Background: Sweet syndrome (acute febrile neutrophilic dermatosis) is a distinctive disorder which has four primary features: skin eruption of violaceous tender papules and plaques; biopsy showing dermal nonvasculitis neutrophilic infiltration; fever; and peripheral neutrophilia. Associated factors include infections, malignancies, drug reactions, inflammatory bowel disease and pregnancy.

Objective: To describe the characteristics and underlying causes of Sweet syndrome.

Materials and Methods: The author retrospectively examined the medical records of 9 patients who met the diagnostic criteria for Sweet syndrome in Rajavithi Hospital between 2008 and 2018.

Results: Four patients had a hematologic disorder and solid tumor, while another four had related mycobacterium and atypical mycobacterium infections. One had systemic lupus erythematosus associated with Sweet syndrome. Only one case was the classic type.

Conclusion: Sweet syndrome is diagnosed based on clinical presentation and histopathology showing neutrophilic infiltration without vasculitis. Hematologic conditions are still the main associated causes while infections, especially mycobacterium ones, are being increasingly suspected.

Keywords: Sweet syndrome, Cancer, Mycobacterium tuberculosis, Atypical mycobacterium, Systemic lupus erythematous