Toxic erythema as the first sign of COVID‐19 infection

Abstract

linear polarizers.Liquid-crystalline materials with lamellar arrangements exhibit anisotropic optical properties, not cubic arrangement ones, thus we believe the lamellar or compact hyperkeratosis acts as an optically anisotropic substance and produces SWS under polarized dermoscopy (Fig. 2f). 5 A toggle of light from polarized to nonpolarized mode will render a better appreciation of the colour and morphology of WS (Fig. 1).The colour of WS, in our study, varied from brilliant white to grey-white to blue-white.The brilliant-white colour was observed when the background was pink (without pigment incontinence) and blue-white when the background was blue-grey (with pigment incontinence) (Fig. 1).The background/perilesional colour appeared more greyish and dull under the nonpolarized mode, whereas it appeared brighter and more bluish under polarized mode.Similarly, the vascular structures were brighter and more focused under polarized mode (Fig. 2a,b).The commonest vascular structure noticed was the dotted vessels in a peripheral distribution followed by uniform and unspecific distribution.In addition to WS, comedo-like opening, linear-irregular crypt, scales and keratotic plugging were better appreciated under nonpolarized mode.Under dry dermoscopy (10 patients, 25 lesions; data not shown), the colour and distribution of the scales were distinctly visible, but the overlying scales hindered the appearance of SWS, WS, vascular structures, and at times comedonal and linear-irregular crypts (Fig. 2).The study limitations included its retrospective nature, inclusion of a relatively small number of lesions, and enrolment of patients of only two phototypes.In conclusion, we have delineated the differences in various dermoscopic features of LP observed under polarized vs. nonpolarized mode.The visibility of WS, which is better appreciated under nonpolarized light, can be obscured by the SWS.It is therefore necessary to toggle from polarized to nonpolarized mode to differentiate between SWS and WS and to better visualize WS.

Abstract

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