Skin-nontumor / Clinical dermatology
Other dermatoses
Sweet’s Syndrome

Author: Mowafak Hamodat, M.D., MB.CH.B, MSc., FRCPC (see Authors page)

Revised: 21 July 2016, last major update August 2011

Copyright: (c) 2002-2016, PathologyOutlines.com, Inc.

PubMed Search: Sweet’s Syndrome [title]

Cite this page: Sweets Syndrome. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/skinnontumorsweetssyndrome.html. Accessed December 8th, 2016.
Definition / General
  • Also called acute febrile neutrophilic dermatosis
  • Abrupt onset of tender or painful erythematous plaques and nodules on the face and extremities and less commonly on the trunk, in association with fever (usually), malaise and a neutrophil leukocytosis
  • Associated with AML, less often with solid malignancies
  • Often females, any age but rare in childhood
  • Unknown etiology, but may represent immunological hypersensitivity reaction
Treatment
  • Most cases respond to oral corticosteroids
  • Thalidomide was successful in one patient who failed to respond to metronidazole, dapsone and methotrexate; IV immunoglobulin was used in a child with concurrent immunodeficiency
  • Also response to 5-azacytidine in patient with myelodysplastic syndrome
  • A case of histiocytoid Sweet's syndrome was responsive to dapsone; dapsone has also been used with systemic corticosteroids in a patient who was HIV positive
Micro Description
  • Intense neutrophilic dermal infiltrate in reticular dermis, may be perivascular, diffuse and surround sweat glands; edema with marked leukocytoclasia; marked papillary edema
  • Occasional presence of dermal papillary microabscesses can result in confusion with dermatitis herpetiformis
  • Epidermis is normal, occasionally slight spongiosis, vesiculation with spongioform pustule
  • Necrotic keratinocytes may be present
  • Variable eosinophils, lymphocytes and histiocytes
  • Blood vessels are dilated and show endothelial swelling
Micro Images

Images hosted on PathOut servers:

Courtesy of Angel Fernandez-Flores, M.D., Ph.D.

Differential Diagnosis
  • Behcet's disease may be associated with lesions similar to Sweet’s syndrome
  • Gram stain and PAS exclude infection
  • Granuloma faciale: fibrinoid necrosis is minimal but eosinophils are prominent
  • Late lesions of erythema elavatum diutinum and granuloma faciale show fibrosis, not seen in Sweet’s Syndrome
  • Pyoderma gangrenosum: has ulcer, no leukorrhexis
  • Rheumatoid neutrophilic dermatitis, neutrophil-rich variant of anaplastic large cell lymphoma
  • The presence of fibrinoid vascular changes distinguishes necrotizing vasculitis such as leukocytoclastic vasculitis, erythema elevatum diutinum, and granuloma faciale from Sweet’s Syndrome
Additional References