Neutrophilic dermatoses - Pathomechanistic concepts and therapeutic developments

Neutrophilic dermatoses are a group of clinically heterogeneous diseases characterized by infiltration of neutrophils in the affected tissue. Skin symptoms comprise a spectrum of wheals, papules, plaques, pustules, nodules and ulcerations often in combination with systemic symptoms. Although the pathogenesis of these diseases has not yet been elucidated in depth, broad pathophysiological and clinical overlaps exist with autoinflammatory syndromes. Additionally, recent years have shown the relevance of the signaling pathways of TNF-α, IL-1, IL-12/23 and IL-17 in neutrophilic dermatoses. In this review, we present four selected neutrophilic dermatoses, namely pyoderma gangraenosum, Sweet syndrome, generalized pustular psoriasis and Schnitzler syndrome, discuss pathophysiological aspects and specifically address novel therapeutic options derived from the most recent pathophysiological findings.