Pyoderma gangrenosum or necrotising fasciitis? Diagnostic and therapeutic wanderings

A case of post-traumatic lower-limb pyoderma gangrenosum (PG) in a 77-year-old female is reported. The diagnosis of PG is frequently one of exclusion, and it is therefore unsurprising that the condition was initially mistaken for necrotising fasciitis then for necrotising bacterial dermo-hypodermitis. Medical and surgical treatment for those conditions proved ineffective. This fact, together with the atypical presentation, promoted a re-evaluation of the diagnosis. The clinical findings and investigation results converged to suggest PG, and a therapeutic trial was initiated. The good treatment response and negative findings from tests for other conditions established the diagnosis of post-traumatic PG.