Skin colour changes during experimentally-induced sickness

Abstract

Skin colour may be an important cue to detect sickness in humans but how skin colour changes with acute sickness is currently unknown. To determine possible colour changes, 22 healthy Caucasian participants were injected twice, once with lipopolysaccharide (LPS, at a dose of 2ng/kg body weight) and once with placebo (saline), in a randomised cross-over design study. Skin colour across 3 arm and 3 face locations was recorded spectrophotometrically over a period of 8h in terms of lightness (L), redness (a) and yellowness (b) in a manner that is consistent with human colour perception. In addition, carotenoid status was assessed as we predicted that a decrease it skin yellowness would reflect a drop in skin carotenoids. We found an early change in skin colouration 1-3h post LPS injection with facial skin becoming lighter and less red whilst arm skin become darker but also less red and less yellow. The LPS injection also caused a drop in plasma carotenoids from 3h onwards. However, the timing of the carotenoid changes was not consistent with the skin colour changes suggesting that other mechanisms, such as a reduction of blood perfusion, oxygenation or composition. This is the first experimental study characterising skin colour associated with acute illness, and shows that changes occur early in the development of the sickness response. Colour changes may serve as a cue to health, prompting actions from others in terms of care-giving or disease avoidance. Specific mechanisms underlying these colour changes require further investigation.

Behavioral and neural correlates to multisensory detection of sick humans

“…We further predicted that sickness cues compared with healthy ones would evoke enhanced blood oxygen level-dependent (BOLD) changes in the odor-perception network (piriform cortex, orbitofrontal cortex, and amygdala) and in the face-perception network (fusiform gyrus, inferior and superior frontal gyrus, and amygdala). This prediction was based on previous studies demonstrating sickness-driven changes in body odors (12) and facial appearance (23) and on several studies indicating salience-and threat-driven changes in the respective olfaction-(24) and vision-(25) processing networks.…”

Cultural differences in preferences for facial coloration

“…However, evidence that facial coloration is associated with measures of susceptibility to infectious diseases is equivocal Henderson et al, 2017;Phalane et al, 2017).…”

Human colour in mate choice and competition

“…Further studies have indicated that yellower and redder skin is also more attractive in male faces [37,38]. Skin yellowness and redness are probably linked to health and attractiveness because these colour properties vary with current health [39].…”