Laptop induced erythema ab igne.

Erythema ab igne is a reticular, pigmented dermatosis caused by prolonged and repeated exposure to infrared radiation that is insufficient to produce a burn. The use of laptop computers has increased manifold in the recent past. Prolonged contact of the laptop with the skin can lead to the development of erythema ab igne. We present a case of erythema ab igne secondary to laptop use in an Indian student.

Introduction

Erythema ab igne is a reticular, telangiectatic, pigmented dermatosis which occurs following prolonged and repeated exposure to infrared radiation that is insufficient to produce a burn. It is frequently encountered in cold climates where people use various devices for heating purposes.[1] The use of laptop computers has increased manifold in India with the availability of these at affordable prices. Laptop computers are often placed in contact with the skin during use, thus exposing the skin to prolonged heat. An extensive PubMed search did not reveal any report of laptop-induced erythema ab igne from the Indian subcontinent, although seven cases have been reported in the English literature.[2-5]

Case Report

A 20-year-old male engineering student presented with asymptomatic pigmentation on one side of the abdomen which he had noticed 4 days earlier. There was no preceding history of skin lesions and no similar lesions elsewhere on the body. Further enquiry revealed that the patient had the habit of placing the laptop computer on the bare skin of his abdomen, and he had been using the laptop for at least for 2 to 3 hours per day for the last 2 years. On examination, a diffuse reticular brownish hyperpigmentation was observed on the affected site [Figure 1]. Based on the history and clinical findings a diagnosis of erythema ab igne secondary to laptop use was made. The patient was reassured and advised to avoid placing the laptop in contact with the body.

Figure 1

Erythema ab igne on the abdomen

Discussion

Erythema ab igne—also termed as toasted skin, ephelis ignealis, erythema a calore, and ephelis ab igne—is a reticular, telangiectatic, pigmented dermatosis caused by prolonged and repeated exposure to infrared radiation that is insufficient to produce a burn. It is commonly encountered in cold climates where people use various heating devices.[1]

In western countries, erythema ab igne was initially described as occurring on the shins of those who work or huddle close to a stove or open fire. But with the widespread use of centralized climate control in most buildings these days, the occurrence of erythema ab igne in this location decreased.

The pattern of erythema ab igne depends on the direction of the radiation and the contour of the skin. It begins as mild localized erythema that is often not noticed by the patient. Prolonged and repeated exposures to the heat source result in reticulate erythema, hyperpigmentation, telangiectasia, scaling, and atrophy. The development of subepidermal bullae has also been reported. Erythema ab igne has been reported following the use of various heat sources, including hot pads and electric blankets, open fires, hot stoves, chulha, space heaters, infrared lamps, steam radiators, car heaters, wood-burning stoves, furniture with inbuilt heating unit, heating blankets, frequent bathing in hot water, and sauna belts.[2] To date, only seven cases of laptop induced erythema ab igne have been reported.[3-5]

Cirrhosis, malnutrition, hypothyroidism, internal malignancy, Hansen disease, and anemia are some of the medical conditions that have been associated with erythema ab igne.

The histopathology of erythema ab igne is nonspecific and may appear normal on hematoxylin and eosin stain or may show mild acanthosis and hyperpigmentation of the basal keratinocytes. Biopsy in the early stages may show epidermal atrophy, effacement of rete ridges and pigment incontinence. Occasionally, an interface dermatitis-like picture may be seen. Dilatation and congestion of postcapillary venules and a variable perivascular infiltrate of mild to moderate intensity, consisting of lymphocytes, plasma cells, histiocytes, melanophages, mast cells, and neutrophils may be seen in the dermis. Increased amounts of elastic tissue and hyaluronic acid have been demonstrated with special stains.[6]

Rare instances of bullous erythema ab igne, cutaneous horn with thermal keratosis, squamous cell carcinoma and Merkel cell carcinoma arising in erythema ab igne lesions have reported.[78]

The various treatment modalities suggested for erythema ab igne include topical retinoids, with or without topical steroids and 5-fluorouracil cream.

Biopsy for histopathology was not done in our patient as the findings in such cases are usually nonspecific.

The information technology revolution and the availability of laptops at affordable prices has resulted in widespread use of laptops by the younger generation. A history of laptop use must be enquired for on diagnosing a case of erythema ab igne, especially when it occurs on the thighs and abdomen among the youth and those involved in the IT field.