Dermatology: Practical and Conceptual


Commentary  |  Dermatol Pract Concept 2021;11(1):e2021141 1

Dermatology Practical & Conceptual

Utility of Blue Light in Dermoscopy for Diagnosing 
Stable Lesions in Vitiligo

Balakrishnan Nirmal1

1 Department of Dermatology, Christian Medical College, Vellore, India

Key words:  vitiligo, amelanotic vitiligo, blue light, dermoscopy

Citation: Nirmal B. Utility of blue light in dermoscopy for diagnosing stable lesions in vitiligo. Dermatol Pract Concept. 
2021;11(1):e2021141. DOI: https://doi.org/10.5826/dpc.1101a141

Accepted: September 19, 2020; Published: January 29, 2021

Copyright: ©2021 Nirmal. This is an open-access article distributed under the terms of the Creative Commons Attribution License BY-
NC-4.0, which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original author and 
source are credited.

Funding: None.

Competing interests: The author has no conflicts of interest to disclose.

Authorship: The author takes responsibility for this publication.

Corresponding author:  Balakrishnan Nirmal, MD, Department of Dermatology, Christian Medical College, Vellore, India. Email: 
nimu2swash@yahoo.co.in

It is important to identify the nature of the border of a vitiligo 

lesion to ascertain the activity of the disease. Ascertaining 

disease stability is an important prerequisite before subjecting 

the patient to surgical management. Detection of an amela-

notic lesion with a sharply demarcated border (ASDB) under 

Wood lamp is considered stable. Unstable, active vitiligo 

lesions are associated with hypomelanotic appearance with 

poorly defined borders (HPDB) [1]. However, Wood’s lamp 

requires a dark room and is difficult to use in busy outpatient 

practice.

Loss of melanin in vitiligo is seen clearly with a 470-nm 

blue light source from a multispectral dermoscope (DermLite 

DLII, multispectral; 3Gen, San Juan Capistrano, CA). Mel-

anin absorption is highest in the ultraviolet spectrum and 

decreases toward a higher wavelength. Blue light from the 

dermoscope has a wavelength closer to the absorption peak 

of melanin [2] and is useful in delineating ASDB in stable 

vitiligo better than white-light dermoscopy (Figure 1). HPDB 

seen in unstable vitiligo does not show this sharp delineation 

(Figure 2). Blue light increases the contrast between lesions 

retaining melanin and areas of melanin loss, thus is useful for 

differentiating stable from unstable vitiligo.

Figure 1. Vitiligo; stable lesion. (A) White-light and (B) blue-light der-

moscopy (×10). Blue light (470 nm) delineates amelanotic vitiligo with 

the sharply demarcated border better than white-light dermoscopy.



2 Commentary  |  Dermatol Pract Concept 2021;11(1):e2021141

References

1. Benzekri L, Gauthier Y, Hamada S, Hassam B. Clinical features and 

histological findings are potential indicators of activity in lesions 

of common vitiligo. Br J Dermatol. 2013;168(2):265-271. DOI: 

10.1111/bjd.12034. PMID:.22963656.

2. Kaliyadan F, Jayasree P, Kuruvilla J, Errichetti E, Lallas A. The 

use of blue light, multispectral dermoscopy in vitiligo: A pilot 

study [published online ahead of print, 2020;26(4):612-614. Skin 

Res Technol. 2020;10.1111/srt.12837. DOI: 10.1111/srt.12837. 

PMID: 31904163.

Figure 2. Vitiligo; unstable lesion. (A) White-light and (b) blue-light dermoscopy (×10). Blue light (470 nm) does not delineate hypomelanotic 

vitiligo with the poorly defined border.