Characterized chiefly by hypereosinophilia and angioedema, Gleich syndrome is a rare disorder with unclear clinical and therapeutic findings. Other symptoms include increased IgM levels, weight gain, fever, and urticaria. Herein we review Gleich syndrome and assess clinical features, epidemiology, and treatment options. Thirty-two articles including case reports or case series of eosinophilic angioedema and Gleich syndrome were included. Data regarding patient age, gender, and history, clinical and biological manifestations, and treatment protocols were recorded. The most common clinical findings include recurrent or non-recurrent angioedema, fever, urticaria, weight gain, blood eosinophilia, and elevated immunoglobulin levels. Corticosteroid therapy is the mainstay of treatment. Gleich syndrome is a distinctive hypereosinophilic entity with a benign course and good response to systemic corticosteroids. More studies are needed to evaluate the pathophysiology of this syndrome and lead to better therapeutic options.