Correlation of trichoscopy (hair and scalp dermoscopy)
Editor: Oriol Yélamos
|Description||This chapter covers the correlation of trichoscopyThis glossary term has not yet been described. (hair and scalpThis glossary term has not yet been described. dermoscopyThe examination of [skin lesions] with a 'dermatoscope'. This traditionally consists of a magnifier (typically x10), a non-polarised light source, a transparent plate and a liquid medium between the instrument and the skin, and allows inspection of skin lesions unobstructed by skin surface reflections. Modern dermatoscopes dispense with the use of liquid medium and instead use polarised light to cancel out skin surface reflections.)|
|Author(s)||Oriol Yélamos · Ralph P. Braun · Daniel Morgado · Constanza Riquelme-Mc Loughlin|
|Responsible author||Oriol Yélamos → send e-mail|
|Status update||November 17, 2019|
|Status by||Ralph P. Braun|
Trichoscopy, Hair, Scalp, Dermoscopy, Histopathology Correlation of trichoscopy (hair and scalp dermoscopy) – cite! Correlation of trichoscopy (hair and scalp dermoscopy) (message) Correlation of trichoscopy (hair and scalp dermoscopy) – participate!
TrichoscopyThis glossary term has not yet been described. is the dermoscopic study of inflammatoryThis glossary term has not yet been described., infectious and artefactual hair and scalp disorders. It can helpRefers to giving assistance or support to others for mutual benefit in the diagnosisis the identification of the nature and cause of a certain phenomenon. Diagnosis is used in many different disciplines with variations in the use of logic, analytics, and experience to determine "cause and effect". In systems engineering and computer science, it is typically used to determine the causes of symptoms, mitigations, and solutions and follow-up of these diseases (Richarz et al., 2018; Tosti, 2007) and to guide the biopsy procedure, allowing identification of even individually affected hair follicles (Miteva and Tosti, 2013). Trichoscopic structuresThis glossary term has not yet been described. or patternsThis glossary term has not yet been described. can be specific to a certain scalp disorder, although some of them can be found in diverse hair and scalp diseases (Mubki et al., 2014; Rossi et al., 2015) (table 10).
The pigment pattern is a pseudonetworkA structureless pigment area interrupted by non-pigmented adnexal openings composed of brown lines and holes. Histolopathologically, lines correspond to pigmented rete ridgesEpidermal extensions that project into the underlying dermis (Tosti, 2015).
Yellow dotsDots are small, round structures of less than 0.1 mm in diameter that have a red color when corresponding to blood vessels; however, when due to melanin, their color ranges from black, brown, to blue-gray depending on the depth and concentration of the melanin in the skin (Tyndall effect).
Yellow dots are round yellowish to pinkish structures. Histologically, they correspond to a distended follicular infundibulum plugged with keratin and sebum (Tosti, 2007). Yellow dots are characteristic of alopecia areataThis glossary term has not yet been described. (AA), although can be seen in androgenetic alopeciaThis glossary term has not yet been described. and other scalp disorders (Rossi et al., 2015; Waśkiel et al., 2018).
Black dots (“cadaverized hairs”) are round dark structures inside the follicular ostia. Histopathologically, they reveal stubs of hairs that are fractured before their emergence from the scalp. Black dots are seen in AA and are a sign of diseaseThis glossary term has not yet been described. activity (Jain et al., 2013; Miteva and Tosti, 2012).
Pinpoint white dots
Pinpoint white dots are small round whitish structures. Histologically, they correspond to follicular and sweat gland openings, and are seen in normal scalpThis glossary term has not yet been described. and in all types of alopecia (Lacarrubba et al., 2015).
White patches are large and irregular pale structures. Histologically, they represent destroyed follicles replaced by fibrous tracts and focal absence of melanin (Kossard and Zagarella, 1993). White dots are seen in cicatricial alopeciaThis glossary term has not yet been described..
Blue-gray dots are round grayish structures. They can present as a target pattern or as a speckled pattern. Blue-gray correspond to the presence melanophages in dermis. The target pattern is due to the presence of melanin around the hair follicle, and is observed in lichen planus pilaris (LPP). The speckled pattern is secondary to the presence of melanin in interfollicular areas and is seen in discoid lupus erythematosusis a chronic skin condition of sores with inflammation and scarring favouring the face, ears, and scalp and at times on other body areas. These lesions develop as a red, inflamed patch with a scaling and crusty appearance. The centre areas may appear lighter in colour with a rim darker than the normal skin. (Ankad et al., 2013; Rossi et al., 2015).
Absence of Follicular Opening
No hair follicles are seen with dermocopy. It reveals dermal fibrosis and is characteristic of scarring alopecia (Tosti, 2015).
Peripilar hair casts are concentrically arranged scales surrounding the hair shaftThis glossary term has not yet been described.. Histologically, they correspond to perifollicular inflammationThis glossary term has not yet been described.. They are frequently seen in LPP, although they can be present in other scarring alopecias and in keratinization disorders (Mubki et al., 2014; Tosti, 2015).
The Peripilar sign is a brown halo surrounding the follicular ostium. Histopathologically, it reveals perifollicular inflammation. The Peripilar sign is often seen in androgenetic alopecia (Mubki et al., 2014).
Follicular Keratotic Plugging
Follicular keratotic plugs are yellow-brownish round structures, larger than dots (Mubki et al., 2014). Histologically, they reveal hyperkeratosis and keratin material occluding dilated infundibular openings (Rossi et al., 2015).