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This issue of Photodermatology, Photoimmunology, and Photomedicine commemorates the contributions and legacy of Dr Nikiforos Kollias, an outstanding skin biophysicist affectionately known as "Nik" to those who worked and trained with and under him. Nik championed the use of noninvasive optical techniques such as spectroscopy of the skin to probe basic physiologic processes such as pigmentation and inflammation. More than just trying to understand how and why the skin could change its appearance and behavior following exposure to light, Nik actively sought to improve and advance practical biophotonic medical applications including sunscreens, photodynamic therapy, and optical imaging. [Extracted from the article]

Polymorphous light eruption ( PMLE) is the most common photodermatosis and is characterized by the development of a pruritic skin eruption within a few hours to days after sun or artificial light exposure. The eruption usually takes up to two weeks to resolve in the absence of further ultraviolet radiation. PMLE has been reported as a side effect of ultraviolet A1 ( UVA1) therapy but characteristics of the eruption, especially the duration until resolution after treatment, has not been described. A 37-year-old female developed an unusually persistent PMLE that lasted for 5 weeks after completion of UVA1 phototherapy. [ABSTRACT FROM AUTHOR]

Background/Purpose: A recent direction in skin disease classification is to develop quantitative diagnostic techniques. Skin relief, colloquially known as roughness, is an important clinical feature. The aim of this study is to demonstrate a novel polarization speckle technique to quantitatively measure roughness on skin lesions in vivo. We then calculate the average roughness of different types of skin lesions to determine the extent to which polarization speckle roughness measurements can be used to identify skin cancer. Methods: The experimental conditions were set to target the fine relief structure on the order of ten microns within a small field of view of 3 mm. The device was tested in a clinical study on patients with malignant and benign skin lesions that resemble cancer. The cancer group includes 37 malignant melanomas (MM), 43 basal cell carcinomas (BCC), and 26 squamous cell carcinomas (SCC), all categories confirmed by gold standard biopsy. The benign group includes 109 seborrheic keratoses (SK), 79 nevi, and 11 actinic keratoses (AK). Normal skin roughness was obtained for the same patients (301 different body sites proximal to the lesion). Results: The average root mean squared (rms) roughness ± standard error of the mean for MM and nevus was equal to 19 ± 5 μm and 21 ± 3 μm, respectively. Normal skin has rms roughness of 31 ± 3 μm, other lesions have roughness of 35 ± 10 μm (AK), 35 ± 7 μm (SCC), 31 ± 4 μm (SK), and 30 ± 5 μm (BCC). Conclusion: An independent‐samples Kruskal–Wallis test indicates that MM and nevus can be separated from each of the tested types of lesions, except each other. These results quantify clinical knowledge of lesion roughness and could be useful for optical cancer detection. [ABSTRACT FROM AUTHOR]

The article describes the case of a 32-year-old Caucasian male with cutaneous larva migrans(CLM). The man had a three-week history of a pruritic eruption on the left foot. Result of the polarized dermoscopy of the serpiginous tract revealed two oval structures, with yellow peripheries and brown centers. It presents an overview on CLM, which is commonly found in tropical and subtropical geographic areas caused by animal hookworm larvae.

A letter to the editor is presented related to a patient suffering from segmental confetti dyschromatosis.

Background: Biases inherent in self‐assessment of sun exposure and sun‐safe behavior may lead to inaccurate conclusions about the effectiveness of sun‐safety educational programs. Objectives: We aimed to compare self‐reports to objective measures of sun exposure, when examining the effectiveness of passive versus active educational interventions. Methods: From May to June 2018, 73 participants recruited at a dermatology clinic were sequentially assigned to receive sun‐safety education through one of 3 modes: interactive online module, video, or no education. A baseline Sun Exposure and Behavior Inventory (SEBI) questionnaire was administered, and spectrophotometric measurements of sun‐exposed and sun‐protected areas were taken and reported in the CIE L*a*b* color space. Participants were followed 4–8 and 16 weeks after the initial visit where the SEBI was re‐administered, and serial measurements of skin color were taken. The change in SEBI scores and L*a*b values, as calculated by the individual typology angle (ITA°), was analyzed. Results: There was a significant increase in skin darkening in all the groups at 4–8 and 16 weeks follow‐up. There was no statistically significant difference between the groups in the magnitude of color change. However, subjectively at 4‐8 weeks post‐intervention, participants in the interactive module and video groups had significantly improved self‐reported SEBI scores compared to control (p <.05, Kruskal‐Wallis). By 16 weeks, only the interactive module group showed significant improvement in SEBI scores compared to control (p <.05, ANOVA). Conclusion: In determining the effectiveness of sun‐safety programs, spectrophotometric evaluation of sun‐induced skin pigmentation can allow for a more complete evaluation of self‐reported sun exposure and sun‐protective behavior. [ABSTRACT FROM AUTHOR]

Summary: Background and Purpose: Although cutaneous autofluorescence has been utilized for evaluation of skin conditions, there is a paucity of data on normal human skin autofluorescence and its dependence on anatomical site. The objective of this study is to use excitation‐emission matrix spectroscopy to quantify and characterize skin autofluorescence at different body sites. Methods: Ten anatomical sites from 30 healthy volunteers were measured with a double‐grating excitation‐emission matrix spectrofluorometer. Results: For the 10 body sites evaluated, there were four overall patterns of autofluorescence: skin from the head and neck exhibits high superficial and low bilayer fluorescence; the dorsal forearm and dorsal hand have both low superficial and bilayer fluorescence; the upper inner arm and back have high superficial and intermediate bilayer fluorescence; while the palm and thumbnail have both high superficial and bilayer fluorescence. The corresponding fluorescence excitation‐emission peaks for these patterns were as follows: head and neck, 3 peaks at 290‐300/330‐350, 360‐380/460‐485, and 380‐420/610‐630 nm; dorsal forearm and dorsal hand, 2 peaks around 295‐300/345‐360 and 385‐395/460‐485 nm; upper inner arm and back, 3 peaks around 295‐300/335‐355, 335‐340/390‐410, and 375‐390/455‐480 nm; palm and thumbnail, 3 peaks around 285‐300/345‐355, 335‐345/390‐410, and 365‐390/450‐480 nm. Conclusion: Cutaneous fluorescence varies in distinct patterns according to anatomical site, due to the component fluorophores present, skin thickness, and the degree of melanization and long term sun exposure. These EEM patterns for normal skin should be accounted for when interpreting fluorescence signals from disease states and can also be used to guide the selection of optimal wavebands when applying this optical modality. [ABSTRACT FROM AUTHOR]

Summary: Background: There is no accepted method to objectively assess the visual appearance of sunscreens on the skin. Methods: We present a method for sunscreen application, digital photography, and computer analysis to quantify the appearance of the skin after sunscreen application. Four sunscreen lotions were applied randomly at densities of 0.5, 1.0, 1.5, and 2.0 mg/cm2 to areas of the back of 29 subjects. Each application site had a matched contralateral control area. High‐resolution standardized photographs including a color card were taken after sunscreen application. After color balance correction, CIE L*a*b* color values were extracted from paired sites. Differences in skin appearance attributed to sunscreen were represented by ΔE, which in turn was calculated from the linear Euclidean distance within the L*a*b* color space between the paired sites. Results: Sunscreen visibility as measured by median ΔE varied across different products and application densities and ranged between 1.2 and 12.1. The visibility of sunscreens varied according to product SPF, composition (organic vs inorganic), presence of tint, and baseline b* of skin (P < .05 for all). Conclusion: Standardized sunscreen application followed by digital photography and indirect computer‐based colorimetry represents a potential method to objectively quantify visibility of sunscreen on the skin. [ABSTRACT FROM AUTHOR]

Background Recent advances in biomedical optics have enabled dermal and epidermal components to be visualized at subcellular resolution and assessed noninvasively. Multiphoton microscopy ( MPM) and reflectance confocal microscopy ( RCM) are noninvasive imaging modalities that have demonstrated promising results in imaging skin micromorphology, and which provide complementary information regarding skin components. This study assesses whether combined MPM/ RCM can visualize intracellular and extracellular melanin granules in the epidermis and dermis of normal human skin. Methods We perform MPM and RCM imaging of in vivo and ex vivo skin in the infrared domain. The inherent three-dimensional optical sectioning capability of MPM/ RCM is used to image high-contrast granular features across skin depths ranging from 50 to 90 μm. The optical images thus obtained were correlated with conventional histologic examination including melanin-specific staining of ex vivo specimens. Results MPM revealed highly fluorescent granular structures below the dermal-epidermal junction ( DEJ) region. Histochemical staining also demonstrated melanin-containing granules that correlate well in size and location with the granular fluorescent structures observed in MPM. Furthermore, the MPM fluorescence excitation wavelength and RCM reflectance of cell culture-derived melanin were equivalent to those of the granules. Conclusion This study suggests that MPM can noninvasively visualize and quantify subepidermal melanin in situ. [ABSTRACT FROM AUTHOR]

Background Skin cancer is the most common type of cancer in humans. Current techniques for identifying normal and neoplastic tissues are either destructive or not sensitive and specific enough. Raman spectroscopy and confocal imaging may obviate many limitations of existing methods by providing noninvasive, high-resolution, and real-time morphological and biochemical analysis of living tissues and cells. Methods We conducted micro- Raman spectroscopy studies on HaCaT cells, melanocytes ( MC) and their malignant counterparts squamous cell carcinoma ( SCC) and melanoma ( MM) cells, respectively. Reflectance confocal imaging is used as guidance for the spectral measurements. Results Significant differences were found between the spectra of HaCaT cells and SCC cells, MC cells and MM cells, as well as all normal cells ( HaCaT and MC) and all tumor cells ( SCC and MM). Approximately 90% sensitivity and specificity was achieved for all the separations that we performed. Conclusion Our results demonstrated the robust capability of confocal Raman spectroscopy in separating different cell lines. The acquired Raman spectra of major types of skin cells and their malignant counterparts will be useful for the interpretation of Raman spectra from in vivo skin. We believe it will eventually help diagnosis of skin cancer and other skin disease in clinical dermatology. [ABSTRACT FROM AUTHOR]

Background: Spectroscopic methods have been used to analyze in vivo melanin in the past but the specific effect of melanin depth on autofluorescence and reflectance spectroscopy has not been determined. In patients with blue vitiligo, three distinctive clinicopathologic patterns are present: (1) normal skin with normal epidermal melanin pigmentation (2), skin of blue vitiligo with dermal melanin pigmentation, and (3) tissue of regular vitiligo with no melanin pigmentation. Blue vitiligo may thus serve as an in vivo model to assess dermal pigment using spectroscopic techniques. Objectives: To evaluate the reflectance and autofluorescence spectra of a patient with blue vitiligo in order to assess the effect of melanin pigmentation and its localization on the optical properties of the skin. Methods: The blue-gray, normal and depigmented lesions of a patient with blue vitiligo were analyzed using reflectance and fluorescent spectroscopy. The condition was likely induced by a phototoxic reaction in a patient with pre-existing vitiligo. These data were then correlated to the histologic and electron microscopic findings present in the various types of lesions. Results: Reflectance spectroscopy detected little difference in spectral shape between skin sites affected by blue vitiligo vs. vitiligo. Autofluorescence spectroscopy detected an apparent difference between the two types of lesions, with the blue–gray lesions (blue vitiligo) showing lower fluorescence intensity and spectral maximum position red-shifted compared with regular vitiligo, whereas regular vitilgo showed more intense hemoglobin absorption than the blue vitiligo. Conclusions: Dermal melanin present in blue vitiligo can be well characterized by autofluorescence spectroscopy, while little difference in reflectance spectral shape exists between vitiligo and blue vitiligo. Thus, autofluorescence spectroscopy may better identify deeper structures in skin tissue, such as melanin, than reflectance spectroscopy [ABSTRACT FROM AUTHOR]