Episode Details

Reference: . Timing of repeat epinephrine to inform paediatric anaphylaxis observation periods: a retrospective cohort study. Lancet Child & Adolescent Health. July 2025 Dr. Kammeron Brissett Guest Skeptic: Dr. Kammeron Brissett is a pediatric emergency medicine fellow at Children’s National Hospital in Washington, DC. She completed her pediatrics residency and a chief year at Rainbow Babies and Children’s Hospital in Cleveland, Ohio. Her interests include injury prevention, social determinants of health, and advocacy. Case: A 7-year-old boy with a peanut allergy presents to the emergency department (ED) after eating a cookie at a birthday party. Shortly afterwards, he developed hives and wheezing. His parents gave him an epinephrine auto-injector to improve his symptoms. In the ED, he feels much better. His vital signs are normal, and his lungs are clear. He has no other gastrointestinal or cardiovascular symptoms. The parents tell you, “Unfortunately, we’ve been through this before. It’s not the first time he has accidentally eaten something that may have had some peanuts in it. Last time, we sat in the ED for a few hours before going home. It’s been a long day. Can we just go home now?” Background:  Anaphylaxis is a serious, potentially life-threatening systemic allergic reaction with a fast onset. It is a clinical diagnosis that should be considered when: Acute illness with skin/mucosal involvement and either respiratory compromise or reduced blood pressure/end-organ symptoms; or Two or more of the following occurring rapidly after exposure: skin/mucosal involvement, respiratory compromise, reduced blood pressure, or persistent gastrointestinal symptoms; or Reduced blood pressure after exposure to a known allergen for the patient. Early recognition and treatment with intramuscular epinephrine is crucial. Sometimes, even after initial symptom improvement with IM epinephrine, anaphylaxis symptoms can recur even without exposure to the known trigger. This is called a biphasic reaction and can happen up to 72 hours later. The SGEM discussed anaphylaxis and biphasic reactions 13 years ago on SGEM#57. The bottom line was that prolonged observation is likely unnecessary in patients whose symptoms resolve with therapy in the ED. Biphasic reactions are rare and can occur anywhere from 10 minutes up to 6 days. We already have problems with boarding and overcrowding. We can’t keep all patients with anaphylaxis for 6 days. So, when can we send them home? Traditionally, ED observation after anaphylaxis has been around 4 to 6 hours to monitor for biphasic reactions. The Resuscitation Council UK recommends a risk-stratified approach: A patient can be discharged after 2 hours when there’s a good response to a single dose of epinephrine, the symptoms have resolved, the child and family has another epinephrine autoinjector and knows how to use it, and has adequate supervision after discharge. They recommend at least 6 hours of observation if two IM doses of epinephrine were needed or there was a prior biphasic reaction. Finally, they recommend at least 12 hours observation if there was severe respiratory compromise, >2 doses of epinephrine, ongoing allergen absorption, late-night presentation/limited access to care, or difficult access to emergency services. The National Institute for Care and Health Excellence (NICE) is even a bit more conservative, recommending any child under age of 16 with suspected anaphylaxis be admitted. What about in the US? In the United States, the 2023 AAAAI/ACAAI Joint Task Force Practice Parameter (JTFPP) emphasizes individualized, risk-based observation and shared decision-making, noting that risk for biphasic reactions is higher with more severe initial reactions and when >1 dose of epinephrine is required. It also highlights that patients with a prompt, complete, and durable response to epinephrine may not always require activation of EMS or prolonged monitoring, underscoring tailored dispos