔ Visible stinger → demonstrate scraping removal.
✔ Anaphylaxis criteria (wheezing, urticaria, angioedema) → IM epinephrine.
✔ After stabilization → refer for allergy testing + VIT evaluation.
✔ Counseling: future stings can be fatal, always carry epinephrine autoinjector.
🎭 Observed Station – Performance Checklist & Communication
🩺 Candidate Tasks (Role-play to Examiner):
1. Introduce yourself to mother, obtain consent.
2. Inspect sting site → identify embedded stinger with venom sac.
3. Remove stinger by scraping (using dorsal blade of scalpel or fingernail – verbalize “I will scrape horizontally to avoid squeezing venom”).
4. Rapid primary survey: Airway (stridor? hoarseness), Breathing (wheeze, SaO₂), Circulation (pulse, BP), Exposure (urticaria, angioedema).
5. Diagnose anaphylaxis → call for help, prepare epinephrine.
6. Administer epinephrine IM (simulate lateral thigh injection).
7. Start oxygen, place supine with legs elevated if hypotensive.
8. Reassess after 5 minutes, consider second dose.
9. Discuss need for transport/observation, antihistamines, steroids, and referral to allergist.
10. Counsel mother: “Your child had a severe allergic reaction; always carry epinephrine autoinjector and avoid bee exposure.”
1. Introduce yourself to mother, obtain consent.
2. Inspect sting site → identify embedded stinger with venom sac.
3. Remove stinger by scraping (using dorsal blade of scalpel or fingernail – verbalize “I will scrape horizontally to avoid squeezing venom”).
4. Rapid primary survey: Airway (stridor? hoarseness), Breathing (wheeze, SaO₂), Circulation (pulse, BP), Exposure (urticaria, angioedema).
5. Diagnose anaphylaxis → call for help, prepare epinephrine.
6. Administer epinephrine IM (simulate lateral thigh injection).
7. Start oxygen, place supine with legs elevated if hypotensive.
8. Reassess after 5 minutes, consider second dose.
9. Discuss need for transport/observation, antihistamines, steroids, and referral to allergist.
10. Counsel mother: “Your child had a severe allergic reaction; always carry epinephrine autoinjector and avoid bee exposure.”
📝 Examiner Marking Grid (Honeybee sting anaphylaxis):
- ✅ Correct stinger removal (scraping, no tweezers)
- ✅ Immediate recognition of anaphylaxis (urticaria + wheeze/angioedema)
- ✅ Epinephrine IM dose & site (0.01 mg/kg, lateral thigh)
- ✅ Appropriate use of autoinjector technique (if simulated)
- ✅ Adjunct therapy: O2, IV fluids, albuterol if bronchospasm persists
- ✅ Disposition: observation for biphasic reaction, allergy referral
- ✅ Parental counseling: avoidance, autoinjector prescription, medical ID, VIT discussion
- ✅ Knowledge of natural history (higher risk for honeybee vs vespid, VIT indications)
💬 Examiner feedback cues: “Why can’t you use tweezers?” (pumps venom). “How long will the child remain in ER?” (minimum 4-6h). “What if no improvement after epinephrine?” → repeat dose every 5-15 min, IV epinephrine in refractory shock. “Which children qualify for VIT?” → any with respiratory or CV symptoms, also those with mastocytosis or elevated tryptase.
📚 Key reference (Nelson’s Pediatrics 22e, Chapter 187 – Insect Allergy):
– Systemic reactions to Hymenoptera stings occur in 0.4-0.8% of children.
– For children with only cutaneous systemic reactions, VIT is usually not required; but with respiratory symptoms, VIT reduces future anaphylaxis risk from 40% to <5%.
– Emergency epinephrine autoinjector should be prescribed for any child with moderate/severe reaction.
– Systemic reactions to Hymenoptera stings occur in 0.4-0.8% of children.
– For children with only cutaneous systemic reactions, VIT is usually not required; but with respiratory symptoms, VIT reduces future anaphylaxis risk from 40% to <5%.
– Emergency epinephrine autoinjector should be prescribed for any child with moderate/severe reaction.