Sweet syndrome in patients with and without malignancy: A retrospective analysis of 83 patients from a tertiary academic referral center

Background Sweet syndrome is a neutrophilic dermatosis that may be categorized into classic, malignancy-associated, and drug-induced subtypes. Few studies have systematically analyzed this rare disorder. Objective To describe the clinicopathologic characteristics and treatment of Sweet syndrome and identify characteristics associated with concurrent malignancy. Methods We retrospectively reviewed patients with Sweet syndrome at the University of Pennsylvania from 2005 to 2015. Results We identified 83 patients (mean age, 57 years; 51% male) with Sweet syndrome: 30% with the classic form, 44% with the malignancy-associated form, 24% with the drug-induced form in the setting of malignancy, and 2% with the drug-induced form. Acute myeloid leukemia was the most common malignancy (in 24 of 83 patients [29%]). Filgrastim was the most common medication (used in 8 of 83 patients [10%]). Leukopenia ( P P  = .002), thrombocytopenia ( P P P  = .024) were associated with malignancy (χ 2 test). Limitations This was a retrospective study that represents patients from a single tertiary academic referral center, which may limit its generalizability to other settings. Conclusion When caring for patients with Sweet syndrome, dermatologists should be aware of the potential association of leukopenia, anemia, thrombocytopenia, absence of arthralgia, and histiocytoid or subcutaneous histopathology with malignancy.