Sweet's syndrome represents the epitome of the neutrophilic dermatosis, a group of reactive cutaneous diseases characterized histopathologically by the existence of an infiltrate composed by neutrophils. Clinically, it is characterized by the abrupt onset of tender or painful plaques accompanied by fever, general malaise, and neutrophilic leukocytosis. Sweet's syndrome is a marker of several internal conditions, especially infections, inflammatory bowel disease, autoimmune disorders, and malignant neoplasm (predominantly of hematological origin). Sweet's syndrome reflects a neutrophilic reaction that affects the skin and sometimes internal organs. For this reason it is important to reach a correct diagnosis and assess appropriately both the triggering factors and the concomitant internal involvement. There are several therapeutic approaches that achieve either the resolution or the satisfactory management of this condition.