AbstractWe report details of a diabetic patient who developed pyoderma gangrenosum following cholecystectomy, and subsequently developed ulceration of the thumb at the site of finger‐prick for capillary glucose monitoring. Although the latter was thought to be due to viral infection, pyoderma gangrenosum may also have been involved as it is associated with impaired immunological function and abnormal cutaneous response to minor trauma. The possible relationship between pyoderma gangrenosum and diabetes is discussed, and also the implications for therapy of the two disorders. The pyoderma gangrenosum resolved with steroid therapy.