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 and swollen lips-tongue-uvula) and at least one of the following:

a) Respiratory compromise (e.g. dyspnea, wheeze-bronchospasm, stridor, reduced PEF and hypoxemia)

b) Reduced blood pressure (BP) or associated symptoms of end-organ dysfunction (e.g. hypotonia/collapse, syncope and 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-mucosal tissue (e.g. generalized hives, itch-flush and swollen lips-tongue-uvula)

b) Respiratory compromise (e.g. dyspnea, wheeze bronchospasm, stridor, reduced PEF and hypoxemia)

c) Reduced BP or associated symptoms (e.g. hypotonia/collapse, syncope and incontinence)

d) Persistent gastrointestinal symptoms (e.g. cramping abdominal pain, 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 greater than 30% decrease in systolic BP.

b) Adults: systolic BP of less than 90 mm Hg or greater than 30% decrease from that person’s baseline.