Anaphylaxis Statistics

Anaphylaxis Prevalence

Between 1.6 and 5.1% of the United States Population have experienced anaphylaxis 9

Definition of Anaphylaxis

Anaphylaxis is a sudden onset of severe and potentially life-threatening symptoms that occur within minutes to hours of exposure to an allergen 1

Causes of Anaphylaxis

Anaphylaxis is caused by exposure to a trigger or allergen.  The most common triggers include 2:

• Foods (31%) 9
  • Peanuts or tree nuts 3
  • Cow’s milk 3
  • Hen’s egg 3
• Medication (34%) 9
  • Non-steroidal anti-inflammatories (NSAIDs) are responsible for 48.7–57.8% of incidents 6
  • Antibiotics 4
• Insect sting (20%) 9
  • Bees, wasps, hornets, or yellow jackets 5
  • Fire ants 5

In infants, food accounts for 73% of anaphylaxis symptoms. The most common trigger foods are egg, milk, peanut, and banana.  Drugs account for 20% of anaphylaxis cases in infants, followed by unknown triggers. 13

Symptoms

Symptoms may affect the skin, respiratory system mucosal system (tongue, lips, throat), gastrointestinal system, and cardiovascular system 1

• 80-90% of patients report subjective or general symptoms and skin issues 4
• 62% develop hives 4
• 53% develop angioedema (swelling of the mucous membranes, such as the tongue, lips or throat) 4
• 27% develop vomiting 4
• 24% report nausea 4
• 16% report abdominal pain or cramping 4
• 5% develop diarrhea 4

Treatment of Anaphylaxis

• Primary Treatment: Epinephrine should be the first treatment for anaphylaxis.  It should be administered as soon as symptoms develop, with the preferred method being intramuscular injection 7
• Secondary Treatments – there is no substitute for epinephrine, but other treatments may help manage symptoms.  These may include:
  • H1 antihistamines such as cetirizine or diphenhydramine, though the latter may be more sedating.  These may help reduce itching and hives 7
  • H2 antihistamines such as ranitidine or famotidine may be used in conjunction with an H1 antihistamine to reduce symptoms 7
  • Bronchodilators such as albuterol may help in individuals experiencing bronchospasm 7
  • Glucocorticoids have been commonly given, but there is little evidence that these are beneficial 8
• Supportive Treatment:  Focus is to manage airway, breathing and circulation. These may include:
  • Positioning to provide circulation to vital organs while ensuring airway is maintained 7
  • Supplemental oxygen 7
  • Insertion of intravenous catheters which can be used to administer medication and fluids 7
  • Monitoring of heart rate, blood pressure, respirations, oxygen level 7
  • Maintaining airway, which may require intubation 7
  • Cardiopulmonary resuscitation (CPR) when necessary 7

Anaphylaxis Morbidity and Mortality

• Most people report more 2 or more prior episodes of anaphylaxis 9
• 19% report more than 5 episodes 9
• 42% sought treatment within 15 minutes of the onset of symptoms 9
• 34% went to the hospital 9
• 27% treated themselves with antihistamines 9
• 11% self-administered epinephrine 9
• 10% called 911 9
• The fatality rate for an anaphylactic reaction in the United States is about 0.3% 10

School Children and Anaphylaxis

• Approximately 10% of schools reported anaphylactic events in the 2013-2014 school year 11
  • 44.9% occurred in high school students 11
  • 18.9% occurred in middle school students 11
  • 32.5% in elementary school students 11
  • 22% of events were in students with no known allergies 11
  • Food is the most common trigger (60%) 11
  • Unknown trigger in 21.6% of cases 11
• All 50 states permit students to carry and self-administer epinephrine 11
• Many schools provide training on identifying anaphylaxis:
  • 37.3% for the school nurse and select staff 11
  • 30.4% provided training for all staff 11
  • 28.2% for most staff 11
  • 2.0% for only the school nurse 11
• Schools often limit who can administer epinephrine:
  • 55% school nurse and select trained staff 11
  • 21.5% all staff 11
  • 15.6% most staff 11
  • 3% school nurse only 11

Economic Burden of Anaphylaxis

• The direct costs associated with anaphylaxis are $1.2 billion annually 12
  • $294 million for epinephrine alone 12
• Indirect costs associated with anaphylaxis are $609 million annually 12 Includes loss of work productivity 12

References

1. 1. https://www.aaaai.org/Aaaai/media/MediaLibrary/PDF%20Documents/Practice%20and%20Parameters/2015-Anaphylaxis-PP-Update.pdf
   2. https://onlinelibrary.wiley.com/doi/10.1111/all.12437
   3. https://onlinelibrary.wiley.com/doi/10.1111/all.12272
   4. https://www.researchgate.net/publication/281311091_Anaphylaxis_in_AdolescentAdult_Patients_Treated_in_the_Emergency_Department_Differences_Between_Initial_Impressions_and_the_Definitive_Diagnosis
   5. https://www.aaaai.org/Aaaai/media/MediaLibrary/PDF%20Documents/Practice%20and%20Parameters/Insect-hypersensitivity-2011.pdf (3/15/20)
   6. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5446992/ (3/15/20)
   7. https://www.uptodate.com/contents/anaphylaxis-emergency-treatment (3/21/20)
   8. https://www.ncbi.nlm.nih.gov/pubmed?term=22513951 (3/21/20)
   9. https://www.ncbi.nlm.nih.gov/pubmed/24144575 (3/21/20)
   10. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3972293/ (3/21/20)
   11. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5314730/ (3/21/20)
   12. https://www.ingentaconnect.com/content/ocean/aap/2012/ 00000033/00000004/art00012;jsessionid=203st4xj13im5.x-ic-live-01
   13. https://www-clinicalkey-com.ezproxy.library.tufts.edu/#!/content/playContent/1-s2.0-S108112061830783X?returnurl=null&referrer=null