Table 1.

National Institute of Allergy and Infectious Disease and Food Allergy and Anaphylaxis Network criteria for anaphylaxis

Anaphylaxis is likely when any one of these three criteria is fulfilled:
1. Acute onset of illness (minutes to several hours) with involvement of the skin, mucosal tissue, or both (e.g., generalized hives, pruritus or flushing, swollen lips, tongue, or uvula)
and at least one of the following:
(a) Respiratory compromise (e.g., dyspnea, wheeze or bronchospasm, stridor, reduced peak expiratory flow, hypoxemia)
(b) Reduced blood pressure or associated symptoms of end-organ dysfunction (e.g., hypotonia [collapse], syncope, incontinence)
2. Two or more of the following that occur rapidly after exposure to a likely allergen for that patient (minutes to several hours):
(a) Involvement of the skin or mucosal tissue (e.g., generalized hives, itch or flush, swollen lips, tongue, or uvula)
(b) Respiratory compromise (e.g., dyspnea, wheeze or bronchospasm, stridor, reduced peak expiratory flow, hypoxemia)
(c) Reduced blood pressure or associated symptoms (e.g., hypotonia [collapse], syncope, incontinence)
(d) Persistent gastrointestinal tract symptoms (e.g., crampy abdominal pain, vomiting)
3. Reduced blood pressure after exposure to known allergen for that patient (minutes to several hours):
(a) Infants and children: low systolic blood pressure (age specific) or >30% decrease in systolic blood pressurea
(b) Adults: systolic blood pressure <90 mmHg or >30% decrease from that person’s baseline

^a Low systolic blood pressure for children is defined as <70 mmHg from 1 month to 1 year, < (70 mmHg + [2 × age]) from 1 to 10 years, and <90 mmHg from 11 to 17 years.

Modified from Sampson et al. [7]