Successful treatment of idiopathic mast cell activation syndrome with low‐dose Omalizumab

Objectives Idiopathic mast cell disorders, a recently defined and recognised syndrome in clinical practice, are similar to the previously termed non‐clonal mast cell disorder. Patients with idiopathic mast cell activation syndrome (MCAS) suffer all the classical signs of mast cell activation but do not have evidence of mast cell clonality. Furthermore, treatment of these patients can be limited and burdensome in those with refractory symptoms.