Narrow-band Reflectance Spectrophotometer Research Articles

Improvement of Nonlesional Skin Tone and Skin Barrier in Severe Atopic Dermatitis after Dupilumab Treatment

Dupilumab, approved for the treatment of moderate-to-severe atopic dermatitis (AD), has been proven to improve skin barrier and postinflammatory hyperpigmentation on nonlesional areas. Previous studies, however, are only based on subjective visual assessments rather than objective biophysical measurements. We aimed to objectively measure transepidermal water loss (TEWL) and skin tone improvements after dupilumab treatment through bioengineering devices. Nineteen patients with severe AD were enrolled. Biophysical measurements were conducted in three nonlesional skin areas, the cheek, forearm, and lower abdomen, on a monthly basis for 5 months since the first dupilumab injection. TEWL was measured using a Tewameter®. Skin tones represented by L ∗ (lightness), a ∗ (redness), and b ∗ (yellowness) parameters were measured by the spectrophotometer®; the erythema and melanin index measured by the narrow-band reflectance spectrophotometer® were additionally assessed. Improvement from baseline was evaluated by the Wilcoxon’s rank-sum test and Bonferroni correction. Correlation among biophysical parameters was evaluated by Pearson’s correlation. p < 0.05 was considered statistically significant. TEWL and skin tone parameters in all anatomical regions showed significant improvement. The L ∗ and a ∗ values of the arm and trunk significantly improved after 2 months of dupilumab therapy and the face 3 months after. Similarly, b ∗ value of all anatomical regions significantly decreased after 1 month of treatment, and the TEWL did so after 2 months. When compared between anatomic regions, the trunk demonstrated higher improvement in L ∗ value, the arm in erythema index, and the face in melanin index. TEWL positively correlated with erythema index (r = 0.51, p < 0.05), melanin index (r = 0.45, p < 0.05), and a ∗ (r = 0.50, p < 0.05); negative correlation was observed with L ∗ (r = −0.48, p < 0.05). On top of AD symptom relief, dupilumab objectively improves the skin barrier and skin tone of nonlesional areas.

Correlation between Acanthosis Nigricans Scoring Chart (ANSC) and narrowband reflectance spectrophotometer in assessing severity of acanthosis nigricans.

There is a lack of standardized tool to monitor treatment outcome of acanthosis nigricans. To meet this end, we developed the Acanthosis Nigricans Scoring Chart (ANSC) that evaluates skin color (score range of 1-8) and skin texture (score range of 1-6), which adds up to a total ANSC score (score range of 2-14). We aimed to determine the correlation of ANSC to narrowband reflectance spectrophotometry and to evaluate its reliability. A cross-sectional study was conducted in adult acanthosis nigricans patients. Two raters independently graded participants using ANSC twice, in which scores were correlated to readings from Mexameter MX18. Intra- and interrater reliability were also evaluated via intraclass correlation coefficient (ICC). Participants had mean (sd) melanin and erythema indices of 615.8 (176.2) and 451.4 (53.4), respectively. Mean (sd) total ANSC score was 9.43 (2.43). The total ANSC score and skin color subdomain demonstrated strong correlations (r>0.6) with spectrophotometric results, whereas skin texture showed a moderate correlation (r=0.4-0.6). Total ANSC score generally had excellent intra- and interrater reliabilities (ICC>0.85). The total ANSC score and its subdomains strongly correlate with spectrophotometer and demonstrate excellent reliability in assessing acanthosis nigricans.

A comparison of the efficacy and safety profiles of 10% salicylic acid and 10% urea creams in treating acanthosis nigricans in adolescents: a randomized double-blinded study.

Acanthosis nigricans is characterized by the presence of velvety hyperpigmentation of the skin over the neck and the flexural areas. Regardless of different modalities of treatment, none provides a definite standard cure. This study aims to assess the efficacy of topical 10% salicylic acid compared to 10% urea cream in treating acanthosis nigricans in adolescents. A randomized comparative, double-blind study is conducted on adolescents with acanthosis nigricans of the posterior neck. Treatment efficacy was assessed via a narrowband reflectance spectrophotometer at individual follow-up visits at weeks 2, 4, and 8, while the overall success rates were evaluated by the investigator-assessed and participant-assessed global evaluation scales (IGE and PGE). Acanthosis nigricans scoring chart (ANSC) and adverse effects are also assessed. A total of 39 participants with acanthosis nigricans enrolled and completed the study. Throughout the 8-week period of treatment, the use of 10% salicylic acid demonstrated strong effectiveness in treatment with 14.6 ± 10.6% improvement, while the 10% urea demonstrated 12.5 ± 10.9% improvement. Findings from the overall global evaluation scales were consistent with the results from the narrowband reflectance spectrophotometer. Treatment with 10% salicylic and 10% urea produced no serious local skin adverse reactions. Both medications improve neck hyperpigmentation associated with acanthosis nigricans in adolescents, in which the 10% salicylic acid and 10% urea cream demonstrate similar efficacy and safety profiles. Clinical Trials Registry: TCTR20201123003.

Reliability assessment and validation of the post-acne hyperpigmentation index (PAHPI) in a population from Sub-Saharan Africa in Senegal

BackgroundA post-acne hyperpigmentation index (PAHPI) has been developed in the United States to better compare therapeutic modalities. Our aim in this study was to validate the PAHPI score in patients with skin type VI from sub-Saharan Africa. Patients and methodsThe study was conducted in Dakar, Senegal. Twenty-one patients with Fitzpatrick skin type VI, aged 17 to 55 years, presenting hyperpigmentation secondary to acne were included. Ongoing use of skin bleaching products or acne treatments was allowed. Four trained dermatologists rated the patients using the PAHPI. A narrow-band reflectance spectrophotometer (Mexameter MX-18, Cologne, Germany) was used to measure the degree of pigmentation of involved and adjacent skin on 6 representative facial lesions. ResultsThe average inter-rater reliability (weighted Kappa) showed substantial agreement for intensity (0.67), moderate agreement for number (0.53) and fair agreement for lesion size (0.28). Inter-rater reliability for the total PAHPI was excellent for both day 1 and day 2 (interclass correlation coefficient of 0.87 and 0.85, respectively; P<0.0001). Intra-rater reliability for total PAHPI ranged from 0.83 to 0.93 (P<0.0001). PAHPI scoring thus demonstrated excellent reliability both between and within raters. The association was moderate to substantial for all raters on both days (range for rho on day 1: 0.531 to 0.815; range for rho on day 2: 0.448 0.762). The correlations between the Mexameter (Courage and Khazaka) measurements and PAHPI scores showed moderate to substantial agreement. ConclusionAlthough tested primarily in African American women to date, PAHPI is also valid for patients from sub-Saharan Africa.

The efficacy and safety of 20% urea cream and 10% urea cream in the treatment of acanthosis nigricans in adolescents, arandomized comparative double-blind study.

Acanthosis nigricans is commonly associated with obesity. It is characterized by brown-black skin thickening on the neck and the flexural areas. This study aimed to assess the efficacy of topical 20% urea cream compared to 10% urea cream in the treatment of acanthosis nigricans in adolescents. A randomized comparative, double-blind study was conducted on participants aged 12-18years with acanthosis nigricans of the neck. Treatment efficacy was assessed via narrowband reflectance spectrophotometer, while the overall success rates at weeks 2, 4, and 8 were evaluated by the investigator- and participant-assessed global evaluation scales. A total of 40 participants with acanthosis nigricans were enrolled and completed the study. Throughout the period of 8weeks of treatment, 20% urea showed greater improvement of hyperpigmentation compared to 10% urea (p=0.001), with 22.5±11.9% and 10.7±8.1% improvements, respectively. Findings from the overall global evaluation scales were consistent with the results from the narrowband reflectance spectrophotometer. Treatment with 10% urea and 20% urea was well-tolerated without any local serious adverse reactions. Urea cream improves neck hyperpigmentation associated with acanthosis nigricans in adolescents, in which the 20% concentration shows superior efficacy to the 10% concentration.

Skin colour, skin redness and melanin biometric measurements: comparison study between Antera® 3D, Mexameter® and Colorimeter®

The actual skin colorimeters analyse reflect values from a limited number of broad spectral bands and consequently present limited reproducibility and specificity when measuring skin colour. Here, Antera 3D(®) , a new device which uses reflectance mapping of seven different light wavelengths spanning the entire visible spectrum, has been compared with Mexameter(®) MX-18, an established narrow-band reflectance spectrophotometer and with Colorimeter(®) CL-400, an established tristimulus colorimetric instrument. Thirty volunteers were exposed to a controlled ultra-violet B light. Measurements with Antera 3D(®) , Mexameter(®) MX-18 and Colorimeter(®) CL-400 were done before treatment and after 2, 7 and 14days. Antera 3D(®) showed to have a better sensitivity and specificity than Mexameter(®) MX-18 regarding the melanin parameter. A similar sensitivity between Antera 3D(®) and Mexameter(®) MX-18 was found for erythema determination and also for the Commission Internationale de l'Eclairage L*, a* and b* parameters between Antera 3D(®) and Colorimeter(®) CL-400. Good correlations were observed for all the parameters analysed. Repeatability of Mexameter(®) MX-18 and Colorimeter(®) CL-400 values were lower than that of Antera 3D(®) for all the parameters analysed. Antera 3D(®) , such as Mexameter(®) MX-18 and Colorimeter(®) CL-400, are robust, sensitive and precise equipment for the skin colour analysis.

Triple combination as adjuvant to cryotherapy in the treatment of solar lentigines: investigator‐blinded, randomized clinical trial

Post-inflammatory hyperpigmentation is a frequent concern when treating solar lentigines. To assess the safety and efficacy of a triple combination cream with fluocinolone acetonide 0.01%, hydroquinone 4% and tretinoin 0.05% as adjuvant to cryotherapy in the treatment of solar lentigines in hands dorsum, and in the prevention of post-inflammatory hyperpigmentation after cryotherapy. This prospective, randomized, controlled, investigator-blinded, single-centre study enrolled 50 patients. Twenty-five patients received a 2-week daily triple combination cream plus sunscreen pre-treatment and 25 received sunscreen alone. After that, cryotherapy was performed in all patients followed by a 3-week recovery period. After this period, patients received the same initial treatment and were followed up for 8weeks. Melanin and erythema levels of a target and a control lentigo were objectively measured using a narrowband reflectance spectrophotometer. Lentigines count, colour homogeneity and global improvement were also assessed. The number of solar lentigines reduced in the first 2weeks only in patients who used the triple combination 25±7 vs. 22±8 (P<0.0001), and reduced at the end of the study for both groups (P<0.0001). The melanin levels also reduced in the first 2weeks only in patients who used the triple combination 297±69 vs. 273±66 (P<0.0001) and reduced at the end of the study for both groups (P<0.0001). Erythema and residual blisters from cryotherapy were the reported adverse reactions. Triple combination cream can be used to enhance the resolution of solar lentigines, and to significantly reduce melanin levels and lentigines count, improving treatment results. It was well-tolerated and did not increase the occurrence of neither erythema nor other side-effects after the cryotherapy.

Correlation between skin color evaluation by skin color scale chart and narrowband reflectance spectrophotometer.

Context:Various methods are available for the evaluation of skin color. A skin color scale chart is a convenient and inexpensive tool. However, the correlation between a skin color scale chart and objective measurement has not been evaluated.Aims:To assess the correlation between skin color evaluation done by a skin color scale chart (Felix von Luschan skin color chart) and a narrowband reflectance spectrophotometer (Mexameter MX18).Materials and Methods:The participants were evaluated for skin color by using the Felix von Luschan skin color chart (range 1-36) and a narrowband reflectance spectrophotometer (Mexameter MX18) in which the results of the measurements were expressed as Erythema (E) and Melanin (M) indices. Skin color was measured on four different anatomical skin sites from each participant on the medial aspect of the volar and the dorsal regions of both forearms. Results: A total of 208 records from 52 participants were established. The majority of participants (19.2%) were rated with the skin color scale at the number 16 (range 14-33). The mean M plus E, M, and E indices were 498.9 ± 143.9, 230.4 ± 74.4, and 268.5 ± 73.2, respectively. The correlation coefficient between the number on the skin color scale and each index: M plus E, M, and E indices were 0.90, 0.90, and 0.86, respectively, with a statistical significance of P < 0.001.Conclusions:Skin color evaluation using a skin color scale chart has shown a high correlation with skin color evaluation done by the narrowband reflectance spectrophotometer.

Reliability assessment and validation of the postacne hyperpigmentation index (PAHPI), a new instrument to measure postinflammatory hyperpigmentation from acne vulgaris

There are no validated outcome measures for postinflammatory hyperpigmentation (PIH). We sought to determine the reliability and validity of an outcome measure for PIH after acne in patients with skin of color. A postacne hyperpigmentation index (PAHPI) was developed. Six raters scored 21 patients with PIH twice. Reliability was determined within and between raters, whereas validity was evaluated by comparing scores with severity ranking by an independent dermatologist. The pigment intensity scores were compared with the melanin index of each patient using a narrowband reflectance spectrophotometer. A quality-of-life score (Skindex-29) was also compared with PAHPI scores. Total PAHPI scores showed good reliability within and between raters and were valid when compared with clinical severity and melanin indices. Good correlation was achieved between the total PAHPI score and the emotion subscale of the Skindex-29. Generalizability of results is limited to African American females. The PAHPI shows good reliability and validity when scored on patients with PIH from acne vulgaris. The PAHPI also correlates well with the emotional impact of PIH as measured by the Skindex-29. Future studies should assess the ability of the PAHPI to change with improvement of PIH from acne after treatment.

Treatment of Infraorbital Dark Circles Using a Low-Fluence Q-Switched 1,064-nm Laser

OBJECTIVE To evaluate the efficacy and safety of the low-fluence 1,064-nm Q-switched neodymium-doped yttrium aluminium garnet (QSNY) laser in treating infraorbital dark circles. PARTICIPANTS AND METHODS Thirty women with infraorbital dark circles (predominant color dark brown) participated in this open-label study. Participants underwent eight sessions of low-fluence QSNY laser treatment at 4.2 J/cm2 at 3- to 4-day intervals. A spot size of 3.5 mm was used, with a pulse duration of 8 ns. The melanin deposition in the lesional skin was observed in vivo using reflectance confocal microscopy (RCM). Morphologic changes were evaluated using a global evaluation, an overall self-assessment, a narrow-band reflectance spectrophotometer, and a skin hydration measurement instrument. RESULTS Twenty-six of 30 patients showed global improvement that they rated as excellent or good. Twenty-eight rated their overall satisfaction as excellent or good. The melanin index indicated a substantial decrease, from 225.84 at baseline to 182.65 (p<.05). RCM results showed a dramatic decrease of melanin deposition in the upper dermis. Adverse effects were minimal. CONCLUSIONS The characteristic finding for dark-brown infraorbital dark circles is melanin deposition in the upper dermis. Treatment of infraorbital dark circles using low-fluence 1,064-nm QSNY laser is safe and effective. The authors have indicated no significant interest with commercial supporters.

Treatment of Infraorbital Dark Circles Using a Low-Fluence Q-Switched 1,064-nm Laser

To evaluate the efficacy and safety of the low-fluence 1,064-nm Q-switched neodymium-doped yttrium aluminium garnet (QSNY) laser in treating infraorbital dark circles. Thirty women with infraorbital dark circles (predominant color dark brown) participated in this open-label study. Participants underwent eight sessions of low-fluence QSNY laser treatment at 4.2 J/cm(2) at 3- to 4-day intervals. A spot size of 3.5 mm was used, with a pulse duration of 8 ns. The melanin deposition in the lesional skin was observed in vivo using reflectance confocal microscopy (RCM). Morphologic changes were evaluated using a global evaluation, an overall self-assessment, a narrow-band reflectance spectrophotometer, and a skin hydration measurement instrument. Twenty-six of 30 patients showed global improvement that they rated as excellent or good. Twenty-eight rated their overall satisfaction as excellent or good. The melanin index indicated a substantial decrease, from 225.84 at baseline to 182.65 (p < .05). RCM results showed a dramatic decrease of melanin deposition in the upper dermis. Adverse effects were minimal. The characteristic finding for dark-brown infraorbital dark circles is melanin deposition in the upper dermis. Treatment of infraorbital dark circles using low-fluence 1,064-nm QSNY laser is safe and effective. The authors have indicated no significant interest with commercial supporters.

The impact of dialysis modality on skin hyperpigmentation in haemodialysis patients

Skin hyperpigmentation in end-stage renal disease (ESRD) patients has been attributed to the accumulation of middle-molecular-weight (MMW) substances. Although an MMW mechanism suggests that hyperpigmentation may be improved by high-flux haemodialysis (HF-HD) and haemodiafiltration (HDF), this possibility has not been explored. In the present study, we investigated the impact of different dialysis modalities on skin colour in HD patients. Eighty-two ESRD patients on HD were divided into low-flux HD (LF-HD), HF-HD and HDF groups. The melanin index (MI) and erythema index (EI) of the abdomen and the flexor side of the forearm (non-sun-exposed areas) and the forehead (sun-exposed area) were determined by using a narrow-band reflectance spectrophotometer at baseline and after 12 months. Even though absolute values of baseline and follow-up MI and EI of the three sites were comparable among the three groups, forehead MI and EI were significantly decreased after 12 months in the HDF group (P < 0.05). In addition, the change in forehead MI was significantly greater in the HDF than in the LF-HD group (-1.0 +/- 2.4% versus 0.3 +/- 1.6%, P < 0.05). Moreover, beta(2)-microglobulin reduction rates were negatively correlated with both changes in forehead MI (P < 0.01) and EI (P < 0.05). Skin colour of sun-exposed areas was signi- ficantly decreased in ESRD patients receiving HDF therapy, suggesting that enhanced removal of MMW substances by convection may prevent or reduce hyperpigmentation in HD patients.

Usefulness of a narrow-band reflectance spectrophotometer in evaluating effects of depigmenting treatment.

As a depigmenting treatment, combined topical applications of all-trans retinoic acid (atRA) aqueous gel and 5% hydroquinone, 7% lactic acid ointment were used for Oriental patients with hyperpigmented skin lesions such as senile lentigines and nevus spilus. A narrow-band reflectance spectrophotometer and a tristimulus colorimeter were used to evaluate objectively the intensity of pigmentation and erythema at each clinical visit. L*, a*, and b* values measured with a tristimulus colorimeter (Chroma Meter CR-300) enabled the evaluation of erythema but not pigmentation. On the other hand, the melanin and hemoglobin values measured with a narrow-band reflectance spectrophotometer (Mexameter MX-16) expressed both erythema and pigmentation well. It was revealed that, in our bleaching protocol, the narrow-band reflectance spectrophotometer was quite useful for estimating accurately the intensity of pigmentation and erythema and determining the best time point for the cessation of atRA treatment.

Topographic measurement of skin color by narrow-band reflectance spectrophotometer and minimal erythema dose (MED) in Koreans.

Narrow-band reflectance spectrophotometer is one of the objective and quantitative devices for measuring the skin colors. There has been some controversy concerning the relationship between the objectively measured skin color and cutaneous responsiveness to ultraviolet radiation, including minimal erythema dose (MED). The aims of this study were to compare the color of Korean brown skin with that of Caucasians by objective measurement with the narrow-band reflectance spectrophotometer, and to determine whether the skin color has any correlation with MED in Koreans, and demonstrate differences in this correlation according to the anatomical sites. With narrow-band reflectance spectrometer, skin colors were measured at 17 body sites of 20 healthy Korean male volunteers after measuring MED for the same subjects. The constitutional skin color, as measured by the melanin index of the nonexposed sites, showed a statistically significant correlation with MED values, whereas the facultative skin color did not. The Korean brown skin showed higher melanin index and lower erythema index compared with that of Caucasians. We confirmed significant differences in the correlation between MED and melanin indices, depending on the anatomic sites. This suggests that selection from various sites, even among the nonexposed sites, is quite important and deserves further evaluation.

Measurement of color parameters of psoriatic plaques by narrow-band reflectance spectrophotometry and tristimulus colorimetry.

Color parameters were measured on 50 psoriatic plaques in 10 patients, after scoring the amount of scales on them by inspection, with a narrow-band reflectance spectrophotometer (erythema/melanin index expression) and tristimulus colorimeter (CIE L*a*b* expression). Both erythema index a* (redness) were highest in the group of erythematous plaque with little scale (twice as high as in controls) and decreased significantly as the plaques were covered with thicker scale, while L* (brightness) changed in just the opposite fashion of a*. These portable 'color indicators' can be utilized to express the appearance of psoriatic plaques quantitatively, especially the extent of erythema and the amount of the scale on it.