Pyoderma gangrenosum and erosive peripheral arthritis

Area of Science:

• Rheumatology
• Dermatology
• Immunology

Background:

• Pyoderma gangrenosum (PG) is a rare, neutrophilic dermatosis.
• Peripheral erosive arthritis is uncommon in PG.
• Psoriatic arthritis (PsA) commonly presents with peripheral erosive arthritis.

Observation:

• Two patients with biopsy-proven pyoderma gangrenosum presented with peripheral erosive arthritis.
• The arthritis in these patients resembled the peripheral erosive pattern typically seen in psoriatic arthritis.
• This presentation is unusual for pyoderma gangrenosum.

Findings:

• The co-occurrence of biopsy-proven pyoderma gangrenosum and peripheral erosive arthritis suggests a potential association.
• The arthritis's resemblance to psoriatic arthritis raises questions about shared underlying mechanisms or a distinct subtype of arthritis in PG.
• The findings prompt consideration of reactive arthritis as a possible link or differential diagnosis.

Implications:

• This case series highlights a potential, previously under-recognized association between pyoderma gangrenosum and peripheral erosive arthritis.
• Further research is needed to elucidate the pathogenesis of this arthritis in PG patients.
• Considering reactive arthritis in the differential diagnosis for patients with PG and arthritis may improve patient management.