TABLE 4.

Diagnostic Criteria for Anaphylaxis³

The presence of any 1 of these 3 criteria indicates that anaphylaxis is highly likely:

1. Acute onset of an illness (over minutes to several hours) involving skin, mucosal tissue, or both (eg, generalized hives, pruritus or flushing, swollen lips-tongue-uvula) and at least 1 of the following:

Respiratory compromise (eg, dyspnea, wheeze-bronchospasm, stridor, reduced peak expiratory flow rate, hypoxemia)

Reduced blood pressure or associated symptoms of end-organ dysfunction (eg, hypotonia [circulatory collapse], syncope, incontinence) or

2. ≥2 of the following that occur rapidly after exposure to a likely allergen for that patient (minutes to several hours):

Involvement of the skin-mucosal tissue (eg, generalized hives, itch-flush, swollen lips-tongue-uvula)

Respiratory compromise (eg, dyspnea, wheeze, bronchospasm, stridor, reduced peak expiratory flow rate, hypoxemia)

Reduced blood pressure or associated symptoms of end-organ dysfunction (eg, hypotonia, syncope, incontinence)

Persistent gastrointestinal symptoms (eg, crampy abdominal pain, vomiting) or

3. Reduced blood pressure after exposure to a known allergen for that patient (minutes to several hours); in infants and children, reduced blood pressure is defined by the following:

Low systolic blood pressure (age-specific) or >30% decrease in systolic blood pressure

Low systolic blood pressure is defined as follows:

<70 mm Hg for ages 1 mo to 1 y

<(70 mm Hg plus twice the age) for ages 1–10 y

<90 mm Hg for ages 11–17 y

Note that in infants and young children, hypotension may be a late manifestation of hypovolemic shock. Tachycardia, in the absence of hypotension, also may indicate shock.⁷³