![]()
1 Introduction to Dermoscopy
Introduction to Dermoscopy
Introduction
Viewing the invisible world …
Instruments
Non-polarised devices (oil immersion/contact)
Polarised devices
Hybrid devices
Which device is best?
Device comparisons I
The Heine Delta 20 versus the DermLite II PRO HR
Chrysalis structures
Device comparisons II
Comparisons of contact versus non-contact polarisation: structures in a seborrhoeic keratosis
Comparison of the polarising mode and the non-polarising mode – the DermLite II Hybrid m
Device comparisons III
DermLite DL3 versus DermLite II PRO HR versus Heine Delta 20
Device maintenance tips
Normal skin
Skin phototype I
Skin phototype V
Photodamaged skin I
Acute photodamage
Chronic photodamage
Photodamaged skin II
Examples of photodamaged skin
Pigment depth and colour
The dermoscopic alphabet
Introduction to Dermoscopy
Introduction
The ‘art’ of dermatological diagnosis is a complex process that requires many skills.
If dermatologists were to be described in a single word, they would be ‘diagnosticians’; the ‘art’ of dermatological diagnosis requires all the skills of a physician in addition to the eyes of a hawk, for lesion diagnosis cannot be made by history alone.
Most lesions that from afar look indistinct become obviously benign or malign on closer inspection. However, there are plenty of lesions where close visual inspection is still not enough. How do we approach these lesions? Tools to aid diagnosis, such as the magnifying lens and bright light sources, can help or – failing that – a biopsy, whereby the diagnosis appears as a line on the histology report. However, simple adjustments to our clinical practice may be all that is required to improve our diagnostic ability.
To begin with, we should search for clues to diagnosis, the diagnostic detail in lesions, and not just rely upon rather crude data such as shape, size and colour for a diagnosis. Although these crude parameters are often all that is required for a diagnosis, relying solely upon them will limit your diagnostic accuracy. Imagine an art dealer investing in a painting based solely upon the shape, size, age and colour of the picture frame, without appreciating the detail in the brushstrokes of the canvas. These dermatological ‘brushstrokes’ are the morphological structures that comprise skin tumours, and unfortunately many of them are invisible to the naked eye.
Viewing the invisible world …
Two barriers need to be overcome.
First, the rough surface of the stratum corneum causes light to scatter, reducing light penetration into the skin. This scattering of light impairs the view of the morphological structures hidden within a lesion. This can be illustrated by light reflecting off the surface of this rippled pool (a), distorting the detail seen of the tiles underneath. However, if the surface is ca...
