Polarized Versus Nonpolarized Dermoscopy for Hair and Scalp Evaluation.

Sir,

We read with interest the study by Nikam and Mehta,[1] comparing polarized and nonpolarized dermoscopy for hair and scalp. The study has been well designed, and the results are quite interesting. We would like to just mention the possibility of the results being affected by the quality of the instruments themselves. The Dermlite II and the Heine (it was not mentioned which specific Dermlite II or Heine dermoscopes were used, but I assume based on the description that it was the Dermlite II pro), have different lighting systems and lens quality. Moreover, the images shown in the article would also be expected to have a difference in quality because as the authors mention for the Heine dermoscope a single-lens reflex was used unlike the Dermlite II. We feel that the study would probably have been more effective if a hybrid dermoscope like the Dermlite II hybrid M or Dermlite DL3 was used to evaluate the lesions where at least parameters like the lens quality will be the same.

We have been using two different dermsocopes from Dermlite for the last few years – A pro HR II (having an option of 16/32 cross polarized lights) and a Dermlite multispectral (having four color polarized light – 8 light-emitting diodes [LED] each of white, blue, red, and yellow). There is an obvious difference in the quality of hair imaging even between the two devices when the white cross polarized light is used, basically because of the lesser number of dedicated white light LEDs. Hence, it would seem that quality and strength of LEDs, quality of the lens and also to some extent quality and capacity of the image capture device would affect the quality of dermoscopy.

Ideally, we agree that when both modes are available, polarized and nonpolarized dermoscopy for the hair, as in the skin, can be complementary to each other.[2]

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.