Boy's Mysterious Skin Condition Traced Back to Laptop Use

Doctors in the U.K. traced a mysterious honeycomb-patterned rash on a boy's stomach to hours of laptop use, in a case reported in BMJ Case Reports. The child was brought to the emergency department at University Hospitals of Leicester with what nursing staff initially suspected was ordinary bruising from rough play with a sibling.

Scans showed no internal trauma, and doctors ruled out other explanations such as livedo reticularis, a mottled skin pattern caused by cold exposure. The boy was prescribed a course of antibiotics and sent home to rest. Weeks later, he returned with the fishnet-like marks darker and more tender, now accompanied by a pink, tender rash.

Doctors then considered erythema ab igne, also known as toasted skin syndrome, a condition caused by prolonged exposure to mild heat that damages blood vessels near the surface of the skin. At first, the boy's parents could not think of a heat source strong enough to cause it — there was no hot water bottle or space heater involved. The cause turned out to be a laptop the boy had been balancing on his abdomen, often while it was charging, for up to eight hours a day.

Erythema ab igne from laptop use is not uncommon in young adults, particularly students, but the condition is not something doctors typically consider when diagnosing children, according to the case report's authors, general practitioner Mara Znagoveanu and paediatrician Edward Artley. The condition is not usually dangerous, and any skin color changes resolve once the heat source is removed, though rare cases have involved pre-cancerous cell changes, including one severe case that triggered a squamous cell carcinoma. A follow-up phone call with the boy's father several months later confirmed the rash had disappeared.

"Early recognition through targeted history-taking can prevent misdiagnosis and avoid unnecessary investigations," the authors concluded, noting the importance of considering the condition when doctors encounter similar fishnet-pattern bruising or rashes in a child.