Differentiation Syndrome and Sweet Syndrome‐Like Overlap Following Venetoclax–Azacytidine and G‐CSF Therapy

ABSTRACT Differentiation syndrome (DS) and Sweet syndrome (SS) are inflammatory complications mediated by cytokine dysregulation, classically associated with therapies that promote myeloid differentiation or cytokine release. While DS has been primarily linked to all‐trans retinoic acid (ATRA) and IDH inhibitors, recent evidence suggests that hypomethylating agents (HMAs), venetoclax (VEN), and granulocyte colony‐stimulating factor (G‐CSF) may also precipitate similar reactions. We report a unique case of overlapping DS and SS occurring during VEN–azacytidine (AZA) and G‐CSF therapy in a patient with relapsed acute myeloid leukaemia (AML) following allogeneic hematopoietic stem cell transplantation (allo‐HSCT). To our knowledge, this is the first description capturing the clinical, dermoscopic, histopathologic, and pathomechanism spectrum of this emerging pattern of adverse events in AML.