Anaphylaxis
A rapid, life-threatening allergic reaction requiring immediate medical care.
Anaphylaxis is a serious and potentially fatal allergic reaction that can progress rapidly, typically causing multiple symptoms such as an itchy rash, throat swelling, shortness of breath, vomiting, lightheadedness, loss of consciousness, low blood pressure, and medical shock. Symptoms usually start within minutes to hours and escalate quickly to life-threatening levels, requiring urgent medical treatment even if symptoms appear to improve. Common causes include allergies to insect stings, foods (nuts, peanuts, milk, fish, eggs), medications (antibiotics, NSAIDs), anaesthetics, latex, physical exercise, and sometimes unknown triggers. The condition involves a rapidly escalating release of inflammatory mediators from white blood cells, and diagnosis is based on symptoms after exposure to a potential allergen.
- field
- Medicine
- known_for
- Severe, rapid allergic reaction requiring urgent epinephrine treatment
- global_prevalence
- 0.05–2% of population experience at some point in life
- survival_rate_in_US
- 99.7% of hospitalized patients survive
- common_triggers
- Insect venom, foods, medications, latex, exercise
- primary_treatment
- Epinephrine injection, intravenous fluids, reclining position with feet elevated
Lore & Background
Anaphylaxis derives from Ancient Greek words meaning 'up' and 'protection'. It typically presents with symptoms affecting the skin (80–90%), respiratory system (70%), gastrointestinal tract (30–45%), heart and vasculature (10–45%), and central nervous system (10–15%), with two or more areas involved. Skin symptoms include hives, itchiness, flushing, or swelling (angioedema), while respiratory signs include shortness of breath, wheezing, or stridor. Cardiovascular effects may include low blood pressure, shock, or in rare cases, coronary artery spasm leading to heart attack or cardiac arrest. Gastrointestinal symptoms can involve severe crampy abdominal pain and vomiting, and some people experience a sense of impending doom.
Reader's Guide
Anaphylaxis is a critical medical emergency recognized worldwide, with an estimated 0.05–2% of the population experiencing it at some point. Its significance lies in its rapid progression and potential fatality, yet with prompt treatment—primarily epinephrine injection, intravenous fluids, and positioning—survival rates are high (99.7% in U.S. hospitals). The condition underscores the importance of carrying epinephrine autoinjectors and seeking immediate emergency services regardless of on-site treatment. Common triggers vary by age and region: foods are most common in children and young adults, while medications and insect stings prevail in older adults. Idiopathic cases account for 32–50% of occurrences. The increasing recognition and declining underreporting into the 2010s suggest the condition may be more common than previously thought. Understanding anaphylaxis has led to improved management guidelines, including the use of epinephrine as first-line therapy and the recommendation for patients to carry autoinjectors and medical identification.
Did You Know?
- The word 'anaphylaxis' comes from Ancient Greek meaning 'up' and 'protection'.
- Symptoms typically begin within 5 to 30 minutes if the trigger is intravenous, and up to 2 hours if from food.
- About 99.7% of people hospitalized with anaphylaxis in the United States survive.
- Physical exercise can trigger anaphylaxis, sometimes in combination with certain foods (food-dependent exercise-induced anaphylaxis).
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