- Mast cell infiltration of organs w/various degrees dysfxn
- Episodic and along wide spectrum typically triggered by something (allergen/exposure/stress/other)
- Flushing, angioedema, itching
- Nasal congestion
- Abdominal pain, diarrhea
- Shortness of breath, chest tightness
- Tachycardia, lightheadedness, syncope
- Cutaneous findings inlcude hyperpigmented macules
- Sometimes urticaria/redness induced by rubbing an affected area (Darier's sign)
- Mastocytes on biopsy of infiltrated organs and/or bone marrow
- Elevated Tryptase level