Neutrophilic dermatoses and autoinflammatory diseases with skin involvement--innate immune disorders

Neutrophilic dermatoses (NDs) such as Sweet's syndrome and pyoderma gangrenosum were first described more than 50 years ago and grouped based on their clinical features combined with the typical, neutrophil-rich cutaneous inflammation. In contrast, the recently identified autoinflammatory diseases (ADs) that are also associated with neutrophil granulocyte infiltration of the skin were first characterized based on their genetic architecture. Though both the older ND and the newer AD encompass distinct conditions, they can be seen as parts of a spectrum of innate inflammation. Both groups of diseases show so many overlapping clinical, pathogenetic, histologic, and genetic features that together they should likely be considered as innate immune disorders.