Review Question - QID 213770

A 51-year-old man presents to his primary care physician with a 1 week history of a rash. On presentation, he says that he noticed a rash on his knees after he was pulling weeds in the garden. He is worried that he may have accidentally come into contact with some sort of poisonous plant. He says that the lesions are very pruritic and have remained relatively constant over time. Physical exam reveals the lesions seen in Figure A. Which of the following is associated with this patient's disease?