An unusual ‘bruise’ in the ER

After toilet scrolling and its link to hemorrhoids, here’s another digital habit that can leave unexpected marks. This time, a cellphone wasn’t to blame.An 11-year-old boy arrived at the pediatric emergency department of Leicester Royal Infirmary in central England with what the triage team described as “spontaneous bruising.” The strange mark had appeared on his abdomen a week earlier.Initially, his parents thought it was simply a bruise. In fact, the boy only mentioned it to them when the mark darkened and failed to fade. On examination, the lesion measured approximately 15 cm and covered the upper right quadrant of his abdomen. It was flat, reddish-brown, with no scaling or raised areas. The boy reported neither pain nor itching and was otherwise well. But the lesion’s pattern was puzzling.The two physicians who reported the case in BMJ Case Reports, Dr. Mara Znagoveanu and Dr. Edward Artley, described the lesion as having a "distinct pattern, with interlacing lines forming irregular circles and a lace-like morphology. The borders were ill-defined and faded into the surrounding skin." There were no other skin lesions or bruises, nor any systemic symptoms to help explain the findings. Neither the boy nor his parents knew what could have caused the mysterious mark.Then one detail changed everything. During a blood draw, the young patient finally revealed that a week earlier, while playing with a sibling, he had been pushed against a chair. He had kept quiet about the incident because he was afraid of getting his sibling into trouble.An injury now seemed a more plausible explanation. Blood tests were normal, and an abdominal CT scan showed no intra-abdominal injuries. With no other concerning findings on examination, the boy was sent home.A few weeks later, the boy returned to the emergency department. This time, the lesion had spread and become tender. Within the brownish patch, a pinker area now suggested changes to the skin itself. “These changes prompted a reconsideration of the initial diagnosis of bruising,” the authors wrote.Digging deeperThe physicians revisited the patient’s medical history. At first, conversations with the boy and his parents revealed nothing. They needed to dig deeper.As they explored his daily routines more closely, one important detail finally emerged: The boy was homeschooled and spent long periods using a laptop for his schoolwork. More importantly, he rested it directly on his abdomen for up to eight hours a day, often while it was charging, the physicians reported.Suddenly, the clinical picture made sense.The authors diagnosed erythema ab igne, a skin condition caused by repeated exposure to a heat source that is not hot enough to cause an acute burn. The treatment was straightforward: Stop placing the laptop directly against the skin. A few months later, the boy’s father confirmed by telephone that the lesion had gradually improved before disappearing completely.This is not the first time laptop computers have been linked to this type of skin lesion. The authors note that laptop-induced erythema ab igne is “well recognized in adults,” although it is reported less frequently in children.A familiar culpritAs early as 2010, Pediatrics described a 12-year-old boy who developed the condition on his left thigh after using a laptop. And a review published in 2023 identified 32 pediatric cases of erythema ab igne associated with various heat sources.What sets the Leicester patient apart is how the problem initially presented. His case was similar to previous reports “in appearance and trigger,” the physicians wrote, but differed in the lesion’s abdominal location and the fact that it was initially mistaken for the aftermath of an injury—a misleading clue that ultimately led to diagnostic imaging.Beyond the unusual circumstances, the authors emphasize a simple lesson: When faced with a reticulated skin lesion, asking about repeated heat exposure is essential. A “targeted history” can help prevent misdiagnosis and unnecessary investigations, they note.As our habits change, so do some of the questions physicians need to ask their patients.This article has been translated from its original French and first appeared on our sister site Profession Santé.

An unusual ‘bruise’ in the ER

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