Table 4.

Clinical criteria for diagnosing anaphylaxis [16,17]

Anaphylaxis is highly likely when any 1 of the following 3 criteria is fulfilled following exposure to an allergen:
1	Acute onset of an illness (minutes to several hours) with involvement of the skin, mucosal tissue, or both (e.g., generalized hives, pruritus or flushing, swollen lips-tongue-uvula) and at least 1 of the following: a. Respiratory compromise (e.g. dyspnea, wheeze, bronchospasm, stridor, reduced PEF, hypoxemia) b. Reduced BP or associated symptoms of end-organ dysfunction (e.g. hypotonia [collapse], syncope, incontinence)
2	2 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-mucosal tissue (e.g., generalized hives, itch-flush, swollen lips-tongue-uvula) b. Respiratory compromise (e.g., dyspnea, wheeze, bronchospasm, stridor, reduced PEF, hypoxemia) c. Reduced BP or associated symptoms (e.g., hypotonia [collapse], syncope, incontinence) d. Persistent GI symptoms (e.g., painful abdominal cramps, vomiting)
3	Reduced BP after exposure to a known allergen for that patient (minutes to several hours): a. Infants and children: low systolic BP (age specific) or > 30% decrease in systolic BP* b. Adults: systolic BP < 90 mmHg or > 30% decrease from that person’s baseline

PEF = Peak expiratory flow; BP: blood pressure; GI: gastrointestinal

* Low systolic blood pressure for children is age specific and defined as: < 70 mmHg for age 1 month to 1 year; < 70mmHg + [2 x age] for age 1 to 10 years; < 90mmHg for age 11 to 17 years.