Poor prognosis of arthritis-associated pyoderma gangrenosum.

Background: The association between pyoderma gangrenosum (PG) and arthritis is well established. We have observed a refractory population of patients with arthritis-associated PG (PGA). We, therefore, tested the hypothesis that differences exist in response to treatment in patients with PGA compared with patients with PG without arthritis.
Observations: We performed a review of patients with PG during a 2-year period. Patients had noninfectious chronic ulcerations clinically typical for PG, exclusion of relevant differential diagnoses, and consistent histopathological features. Outcomes compared between patients with arthritis (PGA) and without arthritis (PG) included complete healing, percentage change in wound size, and duration of therapy. Of 10 PG ulcers, 7 healed, compared with 2 of 8 PGA ulcers. There was a greater mean percentage decrease in wound size in the PG vs the PGA ulcers (78.9% vs 23.4%; P =.10) and a shorter mean duration of treatment (8.7 vs 14.8 months; P =.18).
Conclusions: The ulcers of patients with PGA seem more refractory to treatment than the ulcers of patients with PG alone. Those with PGA ulcers represent a refractory subset of patients, and the ulcers are possibly secondary to unique pathophysiological features.