Table 1.

Clinical criteria for the diagnosis of anaphylaxis NIAID/FAAN of 2005 and WAO of 2019

Second National Institute of Allergy and Infectious Diseases/Food Allergy and Anaphylaxis Network (NIAID/FAAN) symposium, 2005 [Sampson JACI, 2006; 391-7]	WAO Anaphylaxis Committee, 2019 [Turner PJ, WAO, 2019 :100066.]
One of the three following criteria is fulfilled:	One of the two following criteria is fulfilled:
1. Acute onset of an illness (minutes to several hours) with involvement of the skin, mucosal tissue or both (e.g. generalized hives, itching or flushing, swollen lips-tongue-uvula) AND AT LEAST ONE OF THE FOLLOWING a. Respiratory disorder (e.g. dyspnoea, wheeze, bronchospasm, stridor, decreased PEF value, hypoxemia) b. Reduced blood pressure or symptoms of end-organ dysfunction (hypotonia [collapse], syncope, urinary incontinence)	1. Acute onset of an illness (minutes to several hours) with involvement of the skin, mucosal tissue or both (e.g. generalized hives, itching or flushing, swollen lips-tongue- uvula) AND AT LEAST ONE OF THE FOLLOWING a. Respiratory disorder (e.g. dyspnoea, wheeze, bronchospasm, stridor, decreased PEF value, hypoxemia) b. Reduced blood pressure or symptoms of end-organ dysfunction (hypotonia [collapse], syncope, urinary incontinence)
2. Two or more of the following situations that occur suddenly after exposure to a likely allergen for that patient (minutes to several hours): a. Involvement of the skin, mucosal tissue or both (e.g. generalized hives, itching or flushing, swollen lips-tongue-uvula) b. Respiratory disorder (e.g. dyspnoea, wheeze, bronchospasm, stridor, decreased PEF value, hypoxemia) c. Reduced blood pressure or symptoms of end-organ dysfunction (hypotonia [collapse], syncope, urinary incontinence) d. Persistent gastrointestinal symptoms (e.g. crampy abdominal pain, vomiting)	c. Severe gastrointestinal symptoms (e.g. acute crampy abdominal pain, recurrent vomiting), especially after exposure to the allergen other than food)
3. Reduced blood pressure after exposure to a likely allergen for that patient (minutes to several hours): a. Infants and children: low systolic blood pressure (age specific) or greater than 30% of decrease in systolic BP b. Adults: systolic BP of less than 90 mm Hg or greater than 30% decrease from that person’s baseline	2. Acute onset of hypotension1 or bronchospasm or laryngeal edema2 right after exposure to a known or a highly probable allergen3 for that patient (minutes to several hours4), even with absence of typical involvement of the skin

^1.Low systolic blood pressure – a decrease in systolic blood pressure greater than 30% from that person’s baseline or in infants and children under age of 10: systolic BP less than (70 mm Hg + [2 × age in years] or in older children or adults – systolic blood pressure less than 90 mm Hg.

^2.Laryngeal symptoms comprise: stridor, voice change, odynophagia.

^3.Allergen is a substance (usually protein) capable of triggering immunological response, which may lead to an allergic reaction. Most allergens act by route which IgE is the mediator for, but some non-allergen triggers may act independently of IgE (for instance by a direct mast cell activation).

^4.Most allergic reactions occur within 1–2 h from exposure, usually much faster. Reactions can be delayed in case of some food allergens (e.g. alpha-gal) or in the context of immunotherapy, up to 10 h following exposure.