IGHE and systemic mastocytosis: Bossi et al. [9] highlighted that a child affected by systemic mastocytosis with persistent rash, diarrhea, abdominal pain, palpitations, musculoskeletal symptoms, fatigue, refractory to anti-H1 and oral steroids became quickly asymptomatic following administration of omalizumab, a monoclonal antibody against IgE.