A 3-Year-Old with Lesions on His Thumb

A mother brings her 3-year-old son to urgent care with multiple skin lesions on his thumb, which he frequently sucked for comfort. The grouped configuration of lesions was painful and had developed over the last 5 days to become vesicles.

Upon exam, you note that the boy has a nearly healed cold sore on his lip, pain in his wrist, and an elevated temperature.

View the photo and consider what your diagnosis and next steps would be. Resolution of the case is described on the next page.