Dermoscopy – Visualising Skin Details

Feroze Kaliyadana

a. Department of Dermatology, King Faisal University, Saudi Arabia, Email: ferozkal@hotmail.com

Most dermatological conditions are diagnosed by simple inspection of the skin lesions with the naked eye or with a hand lens. Cases with diagnostic difficulty often are resolved by a skin biopsy, which though a minor procedure, is still invasive.  Dermoscopy is one of the newer non-invasive techniques used in the diagnosis of dermatological conditions.

Dermoscopy is also known by various other names like Dermatoscopy, Epiluminescence Microscopy, Surface Microscopy, and Incident Light Microscopy.  Dermoscopy essentially was used as an in vivo noninvasive technique for the evaluation of pigmented lesions of the skin, with the aim of early detection and triage of melanoma. In the case of melanoma, it helps both by early treatment of necessary cases and by avoiding unnecessary biopsies and excisions in benign conditions.1

Figure 1. Handheld dermocsope with camera

Figure 1. Handheld dermocsope with camera

Dermoscopy is done using a device similar to an otoscope, which generates a beam of light that falls on the cutaneous surface.  A gel like fluid is placed at the interface between the skin and the dermoscope’s glass slide.  This prevents reflection from the stratum corneum, allowing clear visualization of characteristic features produced by the presence of haemoglobin and melanin in the various skin layers.

Polarized Light Dermoscopes are also available with the advantages that these do not require the use of fluid interfaces.  Many of the newer hybrid compact dermoscopes have both contact and polarized light modes.

Figure 2. Handheld dermocsopy for studying nail fold capillary patterns in collagen vascular diseases

Figure 2. Handheld dermocsopy for studying nail fold capillary patterns in collagen vascular diseases

The usual magnification provided by common hand held dermoscopes is 10x (Figure 1). Sophisticated video-dermoscopy equipments are available with much higher magnifications.  These can be used in the studying nail fold capillary patters in the context of connective tissue disorders (Figure 2).2   Some companies have developed complex dermoscopy equipment with sophisticated camera attachments and software, which can be used to map the skin of the whole body, with the data being stored in a standardized format for easy follow up  of the patient. Adapters are also available which can enable hand held dermoscopes to be attached to smart phones, thus making the imaging and data storage procedure even more easy.

Figure 3a.  Clinical photograph of a wart

Figure 3a. Clinical photograph of a wart

Other than melanocytic nevi and melanoma, specific dermoscopic patterns were highlighted in other conditions like hemangiomas, basal cell carcinoma, seborrheic keratosis, actinic keratosis, Bowen’s disease, squamous cell carcinoma etc. and even infections and infestations like scabies and warts (Figure 3a & 3b).2,3,4,5  Recently more researchers have started exploring the use of dermoscopy in

Figure 3b. Dermocsopic image of the same lesion

Figure 3b. Dermocsopic image of the above lesion

the application related to common skin disorders like psoriasis, vitiligo, infections and infestations  in the context of both diagnosis and response to treatment as well as prediction of relapse.  Another area where the use of dermoscopy is increasing is in the diagnosis of hair disorders (trichoscopy).  The changes that are observed on dermoscopy of different hair conditions are very specific.   Allopecia areata produces yellow dots, Lichen Planopilaris shows peripheral peripilar casts and androgenetic alopecia shows peripilar brown depressions.

Figure 4. Dermoscopy of alopecia areata showing yellow dots, black dots, broken hairs, short vellus hair and tapering hai

Figure 4. Dermoscopy of alopecia areata showing yellow dots, black dots, broken hairs, short vellus hair and tapering hair

Structural defects like monilethrix can also be demonstrated using this technique (Figure 4).6   It is likely that in future the hand held dermoscope will  be a standard tool in the hands of the dermatologist to improve diagnostic efficacy in all types of skin lesions..

Good hand held dermoscopes with camera attachments can cost about Rs 50,000.  Cheaper alternative have been suggested by some authors like using a simple Jeweler’s loupe with 10X magnification and an inbuilt LED light. Here a fluid interface is necessary (alcohol gel being the preferred dermoscopy fluid). While such cheaper devices cannot compare to the quality of standard dermoscope, such modifications could be valuable in teaching basic dermoscopy concepts to dermatology residents in India.4

Keywords: , ,

References
  1. Carli P, De Giorgi V, Soyer HP, Stante M, Mannone F, Giannotti B. Dermatoscopy in the diagnosis of pigmented skin lesions: a new semiology for the dermatologist. J Eur Acad Dermatol Venereol 2000; 14:353–69.
  2. Campos-do-Carmo G, Ramos-e-Silva M. Dermoscopy: basic concepts. Int J Dermatol 2008; 47:712-19.
  3. Zalaudek I, Giacomel J, Cabo H, Di Stefani A, Ferrara G, Hofmann-Wellenhof R, et al. Entodermoscopy: a new tool for diagnosing skin infections and infestations. Dermatology 2008; 216: 14–23.
  4. Kaliyadan F. Using a simple Jeweler’s loupe as a dermoscopic instrument. Indian J Dermatol Venereol Leprol 2011;77:617-20
  5. Zalaudek I, Docimo G, Argenziano G. Using dermoscopic criteria and patient-related factors for the management of pigmented melanocytic nevi. Arch Dermatol 2009; 145:816-26.
  6. Ashique K T, Kaliyadan F. Clinical photography for trichology practice: Tips and tricks. Int J Trichol 2011;3:7-13

Author Information

Feroze Kaliyadan, Department of Dermatology, King Faisal University, Saudi Arabia

Conflict of Interest

None declared

 

Leave Your Comment

*