Rare, painful, recalcitrant ulcer
Pyoderma gangrenosum is a chronic ulcerating dermatosis that appears to be immune-mediated.1
It is characterised by the sudden onset of a purplish red plaque, which enlarges and then breaks down into a painful skin ulcer with undermined borders.
Pyoderma gangrenosum, often triggered by trauma termed ‘pathergy', typically occurs on the lower limbs but may occur at other sites. The aetiology is uncertain, but more than 50% of cases are associated with underlying inflammatory disease.2
There are four broadly recognised