A case of Sweet's syndrome following septic pulmonary emboli after high-dose chemotherapy for advanced testicular cancer

Insights Into the Pathogenesis of Sweet's Syndrome

Sweet's syndrome, also known as Acute Febrile Neutrophilic Dermatosis, is a rare inflammatory condition. It is considered to be the prototype disease of neutrophilic dermatoses, and presents with acute onset dermal neutrophilic lesions, leukocytosis, and pyrexia. Several variants have been described both clinically and histopathologically. Classifications include classic Sweet's syndrome, malignancy associated, and drug induced. The cellular and molecular mechanisms involved in Sweet's syndrome have been difficult to elucidate due to the large variety of conditions leading to a common clinical presentation. The exact pathogenesis of Sweet's syndrome is unclear; however, new discoveries have shed light on the role of inflammatory signaling, disease induction, and relationship with malignancy. These findings include an improved understanding of inflammasome activation, malignant transformation into dermal infiltrating neutrophils, and genetic contributions. Continued investigations into effective treatments and targeted therapy will benefit patients and improve our molecular understanding of inflammatory diseases, including Sweet's syndrome.

Drug-induced Sweet's syndrome

OBJECTIVE

To systematically review the pertinent literature on drug-induced Sweet's syndrome (SS).

DATA SOURCES

MEDLINE (1966-December 2006), International Pharmaceutical Abstracts (1970-December 2006), Science Citation Index (1945-December 2006), and EMBASE (1980-December 2006) were searched using the key terms Sweet's syndrome, drug-induced, and acute neutrophilic dermatitis.

STUDY SELECTION AND DATA EXTRACTION

All case reports of drug-induced SS located using the above databases were collected for causality assessment. In addition, relevant articles regarding the various causes and presentations of SS were selected to provide background information. Bibliographies of all relevant articles were reviewed for additional citations.

DATA SYNTHESIS

All case reports of drug-induced SS were evaluated against an expanded Naranjo scale with specific criteria for SS. Tables were developed listing key criteria for evaluating the case reports for causality. Data were evaluated by quantity and quality of evidence, and an assessment was made as to whether there was a feasible pharmacologic mechanism to explain causality.

CONCLUSIONS

Granulocyte colony-stimulating factor (G-CSF), all-trans retinoic acid (ATRA), and vaccines met 2 of 3 criteria for an association with SS. There are sufficient data and a plausible pharmacologic mechanism for G-CSF and ATRA. Vaccines meet the qualitative criteria and also have a plausible pharmacologic mechanism. The evidence regarding minocycline is of high quality; however, the quantity of evidence and a reasonable pharmacologic mechanism are lacking. A host of miscellaneous drugs have also been implicated in causing the disorder, all without sufficient evidence.