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 Table of Contents  
Year : 2014  |  Volume : 1  |  Issue : 1  |  Page : 3-5

Importance of skin color in therapeutic and diagnostic applications

Department of Dermatology, Venereology, and Leprosy, Vinayaka Missions Medical College, Karaikal, Puducherry, India

Date of Web Publication13-Jun-2014

Correspondence Address:
Dr. Srivenkateswaran Kothandapany
178, Church Street, Karaikal - 609 602, Puducherry
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/2349-4220.134442

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How to cite this article:
Kothandapany S. Importance of skin color in therapeutic and diagnostic applications. Int J Adv Med Health Res 2014;1:3-5

How to cite this URL:
Kothandapany S. Importance of skin color in therapeutic and diagnostic applications. Int J Adv Med Health Res [serial online] 2014 [cited 2022 Aug 11];1:3-5. Available from: https://www.ijamhrjournal.org/text.asp?2014/1/1/3/134442

  Introduction Top

Human skin color tones fall within a small gamut of the complete spectrum of color.It is difficult to describe skin tones in verbal expression. However, now with the help of a conceptual entity - color space - color can be expressed in numerical figures. These values are useful in comparing tones for medical research, industrial cosmetic use, and the like. Many color space variations - Commission Internationale de l'éclairageL*a*b* (CIE L*a*b*), sRGB (Standard Red Green Blue), Adobe RGB (Adobe Red Green Blue), HSV (Hue Saturation Value), and CMYK (Cyan Magenta Yellow Black), have been described and preferred according to the need [Table 1]. CIE L*a*b* space is a device-independent color space that consists of three axes L*, a*, and b*. All colors can be accommodated within the coordinate values in L*, a*, and b* color space. Difference in color values can be expressed in terms of CIE delta E*ab. When the delta E*ab values are more than 2.5, it produces a significant color difference noticeable to the naked human eye.
Table 1: List of various color spaces and their main applications

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  Color Spaces Top

There are variations of skin color within the sun-exposed and sun-covered parts of our body. Even among twins there are color differences. Skin color of the gluteal region represents constitutive color, whereas, the color of the cheek represents a facultative color. Epidermal melanin and melanosome size influences the L* (lightness) values. Constitutional dark skin has a lower L* value. [1] Erythema and tanning can be measured objectively using colorimetry. The a* values indicate erythema, while the b*(yellow-blue) values indicate tanning, and the transition from erythema to tanning can be measured objectively. [2] Exposed areas like the cheek have increased a* values, which indicate a red-green axis because of increased vascularization. [3] The b* value also increases in direct proportion with the carotenoid level of the skin. [4] There is an 8.2% increase in skin reflectance values for every ten degrees of increase in latitude in the Northern hemisphere, in males. Only a 3.3% increase has been noted for the latitudes in the Southern hemisphere, indicating that the skin color is darker in the Southern hemisphere for the corresponding latitude. [5]

The color of newborns can provide information about their health status. Similarly the color space values of the skin of aged persons can provide information about their health, nutritional status, and the like. The color of ulcers varies over a period of time indicating the healing process. There was a 5 nmol/L increase in 25 hydroxy vitamin D3 levels for every 10 degrees of lower colorimetric skin values in the forearm (exposed skin), indicating that the forearm color can be a reliable indicator for the vitamin D3 status. [6]

  In Skin Diseases Top

A minimal erythema dose (MED) was defined as an increase in the a* value by 2.5 units. A significant risk for melanoma was found with increasing a* values in patients. [7] An objective assessment of erythema in psoriasis was useful in the determination of the Psoriasis Area and Severity Index (PASI) scores. [8] There was a significant relationship between the L* values and MED values of the skin, but this was not significant for the a* and b* values.

The MED value for Narrowband Ultraviolet B (NBUVB) radiation has become a basic criterion for the phototherapy protocol. Hence, the skin type and L* value are useful for predicting the response to NBUVB therapy. [9] The L* value can replace MED estimation for starting Narrowband UV therapy. The starting doses based on L* values are given - 300 mJ/cm 2 when the L* value is more than 66, 400 mJ/cm 2 when the L* value is between 62 and 66, and 500 mJ/cm 2 when the L* value is less than 62. [10] The L*a*b* values can be used to measure the difference in pigmentation in vitiligo. In patients with Acanthosis nigricans, the L* values are found to correlate with hyperpigmentation. [11]

  Cosmetology Top

The color of scars can be evaluated with the help of L*a*b* coordinates and can be reliable for assessing the color contrast with normal skin. [12] In grafting, L* and a* values of skin grafts can be compared with the adjacent recipient skin, which will be useful in the final cosmetic outcome. [13] Similar matching can be done between the skin flap of the donor and recipient sites. The skin of the upper extremities and the trapezius flaps of Caucacians, South Asians, and Southeast Asians match closely for grafts required in the cheek and other facial regions. [14] Color data obtained from a spectrophotometer is used for color mixing and preparation of a facial prosthesis. [15] The L*a*b* values are used to compare the silica prosthesis with the original color of the subject. The highest correlation is found in the b* values for a prosthesis with a thickness of 1-4 mm. Good correlation was found with the L* values when the thickness was 6-10 mm. [16] The whitening effect on the skin color (Lightness Value) of the pigmented lesions can be compared after the use of intense pulsed light (IPL), in patients using this technique. [17]

  Dermatopharmacology Top

Digital analysis of photographs was found to be useful to assess the prick test reaction to histamine and dermatophagoides antigens, and tests were done at 0-, 3-, 5-, 10-, 15-, and 29-minute intervals. [18] The efficacy of drugs in controlling the flare reaction of histamines was assessed in a study and color space values were found to be useful. [19] Difference in the skin color a* values were assessed for postural changes in the limbs, during a vasoconstrictor assay using topical corticosteroids. [20]

  Effect of Toxins Top

The skin color of End Stage Renal Disease (ESRD) Taiwanese patients on dialysis were compared with the controls, on the sun-exposed and sun-covered regions of the body. It was observed that the L* values were lower in the sun-covered areas in both hemodialysis and peritoneal dialysis patients. [21] In another study on the maintenance of hemodialysis patients, the skin was found to have significant hyperpigmentation when compared with the matched controls. [22] Patients who stopped smoking were assessed for their skin color changes. Lightness of skin improved and the redness decreased 12 weeks after cessation of smoking. [23] The Melanin Index and Erythema Index reduced significantly after four weeks of smoking cessation. [24]

  References Top

1.Alaluf S, Atkins D, Barrett K, Blount M, Carter N, Heath A. The impact of epidermal melanin on objective measurements of human skin colour. Pigment Cell Res 2002;15:119-26.  Back to cited text no. 1
2.Seitz JC, Whitmore CG. Measurement of erythema and tanning responses in human skin using a tri-stimulus colorimeter. Dermatologica 1988;177:70-5.  Back to cited text no. 2
3.Andreassi L, Casini L, Simoni S, Bartalini P, Fimiani M. Measurement of cutaneous colour and assessment of skin type. Photodermatol Photoimmunol Photomed 1990;7:20-4.  Back to cited text no. 3
4.Alaluf S, Heinrich U, Stahl W, Tronnier H, Wiseman S. Dietary carotenoids contribute to normal human skin color and UV photosensitivity. J Nutr 2002;132:399-403.  Back to cited text no. 4
5.Relethford JH. Hemispheric difference in human skin color. Am J Phys Anthropol 1997;104:449-57.  Back to cited text no. 5
6.Rockell JE, Skeaff CM, Williams SM, Green TJ. Association between quantitative measures of skin color and plasma 25-hydroxyvitamin D. Osteoporos Int 2008;19:1639-42.  Back to cited text no. 6
7.Chiarugi A, Ceroti M, Palli D, Cevenini G, Guarrera M, Carli P. Sensitivity to ultraviolet B is a risk factor for cutaneous melanoma in a Mediterranean population: Results from an Italian case-control study. Clin Exp Dermatol 2009;34:8-15.  Back to cited text no. 7
8.Ahmad Fadzil MH, Ihtatho D, Affandi AM, Hussein SH. Objective assessment of psoriasis erythema for PASI scoring. Conf Proc IEEE Eng Med Biol Soc 2008;2008:4070-3.  Back to cited text no. 8
9.Youn JI, Park JY, Jo SJ, Rim JH, Choe YB. Assessment of the usefulness of skin phototype and skin color as the parameter of cutaneous narrow band UVB sensitivity in psoriasis patients. Photodermatol Photoimmunol Photomed 2003;19:261-4.  Back to cited text no. 9
10.Kwon IH, Kwon HH, Na SJ, Youn JI. Could colorimetric method replace the individual minimal erythemal dose (MED) measurements in determining the initial dose of narrow-band UVB treatment for psoriasis patients with skin phototype III-V? J Eur Acad Dermatol Venereol 2013;27:494-8.  Back to cited text no. 10
11.Pattamadilok B, Devpura S, Syed ZU, Agbai ON, Vemulapalli P, Henderson M, et al. Quantitative skin color measurements in acanthosis nigricans patients: Colorimetry and diffuse reflectance spectroscopy. Photodermatol Photoimmunol Photomed 2012;28:213-5.  Back to cited text no. 11
12.Cheon YW, Lee WJ, Rah DK. Objective and quantitative evaluation of scar color using the L*a*b* color coordinates. J Craniofac Surg 2010;21:679-84.  Back to cited text no. 12
13.Kwon SG, Lee DW, Rah DK, Lee WJ. Skin-fat composite grafts on full-thickness facial skin defects. Ann Plast Surg 2013;71:176-80.  Back to cited text no. 13
14.Ngo K, Goldstein D, Neligan P, Gilbert R. Colorimetric evaluation of facial skin and free flap donor sites in various ethnic populations. J Otolaryngol 2006;35:249-54.  Back to cited text no. 14
15.Coward TJ, Seelaus R, Li SY. Computerized color formulation for African-Canadian people requiring facial prostheses: A pilot study. J Prosthodont 2008;17:327-35.  Back to cited text no. 15
16.Over LM, Andres CJ, Moore BK, Goodacre CJ, Muñoz CA. Using a colorimeter to develop an intrinsic silicone shade guide for facial prostheses. J Prosthodont 1998;7:237-49.  Back to cited text no. 16
17.Kawada A, Kawara S, Oiso N, Endo H, Yoshinaga E, Konishi N, et al. An evaluation of whitening effect of an intense pulsed light source using computer analysis of the video-captured digital image. Arch Dermatol Res 2008;300(Suppl 1):S39-41.  Back to cited text no. 17
18.dos Santos RV, Titus RG, Lima HC. Objective evaluation of skin prick test reactions using digital photography. Skin Res Technol 2007;13:148-53.  Back to cited text no. 18
19.Nischik M, Forster C. Analysis of skin erythema using true-color images. IEEE Trans Med Imaging 1997;16:711-6.  Back to cited text no. 19
20.Henry F, Fumal I, Piérard GE. Postural skin colour changes during the corticosteroid blanching assay. Skin Pharmacol Appl Skin Physiol 1999;12:199-210.  Back to cited text no. 20
21.Lai CF, Kao TW, Tsai TF, Chen HY, Huang KC, Wu MS, et al. Quantitative comparison of skin colors in patients with ESRD undergoing different dialysis modalities. Am J Kidney Dis 2006;48:292-300.  Back to cited text no. 21
22.Deleixhe-Mauhin F, Krezinski JM, Rorive G, Piérard GE. Quantification of skin color in patients undergoing maintenance hemodialysis. J Am Acad Dermatol 1992;27:950-3.  Back to cited text no. 22
23.Ishiwata T, Seyama K, Hirao T, Shimada K, Morio Y, Miura K, et al. Improvement in skin color achieved by smoking cessation. Int J Cosmet Sci 2013;35:191-5.  Back to cited text no. 23
24.Cho YH, Jeong DW, Seo SH, Lee SY, Choi EJ, Kim YJ, et al. Changes in skin color after smoking cessation. Korean J Fam Med 2012;33:105-9.  Back to cited text no. 24


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