Table 4.

Diagnostic Criteria for Mast Cell Activation Syndrome

Criteria 1 (clinical criteria)	Episodic acute onset of symptoms with involvement of ≥2 of the 4 organ systems listed below: Cardiovascular: tachycardia, lightheaded- ness, hypotension, syncope Cutaneous: urticaria, angioedema, flushing, pruritus Digestive: abdominal cramps, diarrhea, vomiting Upper and/or lower respiratory: nasal congestion, sneezing, shortness of breath, wheezing, inspiratory stridor, hypoxia
Criteria 2 (laboratory criteria)	Event-related increase in serum tryptase above the individual’s sBT, must be evaluated within 4 hours of the event Calculate using the following formula: sBT + 20% of sBT = (120% of sBT) + 2 ng/mL
Criteria 3 (medication response criteria)	Symptomatologic improvement when using drugs that target mast cells, mast cell mediator production, and/or mast cell mediator effects Drugs: antihistamines, leukotriene modifiers, cyclooxygenase inhibitors, mast cell–stabilizing agents

sBT, serum baseline tryptase. Adapted from Gülen et al.¹⁷