A strange honeycomb rash appeared on a child’s stomach and grew more painful over weeks, until doctors traced the unusual skin damage to how he used his laptop

A mysterious rash on a child’s abdomen initially looked like bruising from an injury. But when the marks became more tender and began affecting the skin, doctors had to reconsider what was causing them.

The unusual case, reported by doctors from University Hospitals of Leicester in BMJ Case Reports on September 8, involved a pre-teen boy who was otherwise well. According to the case report by Mara Znagoveanu and Edward Artley, the child presented with a reticulated, or net-like, rash on his abdomen that had initially been thought to be related to trauma.

The boy had told clinicians that he had recently been play-fighting with his sibling and had been pushed into a chair. That history made an injury seem plausible. But investigations did not support serious internal trauma: blood tests and abdominal imaging were unremarkable, according to the published report. Then the skin changed.


When the child returned roughly two weeks later, the rash had progressed. It had become more tender and developed areas where the surface skin was breaking down. This prompted doctors to look beyond ordinary bruising and consider a condition that can produce a distinctive lace-like pattern.

The diagnosis was erythema ab igne, sometimes known as “toasted skin syndrome”.

The clue was hiding in his daily routine

Erythema ab igne develops when skin is repeatedly exposed to relatively low levels of heat over a prolonged period, heat that is not necessarily intense enough to cause a conventional burn. The repeated exposure can produce a reddish, brownish or hyperpigmented pattern resembling a net or fishnet.

The condition was once more commonly associated with traditional heat sources such as fireplaces, heating pads and hot-water bottles. But electronic devices have become another source of prolonged localised heat.

In this case, further questioning revealed the crucial detail: the boy was being home-schooled and regularly rested his laptop directly against his abdomen for educational work, sometimes for up to eight hours a day. The laptop was also frequently used while charging, according to the BMJ report.

That history connected the unusual rash with repeated low-grade heat from the computer.

The doctors advised him to stop placing the laptop directly against his body. Several months later, his father reported during a telephone follow-up that the rash had gradually disappeared.

What is “toasted skin syndrome” and how can it be avoided?

Erythema ab igne is a heat-induced skin condition, rather than an infection or conventional bruise. According to dermatology reference DermNet, prolonged exposure to a heat source can initially cause a mottled red or brown discoloration that develops into a more pronounced reticulated pattern.

The simplest way to prevent it is to remove the source of repeated heat before prolonged skin changes develop. That means avoiding direct, extended contact between bare skin and heated laptops, heating pads, hot-water bottles or other warm objects.

For laptop users, placing the computer on a desk, table or other hard surface rather than directly on the thighs or abdomen can reduce prolonged heat exposure. Users should also avoid keeping a warm device pressed against the same area of skin for hours.

Most cases improve after the heat source is removed, although discoloration can sometimes persist. DermNet notes that longstanding erythema ab igne has rarely been associated with skin cancers, including squamous cell carcinoma.

It is unusual, but not unprecedented

This Leicester case is not the first report of laptop-related erythema ab igne in a child. A 2010 Pediatrics case report described a 12-year-old boy who developed the condition on his thigh after prolonged laptop use. Researchers noted that heat could come from components including the computer's battery, optical drive or ventilation system.

The newer Leicester report is significant because the presentation could initially be mistaken for injury or another medical condition, potentially leading to investigations that are unnecessary once the source of heat is recognised. The authors say clinicians should specifically ask about prolonged contact with electronic devices when children develop reticulated skin changes.