Dermoscopy Overview and Extradiagnostic Applications

Cutaneous diagnosis is often, but not always, visually based. Dermatologists tend to encounter situations where the possibility of multiple differentials complicates the diagnosis and mandates investigations for confirmation. Methods commonly employed for cutaneous diagnosis may be invasive (skin and scalp biopsy), semi-invasive (slit skin smears, trichogram, etc.) or non-invasive (e.g., KOH smear, nail clipping, hair count for hair loss). Dermoscopy, also known as epiluminescence microscopy, or skin surface microscopy, is a non-invasive, technique, which has traditionally found use in the evaluation and differentiation of suspicious melanocytic lesions from dysplastic lesions and melanomas, as well as keratinocyte skin cancers such as basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). Over the last several years, the use of dermoscopy has been increasing in the context of general dermatological disorders including inflammatory dermatosis, pigmentary dermatosis, infectious dermatosis, and disorders of the hair, scalp, and nails. Some terms are used to describe specific indications: pigmentaroscopy for pigmented lesions, trichoscopy of the scalp and hair, onychoscopy of the nails, inflammoscopy for inflammatory dermatosis and lesions, as well as entomodermoscopy of skin infestations and infections . The role of dermoscopy in diagnosing disorders of general dermatology has undergone elaborate discussion . In this chapter, we shall review the plethora of extra-diagnostic indications of this technique and highlight technical aspects worth considering.