The FP noted the deep ulcers with gun-metal (violet blue coloration) undermined borders. The edge of the upper left corner of the suprapubic ulcer also had a cribriform pattern (pierced with holes like swiss cheese). The FP’s differential diagnosis included pyoderma gangrenosum (PG) and a deep fungal infection.
The FP was aware that it could take months before the patient could be seen be a dermatologist, so he offered to perform a 4-mm punch biopsy at the edge of the ulcer. (Note that the correct location for a biopsy of an ulcer is on the edge, not in the middle). (See the Watch & Learn video on “Punch biopsy.”)
The pathologist found a dense neutrophilic infiltrate and stated that this supported the diagnosis of PG. No fungal elements were seen with a Periodic acid–Schiff (PAS) stain. PG is a rare neutrophilic dermatosis, without a known cause, that is sometimes seen with inflammatory bowel disease.
The FP called a local dermatologist, and they decided to start the patient on oral prednisone until she could be seen in the dermatologist’s office. The dermatologist stated that she would be considering oral cyclosporine, oral dapsone, or injectable biologic agents as steroid sparing agents to treat the PG.
Photos and text for Photo Rounds Friday courtesy of Richard P. Usatine, MD. This case was adapted from: Mayeaux, EJ, Usatine R. Pyoderma gangrenosum. In: Usatine R, Smith M, Mayeaux EJ, et al. Color Atlas and Synopsis of Family Medicine. 3rd Ed. New York, NY: McGraw-Hill; 2019:1147-1152.
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