Neutrophilic dermatoses: an update.

Neutrophilic dermatoses constitute a heterogeneous group of dermatologic diseases, which are unified by the predominance of neutrophils within the inflammatory infiltrate on histopathology. The aims of this review were to provide an update on the clinical and histologic presentation of the main neutrophilic dermatoses and to develop a guide for clinical practice. A structured literature search of PubMed, Medline, and Embase was performed, using the key words "neutrophilic disorders", "cutaneous small vessel vasculitis", "Sweet's syndrome", "bowel associated dermatosis arthritis syndrome", "Behcet's", "palisaded neutrophilic and granulomatous dermatosis", "rheumatoid neutrophilic dermatitis", and "pyoderma gangrenosum". Related articles were screened for key terms and were included if appropriate. This group contains a wide spectrum of unique disorders, each with its own histologic and clinical subtleties, making specific diagnosis of a given entity within the group diagnostically challenging. The fact that overlapping forms of neutrophilic dermatoses, which share features of multiple neutrophilic dermatoses, are not uncommon makes the diagnoses more challenging.