Narrative Review: Pyoderma Gangrenosum

Pyoderma gangrenosum (PG) is a skin lesion, characteristically a neutrophilic dermatosis, that can be complicated by rapid progression, necrosis, and ulceration. This is an important pathology to be discussed given that there are no established criteria for diagnosis or treatment. This review aims to elucidate characteristics and variations of PG that distinguish it from other ulcerative skin lesions. Variability in presentation can lead to missed or incorrect diagnosis, and some of the currently proposed criteria for categorizing and diagnosing PG have been included here. These criteria distinguish PG in terms of the nature of the lesion, the location, etiology, responsiveness to immunosuppressive therapy, and patient history. The etiology and pathogenesis of PG remain unknown, but we summarize prominent theories and explanations. Furthermore, recent research indicates that the incidence of PG has a strong correlation with autoimmune conditions, particularly inflammatory bowel disease. Major treatments for PG coincide with these findings, as the majority involve targeted anti-inflammatories, immunosuppressants, and surgical interventions. These treatments are addressed in this review, with added context for local versus systemic disease.