Trichoscopy

From dermoscopedia

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 Editor: Anna Waskiel Burnat

 Author(s): Lidia Rudnicka     ·  Anna Waskiel Burnat     ·  Adriana Rakowska
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Description This chapter describes 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. of hair and scalpThis glossary term has not yet been described. (TrichoscopyThis glossary term has not yet been described.).
Author(s) Lidia Rudnicka · Anna Waskiel Burnat · Adriana Rakowska
Responsible author Anna Waskiel Burnat→ send e-mail
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Status update May 22, 2019
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This chapter describes dermoscopy of hair and scalp (Trichoscopy).

It has the following subchapters:

Trichoscopic structures and patterns Anna Waskiel Burnat, Lidia Rudnicka, Adriana Rakowska
Aqcuired nonscarring alopecia (Androgenetic alopecia,Alopecia areata, Trichotillomania, Telogen effluvium) Anna Waskiel Burnat, Lidia Rudnicka, Adriana Rakowska
Primary cicatricial alopecia Anna Waskiel Burnat, Lidia Rudnicka, Adriana Rakowska
Inflammatory scalp diseases Anna Waskiel Burnat, Lidia Rudnicka, Adriana Rakowska


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Normal trichoscopyThis glossary term has not yet been described. findings

Trichoscopy in healthy persons is characterized by:


1. Mean hair thickness more than 0,053 mm in the frontal area and more than 0,050 mm in the othersThis glossary term has not yet been described.This glossary term has not yet been described. (temporal and occipital)

2. Percentage of thin hairs less than 10% in the frontal and occipital area and less than 13% in the temporal areas

3. The percentage of pilosebaceous units with single hair less than 35% in the frontal area, 30% in the occipital area and 40% in the temporal areas

4. Yellow dots less than 4 in 4 fields of vision with 70-fold magnification in the frontal area and only 1 in the others

5. Perifollicular discoloration lower than 25% in the frontal area, lower than 15% in the occipital area and 20% in the temporal area

6. Pinpoint vesselsThis glossary term has not yet been described. in the frontal area (80% of patients) and thin arborizing vesselsanalytic term is branched vessels; Bright red sharply in focus large or thick diameter vessels dividing into smaller vessels; BCC in occipital and temporal areas

Trichoscopic structuresThis glossary term has not yet been described. and patternsThis glossary term has not yet been described.

Hair shafts

Fractured hairsThis glossary term has not yet been described.

Trichoptilosis Trichoschisis or trichoclasis Broken hairs Golf tee hairs
Longitudinal splitting of the distal end of hair shaftThis glossary term has not yet been described. A clean transverse fracture across the hair shaft Irregular transverse fracture across the hair shaft A hair with a concave distal end
Unspecific manifestation of a defect in hair shaft structure Trichothiodystrophy, secondary to conditions that weaken the hair shaft TrichotillomaniaThis glossary term has not yet been described., traction alopecia, alopecia areataThis glossary term has not yet been described., tinea capitisThis glossary term has not yet been described. Specific for Netherton syndrome

Narrowings

Monilethrix Monilethrix-like congenital Hypotrichosis Monilethrix-like hairs (Pohl-PinkusThis glossary term has not yet been described. constriction) Pseudomonilethrix Exclamation mark hairs Tapered hairs
Hair with regularly distributed nodes and narrowings

The nodes correspond to normal hairThis glossary term has not yet been described. shaft thickness; the internodes are the narrowings

As in monilethrix, but the spaces between narrowings are extremely short Hair with irregularly distributed narrowings (Pohl-Pinkus constrictions) Differs from monilethrix—nodes appear thicker than the normal hair shaft and internodes have the thickness of the normal hair Hairs with a thin, usually hypopigmented proximal end and thicker, pigmented distal end Long exclamation mark hairs, the distal end is outside the field of view of a dermoscope
Specific for monilethrix Specific for monilethrix-like congenital hypotrichosis Alopecia areataThis glossary term has not yet been described., chemotherapyinduced alopecia, bleeding, malnutrition Artificial: monilethrix-like effect from hair styling gel or immersionThis glossary term has not yet been described. fluid Controversial Alopecia areata, chemotherapyinduced alopecia, intoxication, trichotillomaniaThis glossary term has not yet been described. Alopecia areata, cicatricial alopeciaThis glossary term has not yet been described., trichotillomania, bleeding, malnutrition, chronic intoxication

Node-like appearance

Trichonodosis (hair knotting) Trichorrhexis nodosa Trichorrhexis invaginata (bamboo hairs) Hair casts (peripilar keratin casts)
A single or double knot in the hair shaft A hair shaft with a restricted area where the shaft splits longitudinally into numerous small fibers

The outer fibers bulge out, causing a segmental increase in hair diameter

The hair shaft telescopes into itself

The proximal part of the abnormality is concave and the distal end is convex (bulging), producing an impression of nodular swelling along the hair shaft

Firm, white, tubular masses that encircle the hair shafts
No clinical significance Multiple acquired and inherited diseases, commonly due to mechanical or chemical traumaThis glossary term has not yet been described. Specific for Netherton syndrome A nonspecific finding, commonly associated with scaling or epidermal detachment Traction alopecia

Curls and twists

Pigtail hairs Coiled hairs Comma hairs Corkscrew hairs Zigzag hairs Pili torti Wooly hairs
Short, regularly coiled hairs with tapered ends Irregularly coiled hairs with a jagged end

When not fully coiled, they may have a hook-like appearance

Short, comma-like (C-shaped) hairs, homogeneous in thickness and pigmentation Hairs with multiple twists and coils, forming corkscrew-like structures Hairs, bent at sharp angles, form zigzag structures Hairs that are flattened and twisted on their own axis at irregular intervals, usually through an angle of 180° Hair shafts with waves at very short intervals, giving a crawling snake appearance
Alopecia areata Trichotillomania Tinea capitisThis glossary term has not yet been described. Tinea capitis Tinea capitis, alopecia areata Associated with multiple inherited and acquired hair diseases Inherited syndromes

Bands

Continuous Medulla Interrupted Medulla Pili annulati Interrupted (Morse Code-like) hairs
Longitudinal white band along the midpart of the hair shaft that covers less than 50% of the hair shaft thickness Interrupted longitudinal white band along the midpart of the hair shaft

The band covers less than 50% of the hair shaft thickness

Hair shafts with transverse light, blurry, whitish bands covering (nearly) the width of a hair Hairs with multiple thin white bands across the hair shaft
Normal Normal Hair shafts with transverse light, blurry, whitish bands covering (nearly) the width of a hair Tinea capitis

Short hairs

Upright regrowing Vellus hairs Dark lines Tulip hairs Block hairs i-Hairs Broom hairs Broom fibers Flame hairs
New, healthy, regrowing hairs that have a tapered end and a straight-up position Short, thin, hypopigmentedThis glossary term has not yet been described., delicate, nonmedullated hairs, usually somewhat wavy in shape Thin, short, intensely pigmented hairs, appearing tapered at both sides Short hairs with a tulip leaf-like hyperpigmentation at the distal end Very short hairs with a transverse horizontal distal end i-Hairs are block hairs with an accented dark distal end Few or more linear, short hairs emerging from one follicular opening Few or more linear, short, dark fibers (significantly thinner than terminal hairs) emerging from one follicular opening Hair residues, semitransparent, wavy, and cone-shaped, resembling a fire flame
Normal; If abundant, may reflect a regrowth phase of telogen effluviumThis glossary term has not yet been described. Normal; If abundant, may reflect androgenetic alopeciaThis glossary term has not yet been described. Noncicatricial alopecia Trichotillomania Noncicatricial alopecia associated with shaft hair fragility Noncicatricial alopecia associated with high shaft hair fragility (eg, tinea capitis) Observed in diverse entities, both cicatricial and noncicatricial Observed in diverse entities, both cicatricial and noncicatricial Trichotillomania

Hair follicle openingsThis glossary term has not yet been described.

"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)." correspond to hair follicle openings observed in trichoscopic examination [1].



Black 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).

Black dots, also known as “cadaverized hairs”, represent pigmented hairs broken or destroyed at scalp level [1]. They are commonly observed in alopecia areata [3], dissecting cellulitis [4, 5], trichotillomania [6] and tinea capitis [4]. Black dots may be also detected in chemotherapy-induced alopecia [4], lichen planopilarisThis glossary term has not yet been described. [7], 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. [7], traction

"Dots" correspond to hair follicle openings observed in trichoscopic examination [1].



Yellow dots

Yellow dots correspond to follicular infundibula filled with sebum and/or keratotic material [10]. They present as yellow, or whitish, round or polycyclic dots, varied in size and uniformed in colorColor (American English) or colour (Commonwealth English) is the characteristic of human visual perception described through color categories, with names such as red, yellow, purple, or blue., devoid of hairs or containing miniaturized, cadaverized or dystrophic hairs [10-12].
In alopecia areata, yellow dots are characterized by an abundant amount and regular distribution and predominate in long-lasting, inactive diseaseThis glossary term has not yet been described. [3, 13].
The predominance of yellow dots (they are predominantly sebaceous) in the frontal area compared to the occipital area is characteristic for androgenetic alopecia [14]. They correspond to empty follicular openings of follicles in kenogen phase.
In discoid lupus erythematosus, large, dark yellow dots that correspond to wide infundibula filled with keratotic material are observed [1, 5].
Yellow dots, appearing as large "3D" soap bubbles imposed over dark dystrophic hairs are specific for dissecting cellulitis [1, 5].
Sparse yellow dots may also be detected in chronic telogen effluvium [8, 9], traumatic alopecia [8] traction alopecia [7], congenital hypotrichoses and kerion celsi [15].



Red dots

Red dots correspond to widened infundibula plugged by keratin and surrounded by dilated vessels and extravasated erythrocytes [16]. They are characteristic trichoscopic finding for active discoid lupus erythematosus and believed to be a positive prognostic factor [5].



White dots

There are two types of white dots.
The classic, big, irregular white dots correspond to areas of perifollicular fibrosis and are observed most commonly in lichen planopilaris [1].
The small, regular pinpoint white dots represent hair follicle openings and eccrine sweat gland openings and are observed in sun exposed areas and in dark skin phototypes regardless of hair loss [1].



Perifollicular and interfollicular skin surface

In trichoscopy, following perifollicular and interfollicular skin surface abnormalities may be observed: scaling, discoloration, discharge and surface structure.

Scaling

Epidermal scaling can be divided into perifollicular and diffuse [13].

Mild diffuse scaling may be observed in healthy persons with dry skinThis glossary term has not yet been described.. White moderate to severe diffuse scaling is detected in psoriasisThis glossary term has not yet been described., discoid lupus erythematosus and contact dermatitisalso known as eczema is a group of diseases that results in inflammation of the skin.. Yellowish moderate to severe diffuse scaling is presented in seborrheic dermatitisThis glossary term has not yet been described., discoid lupus erythematosus and ichthyosis [13].

White perifillicular, tubular scaling is characteristic for lichen planopilaris. In folliculitis decalvans, yellowish, tubular with collar formation is observed [13]. It needs to be emphasized, that diffuse “scaling” with formation of white perifollicular clusters may be present in monoclonal gammopathy [13].



Discoloration

Brown areas in trichoscopy may occur in three different patterns.
Honeycomb pattern comprises a homogenous, mosaic or contiguous brown rings. It may be observed in chronically sun-exposed areas of thinning or complete hair loss and the scalp of dark-skinned patients [17]. Perifollicular brown coloration results from perifollicular lymphocytic infiltration [14] and is commonly detected in androgenetic alopecia, telogen effluvium. It may be presented in up to 10% of hair follicle openings in healthy persons [14, 18]. Scattered brown discoloration is typical feature of discoid lupus erythematosus [5].

Pink, “strawberry ice cream” areas are characteristic trichoscopic findings of cicatricial alopecia and correspond to early fibrosis [5].

Red areas may be observed in case of inflammationThis glossary term has not yet been described., extravasation, epidermal detachment and vascular abnormalities [13].

White areas are common feature of cicatricial alopecia and correspond to late fibrosing process [5]. They may be also observed in epidermal detachment and edema [13].

Yellow areas are detected in dissecting cellulitis, follicular pustules, dissecting cellulitis and bacterial infections [13].



Discharge

Yellow or yellow-red discharge is detected in folliculitis decalvans, bacterial infections, dissecting cellulitis or tinea capitis [13].



Surface structure

Starburst patternThis pattern consists of peripheral globules, pseudopods or streaks (or a combination of them), located around the entire perimeter of the lesion hyperplasia results from fibrosis and is characteristic trichoscopic findings of folliculitis decalvans [5].


Blood vesselsare the part of the circulatory system, and microcirculation, that transports blood throughout the human bodyThis glossary term has not yet been described. (scalp)

Comma vesselslinear curved short vessels dermal nevi Dotted vesselstiny pinpoint vessels Hairpin vessels Elongated hairpin vessels Straight linear vesselsLinear mildly curved vessels considered irregular when different sizes shapes and curves with a haphazard or random distribution are presented and considered regular when short and fine (thin) linear vessels prevail various diagnoses Thin arborizing vessels Thick arborizing vessels Capillary blood extravasations Concentric perifollicular vessels Milky red globulesThis glossary term has not yet been described. Linear helical vesselscorkscrew twisted looped vessels with bends twisted along a central axis melanoma metastasis Lace-like vessels Glomerular vessels Serpentine vesselslinear irregular vessels with multiple bends. Seen with flat BCC and melanoma Thick root-like vessels Vessel nets
C-shaped or slightly curved vesselscomma vessels - linear curved short vessels - dermal nevi monomorphous vessels: one type of vessel dominates Tiny, red dots densely aligned next to each other Small, linear looped vesselsmetaphoric term: hairpin vessels <br />

two parallel linear vessels forming a half looped or hairpin like structure <br />

seen in seborrheic keratosis viral warts
Elongated, linear looped vessels Straight linear vessels Thinner than the average terminal hair arborizing vessels Thicker than the average terminal hair arborizing vessels Round or oval, sharply demarcated, intensely red areas VesselsThis glossary term has not yet been described. (loops or linear) arranged concentrically around a follicular unit Globules or larger areas of a fuzzy or unfocused milky red color Linear vesselsLinear mildly curved vessels considered irregular when different sizes shapes and curves with a haphazard or random distribution are presented and considered regular when short and fine (thin) linear vessels prevail various diagnoses twisted along a central axis CombinationThis glossary term has not yet been described. of serpentine and looped vessels Coiled or twisted vessels Bending, scarcely branching vessels Thick, irregularly banded, linear vessels Interfollicular networkThis glossary term has not yet been described. of blood vesselsare the part of the circulatory system, and microcirculation, that transports blood throughout the human bodyThis glossary term has not yet been described.
Inflammatory scalp diseases (seborrheic dermatitis, psoriasis), healthy persons Healthy persons in the frontal area, eczema Healthy persons in the frontal area Cicatricial alopeciaThis glossary term has not yet been described. (lichen planopilaris, folliculitis decalvans), T-cell lymphomaThis glossary term has not yet been described. Pemphigus vulgaris Healthy persons (the occipital and temporal area), seborrheic dermatitis 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., basal cell carcinomais the most common skin cancer, and one of the most common cancers in the United States.[1] While BCC has a very low metastatic risk, this tumor can cause significant disfigurement by invading surrounding tissues Active psoriasis Cicatricial alopecia (lichen planopilaris, folliculitis decalvans) T-cell lymphoma, psoriasis PsoriasisThis glossary term has not yet been described., pemphigus, T-cell lymphoma Psoriasis Psoriasis Discoid lupus erythematosus Discoid lupus erythematosus, congenital capillary malformations Healthy persons, after topical corticosteroids


Perifollicular and interfollicular skin surface

Blood vessels (scalp)

Normal trichoscopic findings

Aqcuired nonscarring alopeciaThis glossary term has not yet been described.

Primary cicatricial alopecia

Inflammatory scalp diseases