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Clinical pearl: Tangential lighting is a simple and fast technique for evaluating canities
*Corresponding author: Muhammed Mukhtar, Katihar Medical College Road, Katihar - 854105, Bihar, India. drmmukhtar20@gmail.com
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Received: ,
Accepted: ,
How to cite this article: Mukhtar M. Clinical pearl: Tangential lighting is a simple and fast technique for evaluating canities. CosmoDerma 2022;2:112.
PROBLEM
The assessment of gray hair (canities, white hair) is difficult in the room light because the gray hair is not fully apparent. Wood’s light is an excellent choice for this.[1] However, it is not an ideal alternative in a busy clinic because the door, window, and room light are all closed and require eye protection and help from an assistant. Furthermore, tangential light has been used to visualize leukotrichia (white hair) over vitiliginous lesions.[2]
SOLUTION
To address the aforementioned concerns and their negative consequences, we recommend using general torch, pencil torch, or even mobile light (non-LED sources) of visible wavelength to examine the body, beard, and scalp hair without making the room dark. On the surface of hair or hairy skin, the light is projected at an acute angle almost near to zero degree from at least a distance of 4–6 inches or more depending on the power of light source. However, the angle and distance can be easily adjusted during examination. Following this, the gray hair becomes more noticeable in comparison to the room light [Figure 1a-f]. The reason for this is because the shadow of the hair has expanded, making it plainly apparent to the naked eye. Thus, in a busy clinic, this simple and quick procedure saves time and requires no help. It is not, however, a proper qualitative and quantitative hair analysis for graying of hair.
- (a-f) Tangential light enables better visualization of white hairs on the beard, scalp, and hands in the room light.
Declaration of patient consent
Patient’s consent not required as patient’s identity is not disclosed or compromised.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
References
- Looking for a grey needle in a “hair” stack! Using a Wood's lamp for evaluating canities. Indian J Dermatol Venereol Leprol 2022
- [CrossRef] [PubMed] [Google Scholar]
- Side lighting to enhance the visualization of leukotrichia in vitiligo. J Am Acad Dermatol. 2022;87:e59.
- [CrossRef] [PubMed] [Google Scholar]
