My uncle who is 72+ had a rash in his leg ankle 2 months back , which on scratching turned into a wound. He is taking medication for diabetes and hypertension. During this incident, his diabetes was very high(around 300+) . He referred a few diabetologists and endocrinologists. The blood sugar was brought down with medications and diet, but the wound and pain still persisted. A scan as per prescribed for tissue infection was also done and found to be ok.  One of the doctors recently mentioned that it could be vasculitis and is suggesting for a biopsy. Can someone please advise if that could be the case? Attaching the leg's pic .