Anaphylaxis secondary to mast cell disorder

**Definition:** Symptoms of anaphylaxis secondary to mast cell disorders result from excessive mast cell mediator release, especially histamine, and may include pruritus and flushing, abdominal pain, diarrhea, dyspnoea, tachycardia, or profound hypotension. It happens in both children and adults, but in adults it can occur even without urticaria pigmentosa lesions. Levels of basal tryptase are constantly high. Fatal anaphylaxis has been described following hymenoptera stings and in the preoperative period.