Anaphylaxis: skin or mucosal signs plus breathing trouble or low blood pressure — or two systems after exposure.
Before you read
Test yourself first: 3 questions
Question 1 of 3
A 16-year-old ate a cookie containing peanuts. Minutes later she has a tight throat, wheezing, vomiting and a pressure of 84/50, but no hives. She has a prescribed auto-injector. You should:
Answer: A. Skin signs are absent in a meaningful share of anaphylaxis, and a known allergen with airway, breathing and circulatory involvement is anaphylaxis regardless. Waiting for hives delays the one drug that reverses it — delay in epinephrine is the pattern seen in fatal reactions.
Question 2 of 3
A 72-year-old with coronary disease has hoarseness, wheezing, hives and a falling blood pressure after a wasp sting. He carries a prescribed epinephrine auto-injector. You should:
Answer: A. Anaphylaxis with airway and circulatory involvement kills quickly, and epinephrine is the only prehospital treatment that reverses it; there is no absolute contraindication when the reaction threatens life. Heart disease means you watch closely for chest pain, not that you withhold it.
Question 3 of 3
A 6-year-old is in anaphylaxis. Her own prescribed auto-injector is at home; her mother offers the adult auto-injector prescribed to herself. The appropriate course is to:
Answer: A. Auto-injectors come in strengths matched to body size, and EMTs assist only with the patient's own prescription. Support airway and breathing, transport and get advanced care that can give epinephrine — waiting on scene for her device loses time. Unless your EMS system carries its own epinephrine, the mother's device is someone else's drug at the wrong strength.
Keep the streak going with more questions like these, each with a full rationale.
Key points to remember
- Anaphylaxis: skin or mucosal signs plus breathing trouble or low blood pressure — or two systems after exposure.
- Hives are not required — up to one in five cases has no skin signs.
- Epinephrine by auto-injector into the lateral thigh is first-line; antihistamines do not reverse airway swelling or shock.
- Lay the patient flat with legs raised if hypotensive; let a breathing-distressed patient sit up.
- Symptoms can return hours later (biphasic reaction), so every patient given epinephrine needs evaluation.
Field priorities
- Give epinephrine early for anaphylaxis; a repeat dose may be needed if symptoms persist.
- Remove the trigger if possible (stinger scraped away, infusion stopped).
- Watch for sudden collapse when a hypotensive patient stands or sits up.
Coaching the patient
- Hives alone with normal breathing and blood pressure is a mild allergic reaction, not anaphylaxis — monitor closely, because it can progress.
Red flags: act now
- Hoarseness, stridor or throat tightness
- Swelling of the tongue or lips
- Hypotension or fainting after exposure
Allergic Reactions & Anaphylaxis: FAQs
What are the priority actions for Allergic Reactions & Anaphylaxis in the field?
Give epinephrine early for anaphylaxis; a repeat dose may be needed if symptoms persist. Remove the trigger if possible (stinger scraped away, infusion stopped). Watch for sudden collapse when a hypotensive patient stands or sits up.
What findings in Allergic Reactions & Anaphylaxis change your plan or your transport decision?
Hoarseness, stridor or throat tightness. Swelling of the tongue or lips. Hypotension or fainting after exposure.
What do I need to know about Allergic Reactions & Anaphylaxis for the NREMT?
Anaphylaxis: skin or mucosal signs plus breathing trouble or low blood pressure — or two systems after exposure. Hives are not required — up to one in five cases has no skin signs. Epinephrine by auto-injector into the lateral thigh is first-line; antihistamines do not reverse airway swelling or shock. Lay the patient flat with legs raised if hypotensive; let a breathing-distressed patient sit up.
What should the crew communicate or document for Allergic Reactions & Anaphylaxis?
Hives alone with normal breathing and blood pressure is a mild allergic reaction, not anaphylaxis — monitor closely, because it can progress.
