Systemic mastocytosis is a rare pathology that can affect most systems of the human organism. Although diagnosis is often fortuitous and prognosis good in a very high percentage of cases, it can sometimes present in extremely severe and occasionally fatal forms. With the aid of the available literature, we discuss the most recent classifications, clinical features and diagnostic and therapeutic approaches to this disease. We then do an epidemiological review of the cases reported in Reggio Emilia over the past 9 years. Due to the lack of symptoms of this pathology, its reported incidence of about 0.3 new cases per 100,000 inhabitants per year is obviously underestimated. Drug therapy is purely symptomatic and does not affect its clinical evolution.