Abstract | November 13, 2020
Systemic Mastocytosis, a subcategory of mastocytosis, has many different extracutaneous manifestations including gastrointestinal (GI) tract involvement. While GI involvement can be deemed nonspecific due to generalized mast cell mediators from the disease, a mastocytic enterocolitis has only been recently described and studied. This case presents a 65-year old male with a six-month history of chronic diarrhea as well as severe allergic reactions who was diagnosed with mastocytic enterocolitis after endoscopy. A trial therapy with omalizumab was successfully used as treatment for both the GI and systemic manifestations of mastocytosis.