Pathophysiology of Pyoderma Gangrenosum

Pyoderma gangrenosum (PG) is the prototype disease within the neutrophilic dermatoses group. It occurs in association with systemic disorders in about half of the cases and it has been described as part of some autoinflammatory syndromes. The etiology of PG is not well understood. There is not enough supported evidence that the pathogenesis is one of a strictly dysfunctional immune pathway. Some researchers are trying to elucidate molecular pathways by studying tumor necrosis-alpha inhibitors or genetic defects that affect the inflammasome. However, it is still not clear what factor or factors trigger the inflammatory cascade that leads to PG. It appears to be different complex pathways that end up causing the imbalance of the innate response in PG./The purpose of this chapter is to present a comprehensive review of the most recent research on the etiopathogenesis of PG. Having a better understanding of the pathophysiology of PG might help to clarify the different phenotypes of PG as well as to improve diagnosis and management.