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PubMedDate not supplied

Clinical and dermatoscopic diagnosis of small pigmented skin lesions.

Small pigmented skin lesions represent a new challenge for all physicians devoted to the early diagnosis of melanoma. The purpose of this prospective study was to establish the diagnostic value of the clinical and the dermatoscopic examinations in a population of 157 consecutive patients with 161 small (< or = 6 mm) pigmented lesions, recruited in a short time. Of these 161 lesions, 13 were thin melanomas (median thickness 0.49 mm). In this population, clinical evaluation produced a diagnostic sensitivity of 77% and a specificity of 74%. Dermatoscopy resulted in a sensitivity of 77% and in a specificity of 72%. Combining clinical and dermatoscopic evaluations all the melanomas were preoperatively recognised. The results of the present study stress the complementary role of clinical and dermatoscopic examinations. In particular, clinical evaluation remains of utmost importance in diagnosing melanoma. This concept must be stressed in the education and training of young dermatologists.

Adolescent↗
PubMed1998

Interdependence of eye and hair colour, skin type and skin pigmentation in a Caucasian population.

Eye colour, hair colour and skin colour are important risk factors for malignant melanoma and non-melanoma skin cancers. There are few studies in which the distribution of these pigmentary factors in risk populations has been assessed. The purpose of this study was to investigate the prevalence of the major eye and hair colours and the distribution of skin types and skin pigmentation in a Caucasian population. In 892 Danish Caucasians, eye colour, hair colour and skin type were assessed and facultative and constitutive skin pigmentation were measured objectively using skin reflectance spectroscopy. Blue eye colour and blond hair colour and skin type II were the most frequent (60%, 67% and 33% of subjects, respectively). All four major eye colours and four major hair colours (with the exception of red hair colour) were found within skin types I-IV and we could not predict the skin type or the constitutive skin pigmentation. Skin type could not be taken to classify individuals reliably according to their facultative or constitutive skin pigmentation.

Adolescent↗
PubMed1983

Specimen holder improvements for the study of amphibian skin pigmentation.

A skin specimen holder was constructed permitting nearly identical experimental conditions during in vitro spectrophotometry and photomicrography of amphibian skin melanocytes. The specimen holder was made of non-corrosive steel thread and made to fit a spectrophotometer cuvette and the light microscope stage. The improvements were compared to earlier constructions.

Animals↗
PubMed2001

Autofluorescence of human skin is age-related after correction for skin pigmentation and redness.

When measuring the skin fluorescence in vivo, the absorption of chromophores such as melanin and hemoglobin often contribute predominantly to the changes in fluorescence and obscure the information from the fluorophores. We measured in vivo the collagen-linked 375 nm fluorescence (excitation: 330 nm) and 455 nm fluorescence (excitation: 370 nm) from nonexposed buttock skin of healthy volunteers. Skin pigmentation and redness of the same sites were quantified by reflectance of the skin at 555 nm and 660 nm. Multiple regression analysis was used to find the correlation between the fluorescence and skin pigmentation and redness. The fluorescence was corrected for the impact of pigmentation and redness according to the equation found in the regression analyses. The age-related trend of the fluorescence was evaluated. The 375 nm fluorescence showed positive relation to age, whereas the 455 nm fluorescence showed no significant relation to age. The increasing rate of the 375 nm fluorescence (logarithm transformed) was 2% per year, which is comparable with previously published data. The results suggest that the correction of the autofluorescence intensity for skin pigmentation and redness is valid, and the 375 nm skin autofluorescence may be used as a biologic marker of skin aging in vivo.

Adult↗
PubMed1996

Growth hormone-secreting pituitary adenoma associated with multiple bone cysts, skin pigmentation and aortitis syndrome.

McCune-Albright syndrome (MAS) is clinically characterized by polyostotic fibrous dysplasia, cafe au lait pigmentation of the skin and multiple endocrinopathies. Recently activating mutations of codon 201 in the gene encoding Gs alpha have been found in affected tissues in MAS. Herein we report a case of acromegaly associated with multiple bone cysts and skin pigmentation in a 47-year-old women. She had suffered a history of aortitis syndrome. The DNA sequence indicated that a Cys201 for Arg201 substitution was found in the GH secreting pituitary adenoma tissue but not in peripheral mononuclear cells. We speculate that the patient has a possible variant from of MAS characterized by multiple bone lesions skin pigmentation and GH-secreting pituitary adenoma.

Adenoma↗
PubMed1995

Fractal and integer-dimensional geometric analysis of pigmented skin lesions.

Accurate in vivo diagnosis of pigmented skin lesions is required to identify and excise malignant melanomas but to avoid unnecessary excision of benign lesions; the published rates of clinical diagnostic accuracy are about 65%. This study investigates whether fractal geometric analysis of pigmented skin lesions can improve the rate of diagnostic accuracy. Forty-two pigmented skin lesions (15 malignant melanomas, 21 melanocytic naevi, and 6 basal cell papillomas) on patients attending a dermatology clinic were photographed, excised, and sent for histopathological examination. The fractal dimension of the boundary of the lesions was measured using a box-counting method implemented on a microcomputer-based image analysis system. Euclidean geometric parameters were also measured. The fractal dimension of all the lesions was greater than the topological dimension (one), indicating that there is a fractal element to their structure. Using all measured parameters together, multivariate linear discriminant analysis produced a confusion matrix in which 45% of the lesions were assigned to the correct diagnostic group with a kappa statistic of 0.33. There was no significant difference between the fractal dimension of melanocytic naevi and that of malignant melanomas (p = 0.18). Although pigmented skin lesions have a fractal element to their structure, the fractal dimension of their boundaries is not a useful morphometric discriminant between the diagnostic groups of malignant melanomas and benign melanocytic naevi.

Algorithms↗
PubMedDate not supplied

Blood stasis contributions to the perception of skin pigmentation.

The chromatic characteristics of skin color arise from the interactions of light (primarily absorption and scattering) with the epidermis and the dermis. The primary light absorbers in skin are hemoglobin and melanin. Most of scattering is attributed to collagen fibers and in pigmented skin to melanosomes. Traditionally skin redness is considered to arise due to locally elevated concentrations of hemoglobin, whereas skin pigmentation is attributed to melanin. In this study we attempt to understand better the contributions of these chromophores to the perceived skin color using spectral analysis of skin color reactions induced by ultraviolet (UV) irradiation or pressure. In the first experiment 12 individuals with skin phototypes III-IV were irradiated on the back using a solar simulator with doses ranging from 0.7 to 3 MED. The skin reactions were evaluated on days 1, 7, 14, and 21 after irradiation. Evaluations included diffuse reflectance spectroscopy (DRS) and clinical assessment of the erythema and the pigment reaction. Apparent concentrations of melanin, oxy-, and deoxy-hemoglobin were calculated from the absorption spectra. In the second experiment the levels of deoxy-hemoglobin of the volar forearm of ten volunteers were selectively altered by either application of a pressure cuff or by topical application of 3% H(2)O(2). Changes in skin color appearance were documented by photography, colorimetry, and DRS. In the UV exposure experiment all reactions were dose dependent. Oxy-hemoglobin values increased to a maximum on day 1, correlating well with the clinical evaluation of erythema, and then decreased exponentially to base line. Melanin showed a significant increase on day 7 and remained relatively constant for the next 3 weeks, correlating well with the clinical evaluation of pigmentation (tanning). Deoxy-hemoglobin increased slightly on day 1 and remained elevated for the next 2 weeks. Thus, deoxy-hemoglobin correlated moderately with the clinical erythema scoring on day 1 only, while it contributes significantly to what is clinically perceived as skin tanning on days 7 and 14. Application of pressure below the diastolic level increased deoxy-hemoglobin concentration as measured by DRS. This increase corresponded to a decrease of a "pigmentation" parameter (based on the L(*)a(*)b(*) scale) in a similar fashion that has been documented for increases in melanin concentration. Topical H(2)O(2) application reduced deoxy-hemoglobin levels as measured by DRS. This reduction coincided kinetically with a visible skin blanching. Application of pressure or H(2)O(2) did not significantly alter the levels of oxy-hemoglobin or melanin. In this report we present compelling evidence that deoxy-hemoglobin significantly contributes to the skin color appearance. Blood pooling, expressed as increased deoxy-hemoglobin, can contribute to what is visually perceived as pigmentation. Furthermore, we present that measurement of its contribution to the skin color appearance can only be accomplished with DRS.

Administration, Topical↗
PubMed2004

Non-invasive measurements of skin pigmentation in situ.

Objective in situ measurements of skin pigmentation are needed for accurate documentation of pigmentation disorders, in studies of constitutive and induced skin pigmentation, for testing of the efficacy of pro-pigmentation or de-pigmentation agents, etc. Non-invasive instrumental measurements of skin pigmentation have been used for many decades. All are based on the ability of melanin to attenuate light. However, hemoglobin in dermal capillaries also attenuates light and needs to be accounted for when pigmentation is assessed. The methods under consideration include: (a) single point measurements, in which light reflected from a defined skin area is collected and a pigment index is calculated representing the average pigmentation over the examined area, and (b) imaging methods that attempt to generate a concentration distribution map of melanin pigment for the skin area being imaged. In this article, we describe the potentials and the limitations of the different approaches to both single point and imaging methods.

Dermoscopy↗
PubMed2004

Prevention of ultraviolet-induced skin pigmentation.

BACKGROUND/PURPOSE: Exposure to ultraviolet (UV) radiation increases skin pigmentation and usually results in an even darkening of the skin. However, it may also occasionally lead to the development of hyperpigmented lesions due to a local overproduction of pigment. Skin pigmentation is induced both by UVB and UVA rays. METHODS: The in vivo protection by sunscreens against pigmentation was studied using the determination of a level of protection against pigmentation based on the standardized sun protection factor (SPF) test method. The method includes delayed UVB and UVA pigmentations. The level of prevention against pigmentation was determined 7 days after exposure to solar-simulated radiation by visual assessment. It was calculated using the ratio of the minimal pigmenting dose on protected skin to the minimal pigmenting dose on unprotected skin. Broadspectrum UVB/UVA filters, Mexoryl SX and Mexoryl XL, and complete formula were tested. RESULTS: Protection against pigmentation correlates with the concentration of Mexoryl SX. The levels of protection obtained show a synergetic effect of Mexoryl SX when associated with Mexoryl XL. When different products having the same SPF (same protection against erythema) and different levels of UVA protection are compared, only sunscreen products with a high level of UVA protection show a similar level of protection against sunburn and pigmentation. Products with low UVA protection have a lower capacity of preventing induced pigmentation compared with their efficacy against erythema. CONCLUSIONS: These studies have evidenced that SPF determination was not sufficient to account for the efficiency in preventing pigmentation and that UVA protection was an essential part of this prevention.

Adolescent↗
PubMed1998

Facultative skin pigmentation in caucasians: an objective biological indicator of lifetime exposure to ultraviolet radiation?

To investigate age and gender trends in facultative and constitutive skin pigmentation we measured skin pigmentation non-invasively and objectively by skin reflectance spectroscopy in 653 caucasians (336 females and 317 males; mean age 38 years, range 0-85) who were not using artificial tanning devices. In all subjects, measurements were performed in the late winter and pre-spring period at five sites exposed to ultraviolet (UV) radiation: the forehead, the upper chest, the upper back and the lateral and medial aspects of the upper arm, and in UV-unexposed buttock skin. Constitutive pigmentation at the buttocks was highest in the first years of life and then decreased substantially during the first two decades of life (P < 0.01). After the age of 25 years, buttock pigmentation remained at a constant level (P = 0.20). There was no gender difference in constitutive pigmentation. Facultative skin pigmentation increased with age for all the measured sites with the highest levels found at the lateral aspect of the upper arm. Based on observations in this study we propose the idea of a 'sun exposure index' (SEI) for individuals, based on objective measurements of skin pigmentation. The SEI is calculated as the increase in facultative pigmentation above the constitutive level and is expressed as a percentage of the constitutive level. The SEI appeared to be related to cumulative lifetime UV exposure and may be used in epidemiological research as an objective estimate of UV exposure at different body sites in caucasians.

Adolescent↗
PubMedDate not supplied

Skeletal disorders associated with skin pigmentation: a role of melatonin?

Although frequently encountered, no available consensus about the association between skeletal abnormalities and skin pigmentation. Several syndromes are characterized by the presence of skin pigmentation in association with skeletal disorders like neurofibroamtosis 1, McCune-Albright Syndrome, Jaffe-Campanacci Syndrome and Jaffe-Lichtenstein Syndrome. Even in the absence of these syndromes, skeletal abnormalities were detected in all radiologically examined patients having patterned skin pigmentation. Although skin pigmentation is controlled by several factors, melatonin is the most reliable factor to have relation to development of skeletal abnormalities. Recent research works support that melatonin might play a role in bone development and several hypotheses link melatonin with some bone diseases associated with skin pigmentation. It seems that melatonin deficiency is a probable operating co-factor in a lot of clinical situations characterized by skin pigmentation and skeletal disorders. This would explain some of the un-explained observations related to these syndromes and research works along these lines might lead to the development of efficient treatment for these diseases.

Bone Diseases↗
PubMed1997

Epidermal thickness, skin pigmentation and constitutive photosensitivity.

The important factors for UV sensitivity in humans are considered to be the skin pigmentation and the epidermal thickness. In this study on 73 Caucasians (age 20-85 years), we investigated in UV unexposed buttock skin the relationship between the UV sensitivity and constitutive skin pigmentation and thickness of the stratum corneum and the cellular part of the epidermis, in 34 normal people and in 39 skin cancer patients (20) patients with cutaneous malignant melanoma and 19 patients with basal cell carcinoma of the skin). Skin pigmentation was measured by skin reflectance spectroscopy, and UV sensitivity by phototest with a solar simulator. Thicknesses of the stratum corneum and the cellular part of the epidermis were determined by light microscopic evaluation of skin biopsies from the phototest areas. We found that epidermal thickness was independent of skin type and was not correlated to constitutive skin pigmentation. Thickness of the stratum corneum was statistically not different in normal persons and in skin cancer patients (P = 0.41) and was independent of gender (P = 0.61) and age (P = 0.56), while thickness of the cellular epidermis decreased with age (P < 0.01). Stratum corneum thickness was found to be of minor importance for the constitutive UV sensitivity (accounting for on average 11% of the total photoprotection), which was mainly determined by the constitutive skin pigmentation (goodness-of-fit for correlation r = 0.83). A theoretical model for the relationship of UV dose to induction of clinical erythema grade and skin pigmentation and thickness of the stratum corneum was developed. Objective measurements of skin pigmentation in UV unexposed skin by skin reflectance spectroscopy in Caucasians, normal people and people with cutaneous malignant melanoma and basal cell carcinoma of the skin predicts the constitutive UV sensitivity with a high degree of precision.

Adult↗
PubMedDate not supplied

Wound care for patients with darkly pigmented skin.

This article examines the main skin or wound assessment parameters used for patients with darkly pigmented skin. Differences in skin pigmentation are discussed along with the challenges health professionals encounter in clinical practice and why linking theory to practice is vital.

Cicatrix↗
PubMedDate not supplied

Evaluation of the analgesic efficacy of EMLA cream in volunteers with differing skin pigmentation undergoing venipuncture.

BACKGROUND AND OBJECTIVES: Lidocaine/prilocaine cream (EMLA) applied to intact skin for 60 minutes has been shown to reduce venipuncture pain. Recent studies have suggested that lidocaine/prilocaine cream is less effective on heavily pigmented skin. The objective of this study was to evaluate the topical anesthetic efficacy of lidocaine/prilocaine cream in volunteers with varying skin pigmentation types. METHODS: Sixty volunteers were enrolled into each of three groups based on skin pigmentation history. Subjects were randomized to receive lidocaine/prilocaine cream onto the antecubital fossa of one arm and placebo cream on the comparable location of the other arm for either 60, 90, or 120 minutes prior to venipuncture. Assessments of perceived pain associated with each venipuncture were made by the subject using a visual analog scale. RESULTS: Lidocaine/prilocaine cream applied for 60 minutes significantly (P < .0001) reduced the pain of venipuncture compared to placebo regardless of the skin pigmentation type. Pain reduction did not differ significantly across skin types (P = .7986). Additional exposure up to 120 minutes did not change the efficacy of EMLA cream. CONCLUSIONS: Lidocaine/prilocaine cream is a safe and effective topical anesthetic for reducing pain associated with venipuncture in individuals, regardless of skin pigmentation.

Administration, Topical↗
PubMed1994

Skin pigmentation as a predictor of minimal phototoxic dose after oral methoxsalen.

BACKGROUND AND DESIGN: Twenty-eight subjects were phototested to determine their erythemal responses to oral methoxsalen with UV-A and UV-B irradiation. Skin pigmentation was measured by skin reflectance at 550 and 660 nm before irradiation. The smallest UV radiation dose to produce erythema (minimal phototoxic dose and minimal erythema dose, respectively) was determined. The serum concentration of methoxsalen was measured at the time of UV-A irradiation. RESULTS: There was a positive correlation between skin pigmentation and both 72-hour minimal phototoxic dose and 24-hour minimal erythema dose. No correlation was demonstrated between methoxsalen serum concentration and minimal phototoxic dose. The combination of skin pigmentation and methoxsalen level did not give a better prediction of minimal phototoxic dose than skin pigmentation alone. CONCLUSIONS: Skin pigmentation measurements can be used to predict the minimal phototoxic and erythema doses. Skin pigmentation measurements are easy to perform and should be included in both phototherapy and photochemotherapy to improve the efficiency and reliability of the treatment.

Administration, Oral↗
PubMed2005

Construction of pigmented skin equivalent and its application to the study of congenital disorders of pigmentation.

We have constructed a pigmented skin equivalent and used it to study the hyperpigmentation seen in café-au-lait macules to elucidate whether the pigmented skin equivalent could be used as a model of congenital hyperpigmentary disorders. When we used fibroblasts derived from café-au-lait macules of neurofibromatosis type 1, the amount of pigment was significantly greater than in models using cells derived from normal skin. Quantities of pigment were not seen when keratinocytes derived from solitary café-au-lait macules were used, a possible reason being that keratinocytes on the skin equivalent are in a proliferating condition and are not well-differentiated enough to act on other cells. Our results suggested that our pigmented skin equivalent is useful for the study of congenital hyperpigmentary disorders, although insufficient differentiation of keratinocytes might be a disadvantage.

Cafe-au-Lait Spots↗
PubMed1993

Excision of benign pigmented skin tumours by deep shaving.

Benign pigmented skin tumours are frequently removed by shave excision. There is little information as to how often the method achieves a complete excision of the lesion and how often the full thickness of the dermis is removed. 43 benign pigmented skin tumours, on the trunk and proximal parts of the limbs, were removed by deep shaving and the shaved areas were then removed by elliptical excision. The shave excision achieved complete tumour removal in 72% of the lesions and did not divide the dermis to fat junction in 63%. Both objectives were achieved in 46%. Shave excision of these lesions may be preferable to elliptical excision in sites where the incidence of hypertrophic scarring is high, as preservation of some thickness of the dermis may result in a more acceptable scar.

Adolescent↗
PubMed2006

A scan for signatures of positive selection in candidate loci for skin pigmentation in humans.

Although the combination of pale skin and intense sun exposure results in an important health risk for the individual, it is less clear if at the population level this risk has possessed an evolutionary meaning. In this sense, a number of adaptive hypotheses have been put forward to explain the evolution of human skin pigmentation, such as photoprotection against sun-induced cancer, sexual selection, vitamin D synthesis or photoprotection of photolabile compounds, among others. It is expected that if skin pigmentation is adaptive, we might be able to see the signature of positive selection on some of the genes involved. In order to detect this signature, we analyze a battery of 81 candidate loci by means of phylogenetic and population genetic tests. Our results indicate that both light and dark skin may possess adaptive value. Of the main loci presenting this signature, TP53BP1 shows clear evidence of adaptive selection in Africans, whereas TYRP1 and SLC24A5 show evidence of adaptive selection in Caucasians. Although we cannot offer a mechanism that based on these genes explains the advantage of light skin, if TP53BP1, and perhaps RAD50, have truly conferred an adaptive value to the African population analyzed, photoprotection against sun-induced skin damage/cancer might be proposed as a mechanism that has driven the evolution of human skin pigmentation.

Adaptation, Biological↗