Caucasian Skin Types Research Articles

Using artificial intelligence on dermatology conditions in Uganda: a case for diversity in training data sets for machine learning.

In pursuit of applying universal non-biased Artificial Intelligence (AI) in healthcare, it is essential that data from different geographies are represented. To assess the diagnostic performance of an AI-powered dermatological algorithm called Skin Image Search on Fitzpatrick 6 skin type (dark skin) dermatological conditions. 123 dermatological images selected from a total of 173 images were retrospectively extracted from the electronic database of a Ugandan telehealth company, The Medical Concierge Group (TMCG) after getting their consent. Details of age, gender, and dermatological clinical diagnosis were analysed using R on R studio software to assess the diagnostic accuracy of the AI app along with disease diagnosis and body part. Predictability levels of the AI app were graded on a scale of 0 to 5, where 0- no prediction was made and 1-5 demonstrated a reduction incorrect diagnosis prediction rate of the AI. 76 (62%) of the dermatological images were from females and 47 (38%) from males. Overall diagnostic accuracy of the AI app on black dermatological conditions was low at 17% (21 out of 123 predictable images) compared to 69.9% performance on Caucasian skin type as reported from the training results. There were varying predictability levels correctness i.e., 1-8.9%, 2-2.4%, 3-2.4%, 4-1.6%, 5-1.6% with performance along individual diagnosis highest with dermatitis (80%). There is need for diversity of image datasets used to train dermatology algorithms for AI applications to increase accuracy across skin types and geographies.

A Merkel sejtes karcinóma multimodális kezelési lehetőségei

Merkel cell carcinoma is a rare neuroendocrine skin tumor with an aggressive behavior. The clonal integration of the Merkel cell polyomavirus and the UV light can be highlighted in its pathogenesis. Risk factors for its development are advanced age, chronic UV exposure, caucasian skin type, male gender, and immunosuppression. The disease is prone to rapid progression and the prognosis is unfavorable. In its treatment, surgical removal of the primary tumor and biopsy of the sentinel lymph node, as well as adjuvant radiation therapy, are of particular importance. Among the systemic treatments, immune checkpoint inhibitors are recommended as the first line. The authors discuss the latest European guideline for the diagnosis and the treatment.

Clinical performance of a novel hyperspectral imaging device for cutaneous melanoma and pigmented skin lesions in Caucasian skin.

The quest for diagnostic tools for the detection of cutaneous malignant melanoma (cMM) is ongoing. A challenge in cMM care is not overlooking cMM at an early stage, while simultaneously avoiding unnecessary biopsies or excisions of benign pigmented skin lesions (PSLs). A novel hyperspectral imaging (HSI) device is shown to have potential for differentiating equivocal PSLs in Asian skin types. Our objective was to assess the accuracy of the HSI device in distinguishing between cMM and benign PSLs in patients with Caucasian skin types. Patients with Caucasian skin types (Fitzpatrick I-II), enrolled for excisional biopsies of PSLs were included and examined using the HSI device. The discrimination index (DI) was used to demonstrate the sensitivity (SE) and specificity (SP) in comparison with the re-evaluated histopathology diagnoses. In 186 patients, 202 pigmented skin lesions were included. The sensitivity to detect cMM was 96.7% (87/90), and the specificity for benign lesions was 42.1% (45/107). The AUC was 0.800 (95% confidence interval (CI): 0.740-0.861). Our novel HSI device showed a high sensitivity in detecting malignant lesions in patients with Caucasian skin types. Compared with analogous technologies, as multispectral imaging or electrical impedance spectroscopy, our device showed similar or better accuracy in differentiating cMM from benign PSLs. Therefore, it might be a useful clinical tool in skin types I-IV and where further triage of pigmented skin lesions is important.

Reconstructed Skin Models Revealed Unexpected Differences in Epidermal African and Caucasian Skin

Clinical observations of both normal and pathological skin have shown that there is a heterogeneity based on the skin origin type. Beside external factors, intrinsic differences in skin cells could be a central element to determine skin types. This study aimed to understand the in vitro behaviour of epidermal cells of African and Caucasian skin types in the context of 3D reconstructed skin. Full-thickness skin models were constructed with site matched human keratinocytes and papillary fibroblasts to investigate potential skin type related differences. We report that reconstructed skin epidermis exhibited remarkable differences regarding stratification and differentiation according to skin types, as demonstrated by histological appearance, gene expression analysed by DNA microarray and quantitative proteomic analysis. Signalling pathways and processes related to terminal differentiation and lipid/ceramide metabolism were up-regulated in epidermis constructed with keratinocytes from Caucasian skin type when compared to that of keratinocytes from African skin type. Specifically, the expression of proteins involved in the processing of filaggrins was found different between skin models. Overall, we show unexpected differences in epidermal morphogenesis and differentiation between keratinocytes of Caucasian and African skin types in in vitro reconstructed skin containing papillary fibroblasts that could explain the differences in ethnic related skin behaviour.

Merkel cell carcinoma incidence is increasing in Sweden.

Merkel cell carcinoma (MCC) is a rare aggressive neuroectodermal skin cancer with a high recurrence rate and a high mortality rate. Risk factors for MCC are reported to include high age, UV exposure, Caucasian skin type and immunosuppression. The incidence is reported to be increasing. The purpose of this study was to describe a Swedish cohort and calculate incidence. The study design is a retrospective cohort study of population-based data for MCC collected by the Swedish Cancer Registry to determine the incidence of MCC in Sweden and the clinical characteristics of these tumours including demographics, TNM classification, body part distribution and overall survival after diagnosis. De-identified data were collected from 1993 to 2012. A total of 606 cases of MCC were identified during the study period. The median age was 81years (range 21-99) and a majority, 54.4% were women but age-adjusted incidence is higher in men. The incidence (per 100,000) of MCC in Sweden in 1993-2012 increased from 0.09 to 0.20 for men and 0.12-0.17 for women, adjusted for age to the world standard population. For the both sexes, the increase was from 0.11 to 0.19 per 100000, an increase of 73%. The most common site of the primary tumour was the head and neck, with 51.8% of the cases. The size of the tumour was <5cm in 82.1% of the cases. The majority of the tumours (90.7%) had no known lymphatic spread and only a few patients had confirmed distant metastases (2.9%) when diagnosed. MCC is a rare disease in Sweden, but the incidence is increasing. This study supports the finding that high age, male sex and UV exposure are risk factors for MCCs. Interventions are required to increase awareness of MCC among clinicians and the public.

Validation of a Questionnaire to Diagnose the Baumann Skin Type in All Ethnicities and in Various Geographic Locations

The Baumann Skin Typing System diagnoses patients as having one of 16 skin types based on their answers to a validated questionnaire [i] known as the Baumann Skin Type Indicator [ii]. The BSTI questionnaire has been tested over the last decade on over 200,000 people of various ages and ethnicities in different geographic locations around the world. In this study, data were collected from 52,862 patients to compare skin type prevalence between those who presented to doctor’s offices and those who took the quiz without supervision online. The most common skin types varied only slightly between patients that took the quiz online and those that completed the questionnaire in their doctor’s office. This indicates that the prevalence of skin types seen in the doctor’s office is similar to that in the general population and that supervision is not necessary to get an accurate result on the BSTI. [iii] In addition, comparison of data gathered in China, Korea, and the US did not show a significant difference in skin type prevalence between Asian and Caucasian skin types. [iv] This study demonstrates that the English version of the BSTI is valid for English speaking patients online, and in doctors’ offices in the US, China and Korea.

In vivo and in vitro approaches in understanding the differences between Caucasian and African skin types: specific involvement of the papillary dermis

Most of the identified differences between Caucasian and African skin types have been related to the superficial part of the skin, the epidermis. We investigated possible implications of the dermal compartment in cutaneous differences observed between Caucasians and Africans. In vivo and in vitro comparative studies were carried out using normal human skin biopsies and the corresponding in vitro reconstructed skin. Skin equivalents were developed with papillary fibroblasts isolated from the superficial dermis of both Caucasian and African skin types. Expression of major components of the dermal-epidermal junction (DEJ) was examined as a function of ethnicity. Control histological examinations of skin biopsies showed that the African skin type had greater convoluted appearance of the DEJ than the Caucasian skin type. Immunostainings of type IV and VII collagens, laminin 5, and nidogen proteins at the DEJ were lower in African skin compared with Caucasian skin biopsies. This study brings together new elements on involvement of the papillary dermis in differences between Caucasian and African skin types. As fibroblasts from the superficial dermis cooperate with epidermal keratinocytes in producing protein of the membrane basal zone, present in vivo results suggest that papillary fibroblasts may play a part in the distinct features observed at the DEJ. In preliminary in vitro experiments, differences in several protein expressions contributing to the DEJ framework were found in reconstructed skin models made with papillary fibroblasts from both Caucasian and African skin types. Therefore, in vitro skin equivalents may be useful for better understanding of ethnic skin differences in the future.

Fractional Ablative Radio-Frequency Resurfacing in Asian and Caucasian Skin: A Novel Method for Deep Radiofrequency Fractional Skin Rejuvenation

This paper reports the clinical experience of a multi-center, multiple physician trial with a novel fractional radiofrequency ablative skin resurfacing and rejuvenation device (Fractora, Invasix, Israel) deployed on both Caucasian skin types I - III and Asian skin type IV. Histological study demonstrated deep ablation and collagen restructuring in the papillary and reticular dermis. The Fractora device combines the more “cone shaped” ablation seen with CO2 and Erbium lasers with a deep non-ablative heating pattern, seen with other bipolar RF fractional needle resurfacing devices. Ablation, coagulation zones and healing dynamics are analyzed for different energy settings. Two different treatment protocols are suggested: one for light skin and then one for darker skin with a higher risk of post-inflammatory hypperpigmentation. Treatment results show improvement in skin texture, pores, wrinkles and skin dyschromia.

Regulation of the Catalytic Activity of Preexisting Tyrosinase in Black and Caucasian Human Melanocyte Cell Cultures

The activity of tyrosinase, the rate-limiting enzyme for melanin synthesis, is higher in Black skin melanocytes than in melanocytes derived from Caucasian skin. This variation in enzyme activity is not due to differences in tyrosinase abundance or tyrosinase gene activity, but, rather, is due to differences in the catalytic activity of preexisting tyrosinase. In melanocytes, tyrosinase is localized to the membrane of melanosomes and in Caucasian melanocytes the melanosome-bound enzyme is largely inactive. Conversely, in melanosomes of Black melanocytes, tyrosinase has high catalytic activity. Treatment of Caucasian melanocytes with the lysosomotropic compound ammonium chloride or with the ionophores nigericin and monensin results in a rapid and pronounced increase in tyrosinase activity. This increase occurs without any change in tyrosinase abundance, indicating that these compounds are increasing the catalytic activity of preexisting enzyme. Inhibition of the vacuolar proton pump V-ATPase by treatment of Caucasian melanocytes with bafilomycin also increases tyrosinase activity. In contrast to the 10-fold increase in tyrosinase observed in Caucasian melanocytes, neither ammonium chloride, monensin, nigericin, nor bafilomycin is able to increase the already high level of tyrosinase activity present in melanosomes of melanocytes derived from Black skin. Finally, staining of Caucasian melanocytes with the fluorescent weak base acridine orange shows that melanosomes of Caucasian, but not Black, melanocytes are acidic organelles. These data support a model for racial pigmentation that is based on differences in melanosome pH in Black and Caucasian skin types. The models suggests that melanosomes of Caucasian melanocytes are acidic, while those of Black individuals are more neutral. Since tyrosinase is inactive in an acid environment, the enzyme is largely inactive in Caucasian melanosomes but fully active in Black melanosomes.

Laser Resurfacing in Pigmented Skin

Laser skin resurfacing is a very promising new treatment for solar elastosis and acne scars. The Ultrapulse carbon dioxide (CO2) laser and the SilkTouch flashscanner allow precise depth control and char-free ablation. Earlier studies have been done mainly on Caucasian skin types I and II, but very little data were available on pigmented skin. The purpose of this study is to assess the efficacy and safety of laser skin resurfacing in skin types III and IV. Thirty Asian and Hispanic patients were treated for facial rhytides and acne scars. All patients were instructed to use tretinoin cream 0.05%, hydroquinone 5%, and desonide 0.1% cream nightly for 2-4 weeks prior to the laser treatment. The Ultrapulse 5000C CO2 laser with the Truespot 3-mm collimated handpiece at the setting of 250-450 mJ per pulse, or the Silk-Touch flashscanner at the setting of 5-7 W, 0.2-second pulse duration, and 4-mm (M) spot size, was used. Patients were evaluated clinically, and global response was assessed by both clinicians and patients. The facial rhytides and acne scars improved 25-50% in all patients after one laser treatment. The most common side effects were persistent erythema that resolved on the average of 6 weeks. Hyperpigmentation occurred, but was reduced with regular use of tretinoin, hydroquinone, and desonide cream both pre- and postoperatively along with use of broad spectrum sunscreen after treatments. Laser skin resurfacing can be used to treat facial rhytides and acne scars in skin phototypes III and IV. When proper pre- and postoperative management is implemented, the risk of dyspigmentation can be reduced.