1
Scene Size-Up & BSI ▼
- Gloves, eye protection — BSI before contact
- Scene safety — bees/wasps still present? Food allergen in environment?
- Determine # patients, mechanism (food, medication, sting, unknown)
- Request ALS early — anaphylaxis can deteriorate rapidly
- Note any epi-pen or medications at scene
↓
2
Initial Assessment — ABCs
- Airway: Stridor, hoarseness, throat tightness, swelling of lips/tongue/uvula?
- Breathing: Wheezing, work of breathing, SpO2 — respiratory failure can develop fast
- Circulation: Radial pulse, BP, skin signs — hypotension = distributive shock
- Skin: Urticaria (hives), flushing, pruritus, angioedema — present in ~90% of anaphylaxis
- Neuro: Anxiety, altered mentation, syncope, sense of impending doom
↓
Anaphylaxis Criteria Met?
Allergen exposure + multi-system involvement OR BP drop
Allergen exposure + multi-system involvement OR BP drop
YES — Anaphylaxis
Epinephrine IM immediately — do not delay for IV access or history
NO — Allergic Rxn
Monitor closely, prepare epi, full assessment below — can progress to anaphylaxis
⚠ Recognition Criteria
Dx
Anaphylaxis is Likely if ANY of the Following:
- Criterion 1: Acute onset + skin/mucosal changes (hives, flushing, swelling) + EITHER respiratory compromise OR BP drop / collapse
- Criterion 2: Rapid onset of 2+ organ systems after likely allergen: skin, respiratory, cardiovascular, GI
- Criterion 3: BP drop after known allergen exposure — even without skin signs
⚠ Absence of skin findings does NOT rule out anaphylaxis — up to 10% present without hives or flushing. If in doubt, treat.
↓
3
SAMPLE History ▼
- Signs & Symptoms — onset time, progression, systems affected
- Allergies — known allergens, prior reactions, severity of past reactions
- Medications — epi-pen prescribed? Beta-blockers? ACE inhibitors? (both complicate treatment)
- Pertinent hx — prior anaphylaxis, asthma, mastocytosis (higher risk of severe reaction)
- Last oral intake — what and when; foods, medications, supplements
- Events — what was the exposure? When? How much? Sting site? New medication?
⚠ Beta-blockers blunt response to epinephrine and can cause refractory anaphylaxis. Flag for ALS — glucagon may be needed.
↓
📊 Symptom Classification
① Select All Systems Involved
Tap every system showing symptoms:
Allergic Reaction — Monitor Closely
Skin involvement only. Not yet anaphylaxis — but can progress rapidly. Keep epi ready. Reassess every 2–3 minutes. Any progression to a second system = anaphylaxis, give epi.
⚡ Anaphylaxis — Epinephrine Now
Multi-system involvement confirmed. Do not wait — administer epinephrine IM immediately. Position patient, O2 15L NRB, ALS intercept.
🚨 Critical Anaphylaxis — Airway / Vascular Collapse
Airway compromise, hemodynamic collapse, or altered LOC. Epinephrine IM NOW. ALS immediately. Prepare BVM. Load and go.
↓
5
💉 Epinephrine — First-Line Treatment
💉 Epinephrine 1:1,000 IM
Adult (> 30 kg)
0.3 mg
Auto-injector (EpiPen)
Pediatric (< 30 kg)
0.15 mg
EpiPen Jr / auto-injector
Site: Anterolateral mid-thigh — can administer through clothing
Do NOT use: Deltoid, buttocks (unpredictable gluteal absorption)
Hold: 10 seconds after injection to ensure full dose delivery
Do NOT use: Deltoid, buttocks (unpredictable gluteal absorption)
Hold: 10 seconds after injection to ensure full dose delivery
↺ Repeat dose in 5–15 minutes if no improvement or symptoms return. A second dose is safe and appropriate.
Epi is the ONLY first-line treatment. Antihistamines (diphenhydramine) and steroids are secondary — they do not reverse airway compromise or vascular collapse and should never delay epinephrine.
↓
6
Positioning & Airway
Hypotension / Shock
Supine + Legs Elevated
No respiratory distress • BP drop • Syncope
Respiratory Distress
Semi-Recumbent / Upright
Wheezing • Stridor • SOB • Sat low
Do NOT allow patient to stand or sit upright if hypotensive. Fatal positional cardiac arrest has been documented — keep supine until hemodynamically stable.
BLS O₂ 15L via NRB mask — all anaphylaxis patients regardless of SpO2
BLS Suction if vomiting — high aspiration risk with altered LOC
BLS BVM ready — upper airway edema can progress to complete obstruction
BLS Continuous reassessment q2 min — response to epi typically within 5–10 minutes
↓
7
Secondary Interventions
ALS Diphenhydramine 25–50 mg IV/IM — antihistamine; secondary only, does not reverse anaphylaxis
ALS Albuterol 2.5 mg nebulized — for bronchospasm component not resolved by epi
ALS Normal Saline 1–2L IV bolus — for persistent hypotension after epi
ALS Glucagon 1–2 mg IV/IM — for patients on beta-blockers refractory to epinephrine
ALS IV Epinephrine — only if IM epi and fluids fail; requires ALS administration
↓
⚠ Biphasic Anaphylaxis Warning
Symptoms can return 1–8 hours after initial resolution — even without re-exposure to the allergen. All anaphylaxis patients require hospital evaluation and observation regardless of apparent recovery in the field. Document symptom resolution time and inform receiving facility.
↓
8
Transport & ALS Intercept
All anaphylaxis patients transport to ED — even if fully resolved after epi. Biphasic reaction risk requires minimum 4–6 hour observation.
Pre-notify receiving facility — epi given, dose, time, current status, ALS en route or needed
Document: allergen exposure, onset time, epi dose + time given, response to treatment, repeat dose if given
🚨 ALS Intercept Indicated
- Airway compromise — stridor, hoarseness, poor air movement
- Persistent hypotension after epinephrine
- Altered mental status / loss of consciousness
- Patient on beta-blockers (refractory to epi — needs glucagon)
- Second epi dose required
- SpO2 not improving with O2 and epi
- Pediatric anaphylaxis — strongly consider ALS for all
📋 Common Triggers Reference
| Category | Common Triggers |
|---|---|
| Food | Peanuts, tree nuts, shellfish, fish, milk, eggs, wheat, soy, sesame |
| Medications | Penicillin / beta-lactam antibiotics, NSAIDs, aspirin, contrast dye, chemotherapy agents |
| Insect Venom | Honeybees, yellow jackets, hornets, wasps, fire ants |
| Latex | Gloves, balloons, medical equipment — cross-reactive with banana, avocado, kiwi |
| Exercise-Induced | Rare — often requires cofactor (food + exercise). Can occur without allergen. |
| Idiopathic | 15–20% of cases — no identifiable trigger found. Prior episodes increase risk. |