Blisters on palms and soles

Clinical case

A 32-year-old man presents with palmoplantar blisters that caused considerable itch and discomfort (Figures 1, 2). The eruption started as small vesicles on the sides of the digits and rapidly extended to the rest of the palms and soles, coalescing into larger blisters.

He has no history of dermatitis or allergies and is experiencing this eruption for the first time. He is otherwise well and not on any regular medications. What is the most likely diagnosis?