Comparison between visual score and erythema index (DermaSpectrometer) in evaluation of allergic patch tests

Skin erythema assessment techniques

Skin erythema may present owing to many causes. One of the common causes is prolonged exposure to sunrays. Other than sun exposure, skin erythema is an accompanying sign of dermatologic diseases, such as psoriasis and acne. Quantifying skin erythema in patients enables the dermatologist to assess the patient's skin health. Quantitative assessment of skin erythema has been the focus of several studies. The clinical standard for erythema evaluation is visual assessment; however, this standard has some deficiencies. For instance, visual assessment is subjective and ineffectual for precise color information exchange. To overcome these limitations, in the past three decades various methodologies have been developed in an attempt to achieve objective erythema assessments, such as diffuse reflectance spectroscopy and both optical and nonoptical systems. This review considers the studies published during the past three decades and discusses the performance, the mathematical tactics for computation, and the limited capabilities of erythema assessment techniques for cutaneous diseases. The achievements and limitations of the current techniques in erythema assessment are presented. The advantages and development trends of optical and nonoptical methods are presented to make the reader aware of the present technological advances and their potential for dermatological disease research.

The 21-day cumulative irritation assay in man: a half-century summary and re-evaluation

The 21-day cumulative irritation test (21-day CIT) has been widely used in dermatopharmacology and dermatotoxicology to assess the irritation potential of topical products. Since described by Lanman in 1968, it has been modified, shortened, re-evaluated, and statistically analysed by multiple groups of authors. As the assay has been recommended in FDA draft guidance, we bring subsequent experience to date. The shorter 14-day version is commonly used and may be as adequate as the 21-day application when used to discriminate between moderate to strong irritants. While previous authors stopped the test when subjects experienced an irritation score of 3 or more, the FDA suggested moving the test to another anatomical site to complete in 21 days. This approach avoids assumptions, thus may be more accurate to quantify skin irritation. As the scoring is based on visual grading, the 21-day CIT also does not account for sensory irritation. Therefore, future studies need to propose a way to evaluate the sensation objectively in dermatological product development.

Skin erythema and pigmentation: a review of optical assessment techniques

BACKGROUND

Skin erythema may present due to many causes. One of the common causes is prolonged exposure to sun rays. Other than sun exposure, skin erythema is an accompanying sign of dermatological diseases such as acne, psoriasis, melasma, post inflammatory hyperpigmentation, fever, as well as exposure to specific electromagnetic wave bands.

METHODS

Quantifying skin erythema in patients enables the dermatologist to assess the patient's skin health. Therefore, quantitative assessment of skin erythema was the target of several studies. The clinical standard for erythema evaluation is visual assessment. However, the former standard has some imperfections. For instance, it is subjective, and unqualified for precise color information exchange. To overcome these shortcomings, the past three decades witnessed various methodologies that aimed to achieve erythema objective assessment, such as diffuse reflectance spectroscopy (DRS), and both optical and non-optical systems.

DISCUSSION

This review article reports on the studies published in the past three decades where the performance, the mathematical tactics for computation, and the capabilities of erythema assessment techniques for cutaneous diseases are discussed. In particular, the achievements and limitations of the current techniques in erythema assessment are presented.

CONCLUSION

The profits and development trends of optical and non-optical methods are displayed to provide the researcher with awareness into the present technological advances and its potential for dermatological diseases research.

Prevalence of melanocytic nevi in 8- to 10-year-old children in Southern Spain and analysis of associated factors

BACKGROUND

There is a known relationship between melanocytic nevi (MN) and cutaneous melanoma. MN are related to genetic and environmental factors, and the latter appear to be more important in childhood.

OBJECTIVES

To determine the prevalence of MN and its relationship with phenotypic traits and sun exposure habits in 8- to 10-year-old children.

SUBJECTS AND METHODS

We performed a cross-sectional study of 8- to 10-year-old primary school children in the city of Granada (Spain), gathering data on phenotypic traits, sun protection measures, sunburn frequency and the number and density of MN.

RESULTS

We detected a mean of 19.38 MN per child, predominantly <2 mm in diameter. MN count was associated with low phototype, and was higher in boys vs. girls with low phototype. MN were more numerous with higher age. The largest number of MN of all sizes was detected in 10-year-old boys. MN were most frequently located on the torso and other sites intermittently exposed to sunlight.

CONCLUSIONS

A higher MN count is associated with lower phototype (blonde hair and fair skin) and higher age. The mean number of MN, including those of smaller size (<2 mm), was elevated in our series, especially on intermittently exposed sites.

Influence of a detergent on skin response to methyldibromo glutaronitrile in sensitized individuals

The present study was undertaken to evaluate the combined effect of the preservative methyldibromo glutaronitrile (MDBGN) and sodium lauryl sulfate (SLS) on the elicitation response of allergic contact dermatitis. 20 volunteers with contact allergy to MDBGN were patch tested with 5 concentrations (10, 50, 100, 500 and 1000 p.p.m.) of MDBGN alone and in combination with 0.25% SLS on the upper arms for 24 h. Skin reactions were evaluated by clinical scoring, and data were evaluated by logistic dose-response models. Additionally, evaluation of skin reactions was performed by measurement of transepidermal water loss (TEWL) and skin colour. Measurements were obtained at baseline and at D3 and D7. As evaluated by clinical assessment, allergic reactions to MDBGN were elicited at lower concentrations when applied in combination with SLS than when applied alone. The response was augmented by a factor of 6.4. An increased response to combined exposure to SLS and MDBGN as compared with MDBGN alone was confirmed by TEWL and colour measurements. Effects of exposure time and concentration of the detergent are discussed. In conclusion, an augmented response was found after concurrent application of MDBGN and SLS. The response was augmented by a factor of 6.4, with confidence limits of 2.8-14.6 (P < 0.0001). This result is important in relation to the determination of threshold values and the risk assessment of contact allergens in consumer and industrial products, where allergens are often present in combination with surfactants.

Combined effects of irritants and allergens. Synergistic effects of nickel and sodium lauryl sulfate in nickel- sensitized individuals

Knowledge of the combined effects of irritants and allergens is of interest with respect to accurate risk assessment. The threshold for elicitation of allergic contact dermatitis in previously sensitized individuals may theoretically be markedly influenced by the simultaneous presence of irritants and allergens. Combined exposures have, however, only been studied infrequently. In the present study, the combined effect of an irritant and an allergen was evaluated in a dose-response designed experimental study. 20 nickel-sensitized subjects were exposed to patch testing with varying concentrations of NiCl2 (nickel chloride) and sodium lauryl sulfate (SLS) alone and in combination. Evaluation of skin reactions was performed by colorimetry, measurement of transepidermal water loss and clinical evaluation, and the data were analyzed by logistic dose-response models. A synergistic effect was found of combined exposure to NiCl2 and SLS, as compared to each of the substances applied separately, as evaluated by colorimetry and clinical scoring. This means that the effect produced by the combined exposure was substantially greater than the effect produced by either of the substances alone. A synergistic effect of combined exposure on skin barrier impairment was not found, since the barrier function is significantly influenced by SLS-exposure only and not by NiCl2. Concentration limits are used by industry and government agencies to protect consumers. The present results clearly illustrate that elicitation thresholds and concentration limits may be influenced considerably by combined exposure to allergens and irritants.

Quantification of erythema using digital camera and computer-based colour image analysis: a multicentre study

BACKGROUND/PURPOSE

Colour measurements obtained from digitized images have been proposed as a simple and cost-effective way to evaluate skin colour and the activity of treatments. The main disadvantage of the method is the fact that it is highly dependent on ambient light: even if an accurate control of subjects' illumination is provided, readings remain not comparable among different laboratories. The purpose of this study was to develop a highly reproducible system for computerized colour image analysis of skin erythema, making it possible to compare readings from different environmental light conditions.

PATIENTS AND METHODS

Three hundred and forty-eight Caucasian adult healthy subjects (age range: 18-60 years) of both sexes (14% males, 86% females), were enrolled in the study by 49 dermatologists distributed all over Italy. They were recruited among patients who required aesthetic treatments involving skin erythema, like chemical peeling and laser epilation. Once the treatment was administered, clinical evaluations and pictures were taken at the level of treated areas. Visual assessment of erythema was done on the basis of conventional clinical grades (0 = absent; 1 = slight; 2 = moderate; 3 = intense). The clinicians participating in the study were asked to put a standard colour marker (red, green and blue coloured self-adhesive ring) in the photographed skin area. The difference between r, g, b values of photographed colour markers on the skin of single patients participating in the study and the r, g, b values obtained photographing the colour marker in fixed illumination conditions was used to adjust skin colour measurements. Then erythema index (E.I) on digitized images was calculated subtracting red value to green one by averaging procedure of different pixels.

RESULTS

Erythema index. average value among the groups divided according to the conventional clinical score increased progressively from score 0-2, while it decreased from score 2 to score 3. The differences in E.I. mean values among the score groups (0 vs. 1, 1 vs. 2, 2 vs. 3) were statistically significant (P < 0.05).

CONCLUSION

We developed a method for the measurement of skin erythema using digital camera, normalized r, g, b colour co-ordinate system and computerized calculation of E.I. Clinical usefulness of our method for absent, slight and moderate erythema, was demonstrated. For intense erythema lesions we did not find a correspondence between clinical and computerized evaluation, probably due to other factors involved in skin inflammation (e.g. oedema).