Anaphylaxis is a severe, fast-moving allergic reaction that can affect breathing, blood pressure, skin, and digestion at the same time. It can be triggered by foods, insect stings, medicines, latex, or other allergens. Acting quickly matters because symptoms can worsen within minutes and can become life-threatening.
An epinephrine auto-injector, often called an EpiPen, is designed to deliver emergency medicine before professional help arrives.
Key Facts
- Anaphylaxis is a medical emergency and should be treated quickly with epinephrine when severe allergy symptoms appear.
- Common signs include trouble breathing, throat tightness, swelling of the lips or tongue, widespread hives, vomiting, dizziness, or fainting.
- Use the auto-injector on the outer middle thigh, through clothing if needed, following the device instructions.
- Call emergency services immediately after using epinephrine because symptoms can return or continue after the first dose.
- A second auto-injector may be needed if symptoms do not improve or return before emergency help arrives, following a prescribed action plan.
- Time matters: reaction time = time symptoms begin to time epinephrine is given, and shorter reaction time improves emergency response.
Vocabulary
- Anaphylaxis
- A severe allergic reaction that can affect multiple body systems and may become life-threatening very quickly.
- Epinephrine
- An emergency medicine that helps open airways, raise blood pressure, and reduce dangerous allergic reaction effects.
- Auto-injector
- A spring-loaded device that delivers a measured dose of medicine when pressed firmly against the body.
- Allergen
- A substance that can trigger an allergic reaction in a sensitive person.
- Biphasic reaction
- A return of anaphylaxis symptoms after they first improve, which is one reason emergency medical care is still needed.
Common Mistakes to Avoid
- Waiting to see if symptoms get worse: this is wrong because anaphylaxis can progress rapidly, and delayed epinephrine increases danger.
- Using an inhaler or antihistamine instead of epinephrine for severe symptoms: this is wrong because those medicines do not reliably treat airway swelling or low blood pressure.
- Injecting into the hand, arm, or buttock: this is wrong because auto-injectors are intended for the outer middle thigh for fastest and safest emergency delivery.
- Leaving the person alone after giving epinephrine: this is wrong because symptoms can return, breathing can worsen, and emergency responders need accurate information.
Practice Questions
- 1 A student eats a snack at 12:10 and develops throat tightness and hives at 12:14. Epinephrine is given at 12:17. What is the reaction time from first symptoms to epinephrine?
- 2 An emergency plan says to call 911 immediately after using an auto-injector. If epinephrine is given at 3:42 and the call is made at 3:45, how many minutes passed before emergency services were contacted?
- 3 A student with a known peanut allergy develops widespread hives, vomiting, and trouble breathing after lunch. Explain why epinephrine and emergency medical help are more appropriate than simply waiting or taking only an antihistamine.