Forensic evaluation of occupational marks in establishing identity—A case report

1. Introduction 

The living have responsibilities for the dead; and in particular, civilized societies recognize the need for identity both during life and at death [1]. Identification of a dead body is easy, when accompanied by relatives or friends. However it becomes equally difficult to identify, when an unknown body is summoned for medico-legal autopsy. Numerous methods exist for the identification of unknown human body or human remains and all have their advantages and disadvantages; which include visual identification, fingerprints, the presence of medical prostheses, odontological techniques and of course DNA fingerprinting [2].

One more important and less spoken forensic tool to establish identity in an unknown deceased is occupational skin lesions acquired in the course of his or her daily profession. Different occupations produce characteristic effect on different parts of body due to use of tools or machines or exposure to different chemicals in the working environment. Variants of occupational marks may occur during the course of the profession like, rough hands seen in manual labourer involved in construction work, excavated chest in a cobbler, callosities of finger tips in a stenographer, callosities of palm at the base of fingers in butchers, burn scars over the back of both hands seen in blacksmiths, involuntary permanent tattooing of micro particles of coal found on the hands of the labourers involved in mining industry [3].

The postmortem surgeon should have a comprehensive knowledge of different common occupations in the locality, which may aid in fixing a reasonable identity to the body. Establishing identity based on occupational skin marks in an unknown individual is rarely reported in forensic literatures. We report a rare and unusual case, where the identity of an unknown elderly male who committed suicide by hanging was established based on the symmetrical distribution and pattern of skin lesions acquired during the course of his occupation.

2. Case report 

A 55- year-old Caucasian man, who was unknown to the neighboring vicinity, was found hanging from a tree in an unsecured area. The body was discovered by the public, who informed the investigating authorities. A cotton cloth was found encircling his neck. A medico-legal autopsy was performed. The deceased was 185cm in length and weighed 57kg. External examination revealed rigor present all over the body, with hypostasis on the lower abdomen, both forearms and legs. Tardieu spots were present, involving the lower legs and feet. Petechial haemorrhages were present in the conjunctivae. The tongue was bitten, with slight protrusion from the oral cavity and had a dark brown appearance due to drying. Dried salivary stains were present, along the right angle of mouth.

A blue colored checked cotton cloth encircled the decedent's neck. This was knotted posteriorly on the left side below the ear (Fig. 1). Removal of the ligature material, revealed a reddish -brown parchmentised pressure abrasion, which partially encircled the neck directing obliquely upwards and backwards above the level of thyroid cartilage, measuring 28cm in length and 4cm in width. Anterior neck dissection showed fracture of the superior horns of the thyroid cartilage with surrounding contusions. Routine toxicology was unremarkable. At the end of autopsy, there was no doubt regarding either to the cause or manner of death. Only the concern raised by the medico-legal death investigator, was regarding the identity of the deceased. The decedent carried no evidence of identification, other than the blue colored ligature material and the worn apparels.

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Fig. 1. A ligature material encircling the decedent's neck with a fixed knot on the left side below the ear.

On examination, unusual skin lesions were present symmetrically over both hands and ankle joint. Skin over the inner aspect of both hands were hypo pigmented, dry, raised with irregular surface and lichenified involving an area of 5cm×3cm (Fig. 2). The skin over the front and outer aspect of both ankle joints and foot were hypo pigmented, dry, raised with irregular surface and lichenified spread over an area of 7cm×4cm (Figs. 3 and 4). Bilateral palms and soles showed focal yellowish callosities with loss of dermatoglyphic markings. Similar types of skin lesions were not present on any other part of the decedent's body. Nails were normal in architecture. No evidence of erythema, fresh cuts, abrasions or erosions was seen on the skin. Based on the distribution and symmetrical pattern of these skin lesions over both hands and foot, a provisional conclusion of frictional occupational dermatosis was made, where probably the deceased was either a coconut tree or a coconut palm tree climber. Based on this piece of vital information, the investigating authorities were successful in establishing his identity and the family members revealed that the decedent was a professional coconut tree climber since 35 years, who earned his livelihood only by plucking coconuts which was not sufficient to support his family members. He was depressed due to strained economic status, which made him to end his life.

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Fig. 2. Hypo pigmented, lichenified skin lesions over the inner aspect of both hands.

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Figs. 3 and 4. Hypo pigmented, lichenified skin lesions over the front and outer aspect of foot.

3. Discussion 

Mechanical trauma, an accompaniment of many occupations, is the primary factor in approximately 6% cases of occupational skin diseases [4]. Friction is the most common type of mechanical trauma, ranging from mild interrupted friction, producing lichenification and hyperpigmentation, to heavier and more persistent friction, which produces callosities and nail damage [5]. Friction blisters can also occur with sudden shearing force, but it seldom occurs on loose skin which stretches easily. Occupational marks are effects of a particular occupation on the worker's skin [4], [6]. Occupational dermatosis were reported in beedi rollers which ranged from callosities of the fingers and feet to nail pigmentation, paronychia, dystrophy due to constant use of scissors for cutting leaves and use of gum and artificial metallic nails for rolling beedis [7]. Occupational cuts on the tips of the index finger and thumb were reported in opticians during the preparation of lenses [3].

Various occupations like plumbing, pipe fitting, machining, postal work, solid waste handling, athletes, musicians, computer operators, and data-entry typists have been reported to have occupational marks [5]. The most prevalent skin disorders of instrumental musicians, in particular string instrumentalists (e.g., violinists, cellists, guitarists), woodwind players (e.g., flautists, clarinetists), and brass instrumentalists (e.g., trumpeters), include a variety of allergic contact sensitizations (e.g., colophony, nickel, and exotic woods) and irritant (physical–chemical noxae) skin conditions whose clinical presentation and localization are usually specific for the instrument used (e.g., “fiddler's neck”, “cellist's chest”, “guitar nipple”, “flautist's chin”) [8], [3]. Skin infections such as herpes labialis seem to be a more common skin problem in woodwind and brass instrumentalists [8]. Skin conditions may be a significant problem not only in professional instrumentalists, but also in musicians of all ages and ability [8]. Today with increasing automation, less frequent manual operation of tools, better protective clothing, such occupational marks have become less frequent [9].

Coconut tree climbing is practised in various parts of Australia, Africa, Islands of Lakshadweep, Middle East, South East Asia and in India. Coconut and palm tree climbing is one of the modes of occupation of the people living in various parts of Southern Indian states of Andhra Pradesh, Kerala, Karnataka and Tamil Nadu [5], [6]. The technique of gripping the coconut tree with both hands and feet, and then pushing up the body to climb higher, results in intermittent pressure over the forearm skin, palms, and soles. In response to friction, there is a steady rate of increase in epidermal turnover, and laying down of thickened, vertically oriented collagen bundles in papillary dermis, resulting in lichenification [5]. In our case, after the identity was established by the decedent's relatives, an attempt was made to retrospectively analyze the distribution and pattern of the skin lesions over the hands and foot.

In the coastal part of Karnataka and Kerala (Southern India), commonly a professional coconut climber uses coir rope, or nylon gunny bag twisted in the form of loop as support, to grip the tree with both feet and forearms while climbing to pluck coconuts (Figs. 5 and 6). While climbing with effort the inner aspect of the palm and the forearm come in contact with the bark of the coconut tree (Fig. 7), the extensor surface of the foot come in contact with the gripper (Fig. 8), where in these areas the skin will be subjected to persistent friction which, probably has resulted in symmetrical pattern of distribution of skin lesion, acquired as a part of his occupation.

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Fig. 5. Loop made of nylon gunny bags used as gripper by coconut tree climbers.

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Fig. 6. The technique of gripping the tree with both hands and feet, and then pushing up the body to climb.

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Figs. 7 and 8. While climbing, the inner aspect of the palm and the forearm come in contact with the bark of the coconut tree, the extensor surface of the foot come in contact with the gripper.

Conflict of interest 

All authors have read the final version of the manuscript, and approved the same. The authors received no specific funding for the aforementioned manuscript. None of the authors have a conflict of interest to declare.