A 10-month-old child presented with an ulcerated lesion on his right arm. The lesion was caused by arginine monohydrochloride extravasation during growth hormone testing, performed 2 months before. On physical examination, there was a 3 cm x 4 cm oval sore, with a thick fibrous base and turgid, violaceous, raised edges on the dorsal aspect of the child's right hand and wrist. Conservative management with local medications led to complete resolution within 2 months.