Dermatology Online Journal

Frictional lichenified dermatosis from prolonged use of a computer mouse: Case report and review of the literature of computer-related dermatoses
Pedram Ghasri BS, Steven R Feldman MD PhD^1,2,3
Dermatology Online Journal 16 (12): 3

Center for Dermatology Research
1. Department of Dermatology
2. Department of Pathology
3. Department of Public Health Sciences
Wake Forest University School of Medicine, Winston-Salem, North Carolina

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Abstract

Despite the increasing reliance on computers and the associated health risks, computer-related dermatoses remain under-represented in the literature. This term collectively refers to four groups of cutaneous pathologies: 1) allergic contact dermatitis from exposure to certain chemicals in computer accessories, 2) various friction-induced hand lesions resulting from prolonged computer use, 3) erythema ab igne from placement of the laptop on the skin, and 4) “screen dermatitis” from excessive exposure to visual display terminals (VDTs). Within this review we also present a case of a friction-induced lichenified dermatosis in the dominant wrist of a 24-year-old female that was caused by excessive use of her computer mouse. More importantly, we review the literature of all previously reported cases of computer-related dermatoses, so as to promote recognition and appropriate management by both patients and physicians.

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Introduction

Whether in the workplace, classroom, or home, the computer is an integral part of our everyday lives. However, as computer use becomes more ubiquitous, associated health problems are rising and becoming more recognized. Musculoskeletal pain, visual disturbances, headaches, and psychosocial stress are widely recognized computer-related health concerns [1]. Dermatological complaints however, appear to be under-reported in the literature, with only a limited number of cases previously reported [2-13].

Clinical cases of computer-related dermatoses can primarily be categorized into one of four groups of cutaneous pathologies: 1) contact dermatitis from exposure to certain chemicals in computer mice, keyboards, and wristpads, 2) various friction-induced lesions on the hand resulting from over-use, 3) erythema ab igne resulting from prolonged placement of the laptop and its associated heat source directly on the skin, and 4) “screen dermatitis” from excessive exposure to visual display terminals (VDTs). Herein we describe a case of a friction-induced lichenified dermatosis in the wrist of a 24-year-old female caused by excessive use of her mouse. This case presents an opportunity to review the literature of all previously reported cases of computer-related dermatoses, with the aim of fostering familiarity of their various etiologies and manifestations.

Case presentation

Figure 1	Figure 2
Figure 1. Contact of the ulnar aspect of the patient’s right wrist with the desk when using the mouse Figure 2. A 3 x 3 cm, dark, hyperkeratotic thickening on the ulnar aspect of the patient’s right wrist

A 24-year-old healthy Caucasian female presented with an asymptomatic eruption on her right wrist of 2 months’ duration. She was a former hospital cafeteria employee who recently quit her job in order to stay home and raise her 5-year-old daughter. She reports that she had spent approximately 12 hours a day on her computer over the past four months, mostly browsing popular social networking internet sites. Prior to that, she reported spending 3-4 hours per day on the computer over the past 10 years. The patient reported that she uses her mouse in such a way that the affected part of her wrist continuously rubs the edge of the desk (Figure 1). On clinical examination, there was a 3 x 3 cm, dark, hyperkeratotic, slightly verrucous plaque on the ulnar aspect of her right wrist (Figure 2). The patient was reassured of the benign nature of the lesion and was informed that it was likely induced by extensive frictional contact between her hand and the desk.

Discussion

Here we report the case of 24-year-old female who developed an asymptomatic, hyperpigmented, lichenified dermatosis in the ulnar aspect of her wrist after continuous, prolonged use of her computer. The patient used the computer mouse with her right hand in a manner in which the affected area repeatedly rubbed against the edge of the table. Seemingly, the continual frictional contact between her hand and the table led to the formation of the lichenified plaque. Similar clinical presentations of asymptomatic, hyperpigmented lesions caused by chronic friction have been reported in a variety of settings outside of the realm of computers. For instance, violin and cello players may develop “fiddler’s neck” and “cello knee” from prolonged contact of the instruments with their neck and knees, respectively [14]. “Prayer marks” are interesting signs that develop in devout religious observers as a result of continuous pressure over bony prominences during prayer ceremonies [15]. The development of these lichenified lesions in a variety of settings is seemingly a physiological protective response to friction, characterized by an increased rate of turnover in epidermal cells and accumulation of thickened collagen bundles the papillary dermis [16].

Upon review of the literature, we identified 22 prior cases of patients who developed a dermatosis from prolonged use of their computer (Table 1). Seven cases were diagnosed as allergic contact dermatitis; the lesions were uniformly characterized by pruritic, scaly, erythematous, vesicular patches and plaques on areas of the palmar aspect of the hand in direct contact with the mouse, mouse pad, or mouse wrist pad. Nine cases can be categorized as friction-induced dermatoses, which include clinical variants that are analogous to pressure ulcers, callouses, and irritant dermatitis. Lastly, seven cases of erythema ab igne were reported, which were all induced by prolonged placement of the patient’s laptops on their anterior thighs

Contact Dermatitis

The computer mouse has been implicated in three reported cases of allergic contact dermatitis. Capon et al. first described two cases of young women who developed erythematous, vesicular lesions on the palms of their dominant hands [2]. The diagnosing physicians astutely recognized that both patients had substantial contact with computers in the home and office and subsequently performed patch testing. The results ultimately revealed sensitivity to diethyl phthalate and dimethyl phthalate, chemicals that were present in the plastics of their computer mice. The patients were instructed to use a cover over the mouse and their lesions subsequently subsided. Phthalates are additives that are commonly used to create flexible plastics, such as those found in chewing toys and wrist bands, so the occurrence of the contact dermatitis to the stiff plastic found in the computer mouse was quite surprising [17]. It is plausible that the prolonged contact with the mouse and the subsequent sweating and frictional contact likely lowered the sensitization threshold.

Goossens et al. similarly reported a case of a female secretary who presented with allergic contact dermatitis to resorcinol monobenzoate, a UV absorber added as a stabilizer to plastics to prevent damage from sunlight [3]. Previous case reports have associated this additive with contact dermatitis from eye-glass frames and hearing aids, both of which are worn for prolonged periods of time [18]. It is plausible then that the reaction to the resocrcinol monobenzoate was likewise perpetuated by prolonged frictional contact and sweating in the patient’s hands.

The mouse pad has also been implicated as the cause of contact dermatitis. Garcia-Morales et al. reported a sharply demarcated eruption characterized by erythema, vesiculation, and scaling on the palmar aspect of the right thumb of an office worker who used his computer for 6 hours per day [5]. The patient was diagnosed as having allergic contact dermatitis after he was found to have positive patch testing to chemical components in the neoprene rubber of the mouse pad, and his lesions subsequently improved after 7 days of disuse.

In addition to eczematous reactions from the mouse and the mouse pad, there are also 3 prior reports of allergic contact dermatitis to allergens found in the keyboard wrist rest pad. Johnson et al. reported the case of a woman with a previously diagnosed allergy to mercapto and thiuram mixes, who developed a vesicular and bullous dermatitis on the palmar aspects of her wrists and erythematous, scaly lesions on her arms, legs, and face [7]. One week prior to her presentation, she had purchased a wrist pad made of neoprene rubber, which contained thiurams and mercaptans. A diagnosis of allergic contact dermatitis was made and the patient’s symptoms gradually resolved with a prednisone taper. Two other young women were reported who developed erythematous, hyperkeratotic lesions on the areas of their palms that were in contact with their keyboard wrist rest pad [8, 9]. Both had positive patch testing to dialkyl thiourea found in the rubber component of the rest pads.

Friction-induced dermatoses

Inclusive of our patient, there are nine cases of non-inflammatory computer-related dermatoses, which are all collectively caused by prolonged pressure and friction. Lewis et al. reported two cases of computer programmers who had a 20-year extensive history of computer use for at least 10 hours per day [10]. Both patients presented with asymptomatic well-demarcated erythematous, blanchable patches with telangiectasias on the ulnar aspects of their palms bilaterally. They had a habit of leaning forward and resting their palms on their keyboard and desk to alleviate back pain from sitting. The authors termed the lesions “computer palms” and likened them to a Stage 1 pressure ulcer, which was formed from reactive vessel engorgement and hemorrhage caused by long-term pressure induced ischemia.

Tanaka et al. reported two cases of similar lesions on the ulnar side of the wrist, a clinical entity they coined as “keyboard wrist pad.”[11] Both patients were office workers who had a 10-20 year history of computer use for 6 hours per day. They presented with asymptomatic, well-circumscribed hyperkeratotic plaques. The authors attributed the formation of the lesions to prolonged frictional contact with the desk when the patients used the keyboard, and recommended soft cushion pads to resolve the lesions. Goksugur et al. recently reported an asymptomatic, yellowish, hyperkeratotic lesion on the palmar side of the dominant hand of an academician who had a 3-year history of computer use for at least 10 hours a day [13]. The authors recognized the lesion as having been caused by recurrent friction between the wrist and the table from chronic use of the mouse, a diagnosis they termed “mousing callus.” Based on the history and physical appearance of the plaque, this presentation most closely resembles that of our patient.

Another patient with a history of severe allergic contact dermatitis to chemicals found in industrial products developed an erythematous, scaly, vesicular dermatitis on her right palm after using her computer mouse 6 hours per day for 2 months [4]. After negative patch testing to the chemicals found in the mouse, the patient was diagnosed as having irritant contact dermatitis that was caused by prolonged pressure, friction, and sweating. Vermeer et al. recently reported a variant of irritant contact dermatitis on the first and fifth fingertips of the right hand of a 32-year-old computer programmer who spent 4 hours per day on the computer for 5 years [6]. They aptly termed the reaction “mouse fingers,” and as with the other eczematous reactions reported to computer mice, they suggested that the symptoms were caused by repetitive friction and pressure between the fingers and the mouse pad.

In addition to isolated case reports of computer-related dermatoses, there exists one small clinical study involving 150 mouse users [12]. As Dermatology Ph.D. candidates who themselves developed callous-like lesions from excessive computer use, the investigators were interested in observing the prevalence of similar lesions. They found that 54% of the surveyed subjects had developed a well-demarcated, yellow-red, lichenified plaque on the ulnar side of the wrist of the dominant hand that they used to control the mouse. They observed that the severity of the lesion was proportional to the average time of computer use per week and suggested that the lesions developed in response to prolonged friction, pressure, and shearing between the wrist and the mouse pad.

Erythema Ab Igne

Erythema ab igne is characterized by localized areas of reticular erythematous hyperpigmenation. This rare dermatosis results from excessive skin exposure to mild heat that is in a range insufficient to produce a thermal burn. Typically, patients provide a history of prolonged exposure to traditional heat sources such as open fires, space heaters, heating pads, wood stoves, or hot water bottles. Several cases of non-traditional heat sources have also been implicated as a cause of erythema ab igne, including laser hair removal, hot popcorn, car heaters, and frequent hot bathing. Most recently, erythema ab igne has developed from exposure to laptop computers, with seven cases reported in the literature. In all of the cases, the asymptomatic reticular hyperpigmented patches developed on the anterior thighs, at the site of prolonged direct exposure to the heating source of the laptops. The patients were between the ages of 17-50 and the majority of them provided a history of placement of their laptop on their laps for a prolonged period of time. All of the diagnoses were made from clinical examination and the lesions resolved within months after the patients refrained from placing their laptops directly on their legs.

Screen dermatitis

Another computer-related dermatosis that is well-represented in the literature, unlike the contact and frictional dermatoses, is “screen dermatitis.” As a reaction to chronic exposure to visual display terminals (VDTs) from computer monitor screens, patients develop a rosacea-like dermatitis characterized by heat, pruritis, pain, papules, erythema, and pustules [19]. The precise underlying etiology of this constellation of symptoms remains unclear and has been a topic of much investigation. Berg et al. demonstrated that the majority of these patients had a predisposed sensitive skin, he observed “screen-dermatitis”-like lesions when he applied 5 percent lactic acid and pure water on their cheeks [20]. Gangi and Johansson sought to explore the molecular causes of “screen dermatitis.” They demonstrated that the clinical manifestations and histochemical changes were strikingly similar to skin damage from UV light and ionizing radiation. More specifically, they observed alterations in cell populations, namely an increase in mast cells and decrease in Langerhan cells [21]. In accordance with these studies, conclusions drawn from a case study of 149 office workers proposed that the dermatitis was caused by non-specific irritant factors in people who had sensitive skin as well as psychosocial stressors [22].

Conclusion

Computer-related health problems are increasingly being recognized and chronic users are at risk of developing musculoskeletal disorders, visual disturbances, headaches, and dermatological problems. Four categories of computer-related dermatoses are recognized in the literature—contact dermatitis, friction-induced lesions, erythema ab igne, and screen dermatitis. Physicians and patients should be aware of the various computer-related dermatoses so that they can be readily recognized and managed accordingly.

References

1. Sen A, Richardson S. A study of computer-related upper limb discomfort and computer vision syndrome. J Hum Ergol (Tokyo) 2007 Dec;36(2):45-50. [PubMed]

2. Capon F, Cambie MP, Clinard F, et al. Occupational contact dermatitis caused by computer mice. Contact Dermatitis 1996 Jul;35(1):57-8. [PubMed]

3. Goossens A, Blondeel S, Zimerson E. Resorcinol monobenzoate: a potential sensitizer in a computer mouse. Contact Dermatitis 2002 Oct;47(4):235. [PubMed]

4. Kanerva L, Estlander T, Jolanki R. Occupational contact dermatitis caused by a personal-computer mouse. Contact Dermatitis 2000 Dec;43(6):362-3. [PubMed]

5. Garcia-Morales I, Garcia BB, Camacho MF. Occupational contact dermatitis caused by a personal-computer mouse mat. Contact Dermatitis 2003 Sep;49(3):172. [PubMed]

6. Vermeer MH, Bruynzeel DP. Mouse fingers, a new computer-related skin disorder. J Am Acad Dermatol 2001 Sep;45(3):477. [PubMed]

7. Johnson RC, Elston DM. Wrist dermatitis: contact allergy to neoprene in a keyboard wrist rest. Am J Contact Dermat 1997 Sep;8(3):172-4. [PubMed]

8. Bassiri S, Cohen DE. Bilateral palmar dermatitis. Am J Contact Dermat 2002 Jun;13(2):75-6. [PubMed]

9. Yokota M, Fox LP, Maibach HI. Bilateral palmar dermatitis possible caused by computer wrist rest. Contact Dermatitis 2007 Sep;57(3):192-3. [PubMed]

10. Lewis AT, Hsu S, Phillips RM, et al. Computer palms. J Am Acad Dermatol 2000 Jun;42(6):1073-5. [PubMed]

11. Tanaka M, Fujimoto A, Kobayashi S, et al. Keyboard wrist pad. Contact Dermatitis 2001 Apr;44(4):253-4. [PubMed]

12. Li JG, Feng YG, Feng J, et al. Mouse-related dermatosis. Int J Dermatol 2004 Nov;43(11):855-6. [PubMed]

13. Goksugur N, Cakici H. A new computer-associated occupational skin disorder: Mousing callus. J Am Acad Dermatol 2006 Aug;55(2):358-9. [PubMed]

14. Bachmeyer C, Bensaid P, Begon E. Laptop computer as a modern cause of erythema ab igne. J Eur Acad Dermatol Venereol 2009 Jun;23(6):736-7. [PubMed]

15. Jagtman BA. Erythema ab igne due to a laptop computer. Contact Dermatitis 2004 Feb;50(2):105. [PubMed]

16. Levinbook WS, Mallett J, Grant-Kels JM. Laptop computer--associated erythema ab igne. Cutis 2007 Oct;80(4):319-20. [PubMed]

17. Maalouf E, Simantov A, Rosenbaum F, et al. Erythema ab igne as an unexpected computer side-effect. Dermatology 2006;212(4):392-3. [PubMed]

18. Mohr MR, Scott KA, Pariser RM, et al. Laptop computer-induced erythema ab igne: a case report. Cutis 2007 Jan;79(1):59-60. [PubMed]

19. Bilic M, Adams BB. Erythema ab igne induced by a laptop computer. J Am Acad Dermatol 2004 Jun;50(6):973-4. [PubMed]

20. Kucuktas M, Demirkesen C, Aslan C, et al. Laptop-induced erythema ab igne. Clin Exp Dermatol 2010 Jun;35(4):449-50. [PubMed]

21. Rimmer S, Spielvogel RL. Dermatologic problems of musicians. J Am Acad Dermatol 1990 Apr;22(4):657-63. [PubMed]

22. Abanmi AA, Al Zouman AY, Al HH, et al. Prayer marks. Int J Dermatol 2002 Jul;41(7):411-4. [PubMed]

23. Freeman DB. Corns and calluses resulting from mechanical hyperkeratosis. Am Fam Physician 2002 Jun 1;65(11):2277-80. [PubMed]

24. Corea-Tellez KS, Bustamante-Montes P, Garcia-Fabila M, et al. Estimated risks of water and saliva contamination by phthalate diffusion from plasticized polyvinyl chloride. J Environ Health 2008 Oct;71(3):34-9, 45. [PubMed]

25. Ongenae K, Matthieu L, Constandt L, et al. Contact allergy to resorcinol monobenzoate. Dermatology 1998;196(4):470-3. [PubMed]

26. Kibbi AG, Tannous Z. Skin diseases caused by heat and cold. Clin Dermatol 1998 Jan;16(1):91-8. [PubMed]

27. Lapidoth M, Shafirstein G, Ben AD, et al. Reticulate erythema following diode laser-assisted hair removal: a new side effect of a common procedure. J Am Acad Dermatol 2004 Nov;51(5):774-7. [PubMed]

28. Donohue KG, Nahm WK, Badiavas E, et al. Hot pop brown spot: erythema Ab igne induced by heated popcorn. J Dermatol 2002 Mar;29(3):172-3. [PubMed]

29. Helm TN, Spigel GT, Helm KF. Erythema ab igne caused by a car heater. Cutis 1997 Feb;59(2):81-2. [PubMed]

30. Lin SJ, Hsu CJ, Chiu HC. Erythema ab igne caused by frequent hot bathing. Acta Derm Venereol 2002;82(6):478-9. [PubMed]

31. Hewitt JB, Sherif A, Kerr KM, et al. Merkel cell and squamous cell carcinomas arising in erythema ab igne. Br J Dermatol 1993 May;128(5):591-2. [PubMed]

32. Johansson O, Hilliges M, Bjornhagen V, et al. Skin changes in patients claiming to suffer from "screen dermatitis": a two-case open-field provocation study. Exp Dermatol 1994 Oct;3(5):234-8. [PubMed]

33. Berg M, Lonne-Rahm SB, Fischer T. Patients with visual display unit-related facial symptoms are stingers. Acta Derm Venereol 1998 Jan;78(1):44-5. [PubMed]

34. Gangi S, Johansson O. Skin changes in "screen dermatitis" versus classical UV- and ionizing irradiation-related damage—similarities and differences. Exp Dermatol 1997 Dec;6(6):283-91. [PubMed]

35. Eriksson N, Hoog J, Mild KH, et al. The psychosocial work environment and skin symptoms among visual display terminal workers: a case referent study. Int J Epidemiol 1997 Dec;26(6):1250-7. [PubMed]

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