Hair shafts

From dermoscopedia
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Description This chapter describes the dermoscopy / Trichoscopy critera of the hair shafts
Author(s) Anna Waskiel Burnat · Lidia Rudnicka
Responsible author Lidia Rudnicka→ send e-mail
Status unknown
Status update May 19, 2023
Status by Ralph P. Braun

  • A normal terminal hair are more than 55 µm wide and are uniform in thickness and color [1].
  • The trichoscopic classification of hair shaft abnormalities is proposed by Rudnicka et al. [2].

Fractured hairs

Trichoptilosis Trichoschisis or trichoclasis Broken hairs Golf tee hairs
Longitudinal splitting of the distal end of hair shaft 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 Trichotillomania, traction alopecia, alopecia areata, tinea capitis Specific for Netherton syndrome


Monilethrix Monilethrix-like congenital Hypotrichosis Monilethrix-like hairs (Pohl-Pinkus constriction) Pseudomonilethrix Exclamation mark hairs Tapered hairs
Hair with regularly distributed nodes and narrowings

The nodes correspond to normal hair 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 areata, chemotherapyinduced alopecia, bleeding, malnutrition Artificial: monilethrix-like effect from hair styling gel or immersion fluid Controversial Alopecia areata, chemotherapyinduced alopecia, intoxication, trichotillomania Alopecia areata, cicatricial alopecia, 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 trauma 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 capitis Tinea capitis Tinea capitis, alopecia areata Associated with multiple inherited and acquired hair diseases Inherited syndromes


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, hypopigmented, 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 effluvium Normal; If abundant, may reflect androgenetic alopecia 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

Adapted from Rudnicka et al. [2]

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