When is it anaphylaxis?
Anaphylaxis is highly likely when any ONE of the three following criteria are met:
- Acute onset of an illness (minutes to several hours) with involvement of the skin, mucosal tissue, or both (generalized hives, itching or flushing, swollen lips/tongue/uvula AND AT LEAST ONE OF THE FOLLOWING:
- Respiratory compromise (difficulty breathing, wheezing, bronchospasm, stridor, reduced PEF, low oxygenation of the blood)
- Reduced blood pressure or associated symptoms of end organ dysfunction (low blood pressure, collapse, fainting, incontinence)
- Two or more of the following that occur rapidly after exposure to a LIKELY allergen for that patient (minutes to several hours)
- Involvement of skin, mucosal tissue (hives, itching, flushing, swollen lips, tongue, uvula)
- Respiratory compromise (difficulty breathing, wheezing, bronchospasm, stridor, reduced PEF, low oxygenation of the blood)
- Reduced blood pressure or associated symptoms of end organ dysfunction (low blood pressure, collapse, fainting, incontinence)
- Persistent GI symptoms (crampy abdominal pain, vomiting)
- Reduced BP after exposure to KNOWN allergen for that patient (minutes to several hours)
- Infants and children: low systolic blood pressure (age dependent) or greater than 30% decreased in systolic BP
- Adults: systolic BP of less than 90 mm Hg or greater than 30% decrease from that person’s baseline
Note: low systolic blood pressure for children is defined as less than 70 mm Hg from 1 month to 1 year, less than (70 mm Hg + [2 x age]) from 1 to 10 years, and less than 90 mm Hg from 11 to 17 years.
“When a patient fulfills any of the three criteria of anaphylaxis outlined above, the patient should receive epinephrine immediately because epinephrine is the treatment of choice in anaphylaxis. There undoubtedly will be patients who present with symptoms not yet fulfilling the criteria of anaphylaxis yet in whom it would be appropriate to initiate therapy with epinephrine, such as a patient with a history of near-fatal anaphylaxis to peanut who ingested peanut and within minutes is experiencing urticaria and generalized flushing.”
Reference: Sampson HA et al. J Allergy Clin Immunol 2006; 117:391-7
How can I recognize anaphylaxis in someone else (including children or non-verbal persons?)
Symptoms that can be recognized without self reporting:
Skin and mucus membranes: sudden onset hives, angioedema (swelling of the face, tongue, mouth and throat)
Respiratory: rapid onset of coughing, choking, stridor (high pitched breath sound), wheezing, difficulty breathing, cessation of breathing, turning blue
GI: sudden, profuse vomiting
Cardiovascular: weak pulse, irregular heartbeat, sweating, clamminess, paleness, fainting, loss of consciousness
Central nervous system: sudden unresponsiveness, low muscle tone, lethargy, seizures
Reference: Simons FER. J Allergy Clin Immunol 2007; 120: 537-40.