Clinical and trichoscopic correlation of primary neutrophilic scarring alopecia: folliculitis decalvans and dissecting cellulitis

Trichoscopy is the term coined for the dermoscopic imaging of scalp and hair. This diagnostic technique, simple and noninvasive, can be used as a handy bedside tool for the diagnosis and follow-up of hair and scalp disorders. It allows the recognition of morphologic structures not visible by the naked eye and provides the clinician with a range of dermoscopic findings necessary for differential diagnosis. Trichoscopy observation can be broadly grouped as interfollicular patterns and follicular patterns. Recently, a third mixed class, called the follicular plus interfollicular pattern, has been introduced. Some of these features are specific to a certain scalp disease, while others can be found in many hair disorders. Although studies suggest that the use of trichoscopy can improve clinical accuracy, further investigation is needed. This review provides update information on the trichoscopic features of the most common scalp disorders, striving to show a histopathological and clinical correlation.