Major Criteria:
(1) abrupt onset of painful, erythematous plaques and nodules
(2) histopathologic evidence of a dense neutrophilic infiltrate in the dermis without evidence of leukocytoclastic vasculitis
Features of Classic Sweet's Syndrome:
(3) pyrexia > 38°C
(4) associated condition
(4a) an underlying hematologic or visceral malignancy
(4b) an inflammatory disease
(4c) pregnancy
(4d) following an upper respiratory or gastrointestinal infection
(4e) following a vaccination
(5) excellent response to treatment with systemic glucocorticoids or potassium iodide
(6) abnormal laboratory tests at presentation, with 3 or more of the following:
(6a) ESR > 20 mm/h
(6b) increased C-reactive protein
(6c) WBC count > 8,000 per µL
(6d) neutrophils in differential > 70%
Features of drug-induced Sweet's syndrome:
(7) pyrexia > 38°C
(8) drug associated
(8a) temporal relationship between drug ingestion and clinical presentation
(8b) recurrence after oral rechallenge
(9) temporally-related resolution of lesions after drug withdrawal
Interpretation:
• diagnosis of classic Sweet's syndrome: 1 + 2 + (2 or more from 3, 4, 5, 6)
• diagnosis of drug-induced Sweet's syndrome: 1 + 2 + 7 + 8 + 9
