system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
A 14-year-old boy is brought to the physician by his parents for the evaluation of a skin rash for one day. The patient reports intense itching. He was born at 39 weeks' gestation and has a history of atopic dermatitis. He attends junior high school and went on a camping trip with his school the day before yesterday. His older brother has celiac disease. Examination shows erythematous papules and vesicles that are arranged in a linear pattern on the right forearm. Laboratory studies are within normal limits. Which of the following is the most likely underlying cause of this patient's symptoms?
assistant
Presensitized T cells