A 37-year-old man presents to an outpatient clinic for evaluation of pruritus and skin lesions. The symptoms developed five weeks ago and have progressively worsened. The symptoms are diffuse but most prominent in the upper extremities
. The patient frequently wakes up at night due to itching and has difficulty falling asleep again. Past medical history is notable for inflammatory bowel disease
. The patient worked as a fisherman but lost his job a year ago. Since then, he has been residing in a homeless shelter. His temperature is 37.2˚C (99.0˚F), pulse
is 92/min, and blood pressure
is 147/85 mmHg. The heart and lungs are clear to auscultation
. Abdominal examination is unremarkable. Examination of the patient’s hands is shown below. Which of the following best describes the pathophysiology of this patient’s condition?
Image reproduced from Wikimedia Commons