A 60-year-old Hispanic man with a history of insulin-dependent type 2 diabetes mellitus presented with tender nodules on his right forearm. The symptoms had begun 4 months earlier, when the patient first noted a small red lump on his right arm. Over time, he developed multiple nodules on the same arm and became concerned when the lesions began to drain clear fluid. He admitted to self-administering insulin injections on the right arm in the area of the lesions, but could not recall sustaining any other trauma to the area. Also, he denied gardening, owning a fish tank, and handling fish or meats.