Systemic Mast Cell Activation

**Semantic type:** Finding

**Definition:** Clinical signs and symptoms resulting from aberrant mast cell mediator release. These are episodic and involve two or more organ systems, including: dermatologic: urticaria, angioedema, and flushing; gastrointestinal: nausea, vomiting, diarrhea, and cramping; cardiovascular: hypotension, syncope, and tachycardia; respiratory: wheezing; naso-ocular: nasal congestion and conjunctival injection; immunologic: recurrent anaphylaxis.