This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
First Aid for Allergic Reactions
An allergic reaction occurs when the immune system overreacts to a foreign substance such as food, insect stings, medications, or latex. Symptoms can range from mild itching and hives to anaphylaxis, a life-threatening emergency that impairs breathing and blood circulation. Prompt recognition and immediate intervention are critical to prevent fatal complications.
Quick Summary
Identify whether the reaction is mild or severe; administer an epinephrine auto-injector and call emergency services immediately if breathing difficulties, swelling, or systemic symptoms arise.
Important Medical Disclaimer
This guide is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult with qualified healthcare providers for medical concerns.
Step-by-Step Guide
Assess the severity of symptoms
Quickly determine whether the reaction is localized or systemic. Mild reactions typically involve localized itching, redness, sneezing, or a few hives. Severe reactions (anaphylaxis) involve widespread hives, swelling of the face, lips, tongue, or throat, wheezing, shortness of breath, dizziness, vomiting, or collapse.
Important: Anaphylaxis can develop rapidly within seconds to minutes of exposure; do not wait to see if symptoms improve on their own.
Eliminate further allergen exposure
Safely remove the patient from the source of the allergen if it is known and feasible. If caused by an insect sting, gently scrape the stinger off using a firm edge like a credit card rather than squeezing with tweezers. If caused by food or oral medication, spit out any remaining residue and avoid swallowing.
Administer epinephrine immediately for severe reactions
If the person shows signs of anaphylaxis, use an epinephrine auto-injector (such as an EpiPen, Auvi-Q, or generic device) without delay. Press the injector firmly against the outer mid-thigh at a 90-degree angle until the mechanism clicks, and hold it in place for the duration instructed on the device (typically 2 to 3 seconds). Epinephrine can be administered directly through clothing if necessary.
Important: Epinephrine is the only first-line medication capable of reversing airway constriction and cardiovascular collapse during anaphylaxis; oral antihistamines are not a substitute.
Call emergency medical services
Call 911 or your local emergency number immediately after administering epinephrine, or assign a specific bystander to call while you assist the patient. Inform the dispatcher that the individual is experiencing an anaphylactic reaction and whether an auto-injector was delivered. Request advanced life support transport to the nearest emergency department.
Position the person safely
Help the person lie flat on their back and elevate their legs approximately 12 inches to maintain blood flow to vital organs. If they are vomiting, coughing up fluid, or unconscious, place them in the recovery position on their side to keep the airway clear. If severe breathing difficulty makes lying down intolerable, allow them to remain seated upright, but avoid sudden standing.
Important: Do not allow a person experiencing anaphylaxis to suddenly stand or walk, as this can cause a rapid drop in blood pressure and cardiac arrest.
Treat mild symptoms appropriately
If the person has only localized symptoms with no breathing difficulty, dizziness, or swelling of the face or throat, an oral non-sedating antihistamine (such as cetirizine or loratadine) can help relieve itching and hives. Apply a cool, damp cloth to itchy or inflamed skin to reduce discomfort. Continue observing the person closely for at least one to two hours, as mild reactions can escalate.
Important: Never give oral medications, fluids, or food to someone who is having trouble breathing, swallowing, or experiencing reduced consciousness.
Monitor vitals and prepare a second dose
Stay with the individual and monitor their breathing, alertness, and pulse continuously until emergency responders arrive. If symptoms fail to improve or worsen after 5 to 15 minutes and paramedics have not arrived, administer a second epinephrine auto-injector in the opposite thigh if one is available. Keep used auto-injectors safe to hand over to emergency personnel.
Frequently Asked Questions
Can I give an antihistamine instead of an EpiPen during anaphylaxis?
What is a biphasic allergic reaction?
What should I do if an auto-injector is expired?
Should someone go to the hospital if they feel fine after using epinephrine?
Sources & References
- 1
- 2MedlinePlus: AnaphylaxisSource
- 3NHS: AnaphylaxisSource
- 4
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed October 19, 2026. · Read our editorial policy