Dermoscopy or epiluminescence microscopy is a simple, noninvasive method to examine the subsurface features of the skin invisible to the naked eye. It serves as a telescope through which the intricate details of a lesion in the epidermis and superficial dermis can be appreciated at a greater magnitude. Normally, light is reflected and scattered by the stratum corneum thus making the structures in the epidermis and superficial dermis invisible to the eye. This pitfall is superseded by a dermoscope, which decreases scattering of light and increases transillumination either through polarized light or through linkage fluids; allowing visualization of subsurface structures.
The orange hue at dawn signals the advent of the rising sun. Similarly, colors on dermoscopy underline the depth and nature of the structure being observed.
The naked eye cannot appreciate the vascular morphology of lesions such as a hemangioma or pyogenic granuloma. It is through the dermoscope that we can identify various vascular structures such as lacunae or red homogeneous areas and understand what the color red stands for. In dermoscopic language, it indicates either vasculature or traumatic extravasation of blood. Dermoscope provides a telescopic view into the vascular world of subsurface. It enlightens us not only about the location of the blood vessels but also their course in the dermis. Vessels seen as dots or loops on dermoscopy are placed in the papillary dermis whereas linear vessels correspond to the subpapillary plexus. Also, linearity of the vessels on dermoscopy suggests that they run parallel to the epidermis whereas dotted vessels signify a perpendicular orientation to the epidermis.
A granulomatous lesion like lupus vulgaris or sarcoidosis or a xanthogranuloma presents clinically in varied forms. Dermoscopy in such cases noninvasively demonstrates orangish yellow structures, which indicate granulomas, and guides the clinician towards correct differentials.
A nevus to the naked eye looks like an innocent macule or nodule. Dermoscopy provides a window into its subsurface and designates the location of melanocytes and the need for biopsy. A pigmented or a globular network suggests junctional activity of the melanocytes whereas a cobblestone pattern indicates a dermal nest of melanocytes. A clinical view of a pigmented lesion in most cases is inadequate to classify it as benign or malignant. Magnification on dermoscopy provides vital clues; eccrine atypical network or irregular streaks or a bizarre dermoscopic image leaning toward malignancy. Dermoscopy also helps to allocate the location of chromophores in the skin. Melanin in the upper and lower epidermis is seen through a dermoscope as black and brown respectively, whereas melanin in the papillary and reticular dermis is seen as gray and bluish gray respectively.
The naked eye is incapable of visualizing the shaft or the root of the hair. Dermoscopy offers a visual window into the appendageal world. If the hair root is destroyed, it will be seen as a fibrotic white dot on trichoscopy indicating cicatrization. A circumscribed bald patch on the scalp clinically ignites the possibilities of alopecia areata, trichotillomania, etc. But it is the demonstration of exclamation mark hair or Pohl-Pinkus constriction through a dermoscope that indicates disease activity in alopecia areata thereby offering a trichoscopic confirmation of the disease as well.
Dermoscopy opens up a whole new world of the subsurface. It is an essential tool in day-to-day practice as it offers a telescopic view of pigment patterns, vascular patters and appendageal structures.