From the Guidelines
Anaphylaxis is a life-threatening condition that requires immediate administration of epinephrine, and patients experiencing anaphylaxis should use epinephrine immediately and call emergency services, as delayed administration increases mortality risk. Anaphylaxis occurs at an estimated rate of 2.1 cases per 1,000 person-years in the United States, affecting approximately 1 in 500 Americans annually 1. The first-line treatment for anaphylaxis is epinephrine (adrenaline), typically administered as an intramuscular injection using an auto-injector (such as EpiPen or Auvi-Q) at a dose of 0.3mg for adults or 0.15mg for children, as endorsed by the 2024 American Heart Association and American Red Cross guidelines for first aid 1.
Some key points to consider in the management of anaphylaxis include:
- Early administration of intramuscular epinephrine is crucial, regardless of the triggering agent 1
- Patients with anaphylaxis may require additional treatments, such as endotracheal intubation, intravenous fluids, vasopressors, and other advanced treatments to survive 1
- Secondary treatments, including antihistamines (like diphenhydramine 25-50mg) and corticosteroids, should never replace epinephrine as the primary intervention
- People with known severe allergies should carry epinephrine auto-injectors at all times, ensure they're not expired, and know how to use them properly
It is essential to note that anaphylaxis can be identified using the NIAID/FAAN diagnostic criteria, which incorporate features related to the onset of the reaction, exposure to an inciting trigger, as well as signs and symptoms 1. However, the role of clinical judgment is crucial in the management of anaphylaxis, and epinephrine administration should not be limited to those patients meeting the diagnostic criteria.
From the Research
Anaphylaxis Incidence in the United States
- The incidence of anaphylaxis in the United States is estimated at 2.1 per 1,000 person-years, as reported by 2.
- This condition is a life-threatening systemic reaction that can occur within one to two hours of exposure to an allergen.
- Anaphylaxis can be triggered by various factors, including medications, stinging insect venoms, and foods, with unidentified triggers occurring in up to one-fifth of cases.
Prevalence and Characteristics of Anaphylaxis
- A study published in 3 estimated that the prevalence of anaphylaxis in the general population is at least 1.6% and probably higher.
- The most common triggers reported were medications (34%), foods (31%), and insect stings (20%), as found in 3.
- Patients with anaphylaxis often do not receive adequate treatment, with 52% having never received a self-injectable epinephrine prescription, and 60% not currently having epinephrine available, as reported in 3.
Management and Treatment of Anaphylaxis
- The management of anaphylaxis involves removal of the trigger, early administration of intramuscular epinephrine, and supportive care for the patient's airway, breathing, and circulation, as stated in 2 and 4.
- Adjunct medications, such as histamine H1 and H2 antagonists, corticosteroids, beta2 agonists, and glucagon, should only be considered after epinephrine administration, as recommended in 2.
- Patients should be monitored for a biphasic reaction, which can occur within four to 12 hours, depending on risk factors for severe anaphylaxis, as noted in 2.
Epidemiology of Anaphylaxis
- Anaphylaxis is a potentially life-threatening allergic reaction that can affect both children and adults in the United States, as discussed in 5 and 6.
- The available literature suggests that there are approximately 1500 annual deaths from anaphylaxis, and between 2.8 million and 42.7 million Americans are at risk of experiencing an episode of anaphylaxis during their lives, as estimated in 5.
- The occurrence of anaphylaxis in the US is not as rare as is generally believed, with estimates suggesting that it may affect 1.21% to 15.04% of the US population, as calculated in 6.