Why You Should Not Use Laptop Directly On Your Lap

Erythema ab igne is a medical term for a condition in which there is redness in the skin of the thigh and nearby areas due to low-grade heat exposure. This article primarily deals in the heat dissipation from the laptop onto our thighs if the laptop is placed and used for a prolonged duration there.

History of Erythema Ab Igne

Historically, this skin reddening due to close contact with heat waves was common among blacksmiths and silversmiths, as their work required such hot conditions and nearly constant exposure. With the advent of using natural gas for cooking, cooks working close to the heated stoves started experiencing red lesion formation on their skin. Finally, with the invention of transistors and microprocessors, computers were quickly taken up by the masses. Desktop computers were used with great fervor, but they kept people locked to the place where the computers were kept. People needed to use computers for the modern era, but had almost no mobility.


Blacksmiths and silversmiths used to be the profession who suffered from erythema ab igne. (Image Credit: Pixabay)

Toasted Skin Syndrome

With a mission to impart portability and on-the-go mobility, laptops were invented. However, the incessant usage of a laptop kept directly on one’s lap for hours exposed our thighs to electromagnetic radiation and heat waves. This resulted in many skin problems, with a typical one being discolored or patchy skin.

While your eyes and mind are chained to the laptop, it’s your thighs that face the heat if you keep your laptop resting directly on your thighs for hours at a time. This results in what is colloquially called Toasted Skin syndrome—evidenced by red patches on the thighs. People often don’t make the connection between the rash to heat exposure. Only when these rashes become conspicuous or painful do people start to realize that their laptop usage is causing this trouble. In fact, prolonged thermal radiation exposure to the skin from those laptop vents can lead to the development of various medical complications, such as reticulated erythema, hyperpigmentation, scaling and telangiectasias.

Causes and Impacts

The pathogenesis of erythema ab igne still remains fairly unknown, despite researcher’s increased attention to the problem in recent years. The good thing is that there is unanimity amongst medicinal practitioners and experts that prolonged thermal radiation from laptops used directly on the lap induces epidermal damage to superficial blood vessels, which can lead to vascular dilation. To put this simply, vascular dilation is the abnormal enlarging of blood vessels. It has also been observed that the distribution of the affected blood vessels predominantly lies in the superficial subcutaneous plexus (medical term for the branching of blood vessels under the skin), resulting in the net-like pattern of erythema ab igne skin lesions.

Dell Mini 12 bottom

Air vents in laptops are often located on the bottom, which is in contact with the thighs if the laptop is used directly on one’s lap. (Photo Credit : Pittaya Sroilong/Wikimedia Commons)

The prolonged placement of a laptop on your thighs results in a temperature build-up of 43-47oC, depending on the type of processor and the size of the laptop’s vent. In fact, laptops with powerful processors can raise that temperature as high as 50oC, which can be very detrimental to the skin. Due to stagnation of the blood (medically called local hemostasis) when exposed to high-temperature heat waves, the skin develops a patch that is often mottled and later becomes reticulated erythema, leaving behind the signs in the form of pigmentation. This coarsely reticulated pigmentation produced by exposure to laptop heat vents may occur without the generation of any burns.

Treatment and Cure

The first step to treating erythema ab igne is to identify the root cause, i.e., prolonged laptop usage. Dermatologists, i.e., doctors who deal with skin problems, opine that the mild skin change—if detected early—can heal on its own without treatment. For more persistent redness, dermatologists might recommend anti-inflammatory cream to be used topically on the affected region. However, they do caution on one thing: repeated skin exposure can lead to tissue wastage due to the degeneration of cells. Experts believe that if persistent soreness occurs, a skin biopsy should be performed to rule out the possibility of skin cancer. For all other cases, a topical tretinoin (a drug related to vitamin A or retinol) cream may be prescribed. In more critical cases, a person might need to undergo laser therapy.

laptop computer people technology internet notebook business

Using a laptop on a table/stand/cooling pad is the medically most recommended way of using a laptop in order to prevent erythema ab igne. (Image Credit: pixnio)

Prevention is better than treatment is the golden adage in medicine, and the same applies to the modern electronic world. Using a laptop table/cooler, rather than directly placing your laptop on the thighs, can help to avoid most of the skin issues caused through heat being dissipated by vents from the laptop.


  1. Sciencedirect
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About the Author:

Hussain Kanchwala is an Electronic Engineer from University of Mumbai. He is a tech aficionado who loves to explicate on wide range of subjects from applied and interdisciplinary sciences like Engineering, Technology, FinTech, Pharmacy, Psychology and Economics.

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