Forensic Dermatology of Postmortem Tanning: A Unique Phenomenon That Can Occur After Death

Abstract

Postmortem tanning, previously referred to as either postmortem suntan or postmortem sunburn, presents as hyperpigmentation of sun-exposed uncovered skin. It most commonly occurs in decedents who remain in an environment in which the ambient temperature is either warm or hot; the areas of the corpse that are exposed to the sun develop hyperpigmentation. This postmortem change usually appears in the fresh (first) stage of decomposition. We describe three decedents who developed postmortem tanning. One of the women has an extensive severe darkening of her skin in the distribution where her skin was exposed to sunlight. The second woman had a localized band of pronounced tanning on her lower abdomen; associated early decomposition had occurred, including skin slippage and possible marbling of the superficial veins, at the location of the tanning. The third case, a young man, showed the concurrent presence of keratosis pilaris on his extensor arms that were affected by the tanning. In contrast to livor mortis, postmortem tanning occurs on the skin that is located on the non-dependent side of the body, those areas most apt to be exposed to sunlight. In living individuals, melanogenesis-associated tanning is usually an oxygen-dependent process. In decedents, blood flow and oxygen delivery to the skin that becomes darkened/hyperpigmented is not mandatory. Areas for future investigation include description of the histologic appearance of the tanned skin in comparison to adjacent, non-tanned skin, the incidence of postmortem tanning, the factors that may accelerate or decelerate the occurrence of postmortem tanning, and the possible correlation of the appearance of postmortem tanning as a feature that can be used to reveal information for estimating the postmortem interval.

Keywords: color; cutaneous; dermatology; forensic; melanogenesis; postmortem; radiation; sunburn; tanning; ultraviolet.

Figure 1. Severe postmortem tanning in a middle-aged Black woman

A middle-aged Black woman who had died was discovered with extensive sun-related hyperpigmentation. There was marked darkening of the skin exposed to the sun on her left flank, upper back, left posterior arm, left hip, left lateral lower extremity and right medial leg show dark hyperpigmentation (white stars). The tanned areas that had been exposed to the sun since she was found lying on her right side. The figure has previously been published; however, details of the case have not been previously reported. Republished with permission from Springer Nature from Prahlow JA, Byard RW. Postmortem changes and time of death (Chapter 8). In: Prahlow JA, Byard RW, eds. Atlas of Forensic Pathology. New York, New York. Springer Humana Press; 2012, page 158 [4].

Figure 2. Postmortem tanning on the lower abdomen of a young Caucasian woman

The hyperpigmentation from postmortem tanning on the right side (A) and left side (B) of the lower abdomen is sharply outlined within the area of sun-exposed skin that was not covered by clothing (white stars). In addition, skin dessication/slippage and early marbling of the superficial vessels which appears as darkening of the vessels is noted in the area of hyperpigmentation (white arrows). The black rectangle is covering a tattoo.

Figure 3. A young man with hyperpigmentation from postmortem tanning on sun-exposed skin

Postmortem tanning is present on the right side of his neck, the lower chest (beneath the right areola), abdomen, and lateral right arm (white stars). Keratosis pilaris, presenting as small follicular papules, is also present in the area of hyperpigmentation (within white ovals). The black rectangles are covering a tattoo.