Systemic associations of pyoderma gangrenosum: a systematic review.

BACKGROUND

Pyoderma gangrenosum (PG) is a rare neutrophilic dermatosis that may be associated with systemic diseases. Characterizing these associations is clinically relevant for diagnosis, prognosis and management.

OBJECTIVES

To systematically review acquired systemic diseases associated with PG in adults and describe related clinical features and treatment approaches.

METHODS

We searched PubMed/MEDLINE, Embase and Scopus from January 2015 to May 2025. Eligible studies included observational studies, case reports and case series reporting systemic associations of PG in adults. Data extraction was performed independently by two reviewers and the risk of bias was assessed using the Joanna Briggs Institute checklists.

RESULTS

Nineteen observational studies and 18 case-based studies were included. The most frequent systemic associations were inflammatory bowel disease (n = 13), haematological disorders (n = 6), solid organ malignancy (n = 3) and arthritis (n = 3). Less common associations included vasculitides, autoimmune conditions, connective tissue diseases and organ--specific disorders. In the observational literature, only three studies reported PG subtypes, with the ulcerative form accounting for more than 85% of cases. Case-based literature highlighted patterns such as relapse-prone disease in patients with vasculitis and therapeutic responses to biologics in refractory cases.

CONCLUSIONS

PG demonstrates diverse systemic associations, ranging from well-established links to rarer conditions. Observational studies strengthen evidence for common associations, while case-based literature provides insights into clinical patterns and emerging therapies. Larger prospective studies are needed to clarify causality and optimize management.