This chapter describes tricoscopy structuresThis glossary term has not yet been described. and patternsThis glossary term has not yet been described. as seen by 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.
Normal trichoscopyThis glossary term has not yet been described. findings
TrichoscopyThis glossary term has not yet been described. 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
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 scalpThis glossary term has not yet been described. 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.
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
