An approach to hair shaft disorders in Dermatology

A complete approach to congenital and acquired hair shaft disorders

1. An approach to hair
shaft disorders in a
child
Dr Lakshmiprasad L, D.V.L PG Y-III

2. History
•Duration
•Thinning
•Shedding
•Pattern of hair loss
•Diffuse
•Localized
•Associated symptoms
•Itching
•Pain
•Burning
•Present health and medical history
•Drug history
•Nutritional history
•Psychosocial history
•History of hair care practices/use
of hair cosmetics
•Family history

3. Examination
1.Proper patient positioning
2.Overall scalp examination
•Pattern
•Distribution
•Frontal hairline: integrity and
density
•Hair color
•Hair length
•Eyebrows and eyelashes
3. Close up examination
•Scarring vs. nonscarring
•Scalp epidermal changes
•Erythema
•Hypo-/hyperpigmentation
•Scales/crusts
•Papules/pustules
•Hair tufting
4. Hair pull test
5. Hair card test
6. Tug test

4. Hair shedding
Hair coming out by the roots
•Telogen effluvium
•Alopecia areata
•Pattered hair loss
•Drugs
•Loose anagen syndrome
Hair breakage
•Tinea capitis
•Trichotillomania
•Improper hair care practices/hair
care cosmetics
•Structural hair shaft disorders
•Anagen effluvium

5. Complaints
•Hair doesn't grow long/ never had a haircut
•Unusual appearance /texture
•Suddenly started breaking
•Complete cessation of hair growth
•When did the problem first start?
•Are there any problems with nails or teeth
•How does the patient dress/style the hair? Brushing technique,
frequency of shampooing, use of heat and chemicals.

6. •Assess its overall appearance, including luster, curl, and color.
•Determine whether the abnormality is focal or diffuse.
•Perform a pull test (Sabouraud sign), which consists of grasping tufts of 20 to 60
hairs between the index finger and thumb and gently pulling on these in different
areas of the scalp. The test is positive when more than 10% of the hairs come out.
•Perform a tug test, which consists of holding a tuft of hair between the fingers
several centimeters from the root and tugging it to detect the presence of fragile
areas.
•Examine the scalp.
•Use noninvasive tests such as photography and trichoscopy to complement the
physical findings.
•In selected cases, use semi-invasive tests such as trichogram analysis, optical
microscopy, and electron microscopy.
•Determine the need for a scalp biopsy where appropriate

8. Inheritable hair shaft disorders and syndromic
associations
1. Pili annulati.
2. Uncombable hair : Uncombable hair
syndrome.
3. Wooly hair : Naxos disease, Carvajal
syndrome, Diffuse partial woolly hair,
Woolly hair nevus, Wooly hair syndrome
(with increased skin fragility) .
4. Curly hair : Costello syndrome, Noonan
syndrome, CHAND syndrome.
5. Trichorrhexis invaginata (TI) : Netherton
syndrome, Monilethrix.
6. Pili torti : Bjornstad syndrome, Menkes
kinky hair syndrome, Crandall syndrome.
7. Trichorrhexis nodosa (TN) :
Trichothiodystrophy, Argininosuccinic
aciduria, Citrullinemia.

9. HAIR CARD TEST
•8 * 12 cm piece of paper
•White on one side and black on
other side.
•Place the card on the scalp and
against the hair shafts in the
affected area.
•Broken hairs or regrowing
hairs??

10. HAIR PULL
TEST
•Affected area- (50-60) hairs
•Pull along the hair shafts
•4 different regions
•prerequisite?
•More than 5/6 hairs pulled
out(10%)

11. TUG TEST
•hold the hairs several centimeters
from the hair tip and then tug at the
ends.
•If the hair is fragile, short 2–4-mm
hair fragments will break off easily
•the distal ends of hairs, against a
piece of paper of contrasting color,
assist the visualizing of the blunt
tips characteristic of broken or cut
hairs.

12. HAIR MOUNT
•Asses hair bulb and shafts using
light microscopy.
•HAIR BULBS: epilated hair roots
placed on a glass slide . Add a
mounting medium. Add cover slip
•Anagen vs Telogen?
•HAIR SHAFT: bubbles,
irregularities, twisting, fractures

13. TRICHOSCOPY
•Magnified observation of: hair shafts, hair follicle openings, perifollicular
epidermis, blood vessels.
•Normal terminal hair: uniform thickness, color throughout the length.
•Vellus hairs: lightly pigmented, measure < 3 mm in length and < 30 microns
in thickness.
•Regrowing hairs: darkly pigmented, straight with pointed ends

15. Phases of
hair cycle
•Anagen (growth phase)
•Catagen (regression phase)
•Telogen (resting phase)
•Exogen (shedding phase)
•Kenogen (lag phase)
15

16. Types of
hair
Different types of hairs are formed - under the
influence of molecular mediators, hormones, and
advancing age.
Broadly, four different types of hairs are found:
- Lanugo hairs.
- Vellus hairs.
- Terminal hairs.
- Intermediate hairs.

17. 17
LANUGO HAIR : Cover entire fetal skin; Soft, fine; oftenunpigmented; Unmedullated; Shed at fetal age of 32-36 weeks or after birth; Longer than vellus hair.
VELLUS: Latin word ‘Vellus’ = Fleece; Covers most of the body; Thin, diameter less than 0.03mm; Less than 1cm length; Unmedullated and lack melanin; Rooted in upper dermis.
TERMINAL : Large with diameter 0.06mm; Scalp, Beard, moustache, axilla, pubis; Dark, thick, medullated, longer; Only type having medulla consistently; Rooted in subcutaneous tissue or deep dermis.
INTERMEDIATE HAIRS : shows characteristics of both vellus andterminal hairs; Have both medulla and moderate amount of pigment; Androgen responsive.
Hair bulb are situated in the reticular dermis rather than the subcutaneous tissue. seen in the stages of balding (AGA) .
SEBACEOUS HAIR FOLLICLES : Have large multilobed sebaceous glands.

19. Hair shaft
•Medullaà cont, discontinuous or absent
spongy structure with amorphous material
bounding air spaces of various sizes
•Cortexà hard, alpha keratin intermediate filaments
•Cuticleà interlocking flattened cells and inner root
sheath cuticle
- 5-10 overlapping cell layers (350-450nm)
- barrier to physical and chemical insults
-wear and tearà gradual loss , breaking and
lifting of free margins

20. •Upper margin of a high arched, inverted "v" shaped
keratinous zone of the HF.
•Marks the beginning of stem of the follicle.
•Region from where cornification of the viable
keratinocytes can first be recognized.
•Henle's layer and cuticle loses its trichohyalin granules
and cornify fully.
•Huxley's layer starts losing its trichohyalin granules and
begins to cornify.
•Dermatophytic infection of the hair-wherein the fungal
mycellium is unable to descent below the fringe.
20
Adamson’s fringe

21. •Line crossing the widest part of
papilla.
•Upper region: differentiating
cells seen.
•Lower region: undifferentiated
proliferating cells present.
•Demarcates theposition of
melanocytes.
21
Critical line of Auber

23. Structural defects with
increased fragility

24. Monelithrix/Beaded/Necklace hair
•Shaft is beaded and breaks easily
•Elliptical nodes 0.7–1mm apart-separated by
narrower internodes - skittle.
•Widths of the nodes & distances between them
vary between the hairs of an individual and
between members of the same family
•Nodes and some of the internodes -normal
imbricated scale pattern
•Most internodes show longitudinal ridging.
•True monilethrix to be distinguished from
pseudomonilethrix

25. Clinical features
•Variation in age of onset, severity,
expression within a family and course.
•Hair loss or broken hair -follicular
keratoses -the nape and occiput
•Rare-the eyebrows, eyelashes, pubic and
axillary hair and general body hair
affected.
•Course: persists with little change
•Spontaneous improvement possible-
pregnancy and with some medications

27. •Pseudomonilethrix- artefact produced
by tweezers or compressing overlapping
hairs between two glass slides.
•Treatment –
•Avoidance of mechanical & chemical
trauma
•Oral etretinate has been used with
limited success
•Some improve spontaneously after
puberty
•Iron supplementation in cases of iron
deficiency

28. Pili torti
•‘Twisted hair’
•hairs are flattened and at
irregular intervals
•completely rotated through 180°
around their long axis.
•Rotation- 3 to 5 twists before
the shaft normalises

29. Clinical Features
•Normal at birthàchange in first few months.
•Brittle and may break off at a length of 5cm or less
•Or grow longer in areas of the scalp less subject to trauma
•Short, coarse stubble over the whole scalp or circumscribed baldness,
irregularly patchy on occipital.
•Affected hairs have a spangled appearance in reflected light.
•Cosmetic appearance of isolated pili torti -improve greatly with transition
from childhood to early adulthood.

30. Diagnosis:
•Scanning electron microscopy.
•To differentiate between the
distinctive twisting of Pili Torti and
other conditions with partial
twisting- Screening in vivo -
dermoscopy.
•Menkes diseaseàsparse
hairàdifficult to sampleàbest
assessed with light microscopy.

31. Diseases with pili torti and twisted hair
PILI TORTI:
•Menkes Syndrome (XLR)
•Female carrier of Menkes
Syndrome
•Björnstad syndrome (AR)
TWISTED HAIR:
•Basex syndrome
•Pseudomonilethrix
•Tricholithodystrophy
•Anorexia nervosa
•Retinoid hair
•Scarring alopecia
•Tuberous sclerosis Complex

32. TRICHORRHEXIS NODOSA
•“Tricho”-hair, “rrhexis”-breakage, “nodosa”-
knots or bulges
•Distinctive response of the hair shaft to injury.
•Can occur in normal hair-with sufficient degree
of injuryà m/c
•Abnormally fragile hairà trivial injuryà nodes
•Cuticular cells become disruptedàcortical
cells splay out àform nodes
•An extreme form of weathering

33. Injury:
•The trauma of hairdressing-combing, ceramic flat iron use in african hair.
•Hair follicle transplantation
•Scratching àpubic hairs
•Shampooing, brushing
•Sea bathing and sunlight àseasonal summer recurrences
Congenital and hereditary defects:
•Argininosuccinic aciduria
•Biotin deficiency
•Trichohepato-enteric syndrome
•Isolated defect of the hair in some familiesàwolff et al.-‘Trichorrhexis
congenita’

34. Polarized light examination
demonstrates the splayed cortical
fibres radiating from the transverse
fracture in trichorrhexis node

35. Clinical features
•congenital defect of hair shaftàlarge or small portions of the scalp show
only broken stumps à gross alopecia
•trauma à 3 presentations:
1.Distal trichorrhexis nodosa:
- occurs in all races
-discovered incidentally-few whitish nodules - near the ends of scattered
hairs.
-If many hairs are affected-dry, dull or brittle hair.
-more likely in long hair.

36. 2. proximal trichorrhexis nodosa:
-generalized variant àAfro-Caribbean
women.
-universally short and brittle scalp hair
-light microscopy :severe weathering
--a/w follicular degeneration syndrome -
central scarring alopecia in absence of overt
inflammatory process
3. The third clinical form -described by
Sabouraud -rare.
-In a localized area of scalp, moustache or
beard
-some hairs are broken and others show from
1-6 nodules

39. Localized autosomal
recessive hypotrichosis
•Brittle hair à fractures readily
àextensive loss of hair.
•Unusually stiff hair
•Hair microscopy à trichorrhexis
nodosa
•Monilethrix like beading.
•Mutations -dsg4 for the
desmosomal protein desmoglein
4

40. pathophysiology
•Electron microscope: shaft appears normal except proximal 1cm- signs of
abnormal wear and tear.
•At nodes: cuticle bulges and split by longitudinal fissures
•trichoclasis : If fracture occurs transversely through a node àthe end of
hair-small paintbrush.
Polarized light examination -splayed cortical
fibres radiating from the transverse fracture in
a trichorrhexis node

41. Trichorrhexis invaginata
•Aka Bamboo hair
•Ball & socket appearance in which the distal
part of the hair shaft is compressed against the
dilated & cupped proximal shaft
•Invagination is caused by softness in the cortex
in the keratinous zone resulting from
incomplete conversion of sulfhydryl to
disulfide groups

42. •Samples should be cut at the scalp surface
•Light microscopy-best tool
•at least 100 hairs are carefully examined -
before a definite negative is asserted.
•single trichorrhexis invaginata node in a
single hair -conclusive positive
• To assess large numbers of hairs-light
microscope, as electron microscopy will
only allow assessment of small lengths of
a small number of hairs

43. Scanning electron microscopy -focal defects
àtorsion nodules, invaginated nodules
(trichorrhexis invaginata) and trichorrhexis nodosa.
Dermoscopy- difficult to differentiate b/w T. nodosa
and T.invaginata- proximal remnant of an invaginate
node àgolf tee
An invaginate node acting as a
point of weakness in the hair shaft.

44. NETHERTON
SYNDROME
•‘Bamboo hair’, rare, AR.
• features :
-Ichthyosis linearis circumflexa
-‘bamboo hairs’ (trichorrhexis invaginata)
-atopy
-recurrent skin infections
- predisposition to skin malignancy
Netherton syndrome results in fragile hair.

45. Trichoclasis
•Common “ green stick” fracture of the hair
shaft (part of cuticle intact).
•Cuticle is partly stripped in continuity with the
fracture because of weathering & cosmetic
trauma.

46. Trichoschisis
•Clean transverse fracture across the hair shaft
due to absence of cuticle
•Usually seen in Trichothiodystophy

47. TRICHOTHIODYSTROPHY
•“Tricho”-hair, “thio”- sulphur, “dys”-faulty,
“trophe”–nourishment
•Brittle hair with abnormally low sulphur
content
•Neurocutaneous disorder characterized by
diffuse non-scarring alopecia & systemic
defects

48. Clinical features
•Wide range of phenotypic characteristics
•Hair abnormalities inversely
proportional to sulphur content
•Depending on the variant of TTD: the
hair is sparse, short and brittle, but the
degree of alopecia varies considerably.
•Lamellar ichthyosis.
•Dystrophic nails.
•Mental and physical development may
be retarded in some.
Classification
•A: Isolated Hair Defect
•B: A + Nail Dystrophy
•C: B + Mental Retardation
•D: C + Growth Retardation
•E: D + Decreased Fertility
•F: E + Ichthyosis
•G: F + Photosensitivity
•H: G + Neutropenia

49. Pathophysiology
•Brittle hair and weathers readily
•Abnormalities inversely proportional to the sulphur content
•Similar pattern of change -distal segments of african hair subjected to chemical
relaxers.
•Sulphur amino acid reduction à hair abnormality in autism
•With trauma àfracture with a clean transverse break (trichoschisis) or form
nodes resembling trichorrhexis nodosa.
•The hairs are flattened and can be twisted into various shapes – rather like a
ribbon or shoelace..

51. •Polarizing microscopy shows
characteristic alternating dark and
bright zones at regular pattern
showing a “Tiger Tail Pattern”
•Scanning EM reveals severe
cuticular defects and secondary
cortical degeneration

53. Structural abnormalities
without increased fragility

54. Pili annulati
•‘Ringed hair’
•Hair shows alternate light and dark bands
along its length
•In extreme cases -additional fragility àlighter
areas seen with light microscopy àsplit in the
hair cortex.
•Autosomal dominant
•Molecular basis of the abnormalityàunknown
•The genetic defect àchromosome 12q

55. Pathophysiology
•light microscope: the abnormal dark bands alternating with normal light
bands are reversed.
•Bright abnormal bands in reflected light àair spaces in the cortex
•cortical defect detected easier if the hair is mounted in histological
mounting medium -enhances the transmission of light through the hair.
•Dermoscopy-unreliable

56. Clinical features
•Incidental finding-due to spangled appearance.
•Possible association with alopecia areata.
•Fragility - occasionally a presenting feature à longitudinal fracture in the
hair cortexà weakens the shaft àfracture.
• Axillary hair occasionally affected.
DD: Pseudopili annulati -partially twisted shafts have an elliptical
cross-section àimpression of alternating light and dark bands
Prognosis: good àseverity does not increase with age.

58. PILI PSEUDOANNULATI
•Mimics pili annulati
•Bright segments are caused by
reflection and refraction of light by
flattened, twisted surfaces of hair
•Variant of normal hair

59. Wooly hair
•Tightly coiled hair -over all or part of the scalp.
•Normal in african origin.
•Tight coiling, knots and fractures are common.
•Woolly hair in non-african individuals –
generalized/ localised
•The generalized forms -inherited.

60. •Hair microscopy -nonspecific
features àwoolly, stiff hair
phenotype.
•grooves, partial twists, irregularity
of bore and sometimes features of
trauma.
•When hair shaft has an irregular
shape and is stiffer, it is more
prone to damage.
• electron microscopy:
-excellent for revealing great detail
in a small number of hairs

61. Variants:
•Autosomal dominant woolly hair:
-Naxos disease
-Carvajal disease
•Woolly hair naevus:
-circumscribed patch of hairàaltered colour
and texture
-fine in infancy, becoming coarser with
age(puberty)
-a/w melanocytic /epidermal naevi
-Associated ocular and auditory defects,
digital abnormalities and precocious
puberty

62. •Acquired wooly hair:
-heterogeneous group.
-m/c patterned hair loss (acquired progressive kinking of hair)
-drugs -valproate and retinoids

63. Uncombable hair syndrome
•‘Spun-glass hair‘, ‘Cheveux incoiffables‘ ,’Pili
trianguliet canaliculi’
•Described by dupré and bonafe
•Autosomal dominant
•Acquired- chemotherapy, valproate
•Noticed at 3 months to 12 years age.
•Normal in quantity, length
•With wild, disorderly appearance & silvery Blonde
colour
•Cannot be controlled with combing

64. Pathophysiology
Light microscopy : rigid hair shaft: the
triangular cross-section and
longitudinal grooving.
•Twisting àstiffness to a minor
degree.
Scanning electron microscopy: of
selected hairs
•pili canaliculi -all cases,
•pili trianguli -majority
•pili torti -few.

66. DDs:
•loose anagen syndrome
•a/w neurofibromatosis I
•acquired form- following chemotherapy
-Or in a/w sodium valproate
Management:
•No known treatment
•oral biotin therapy.
•features often diminish with adulthood.

67. Loose anagen hair
•Loosely anchored and easily pulled from the scalp
•The majority -fair-haired children, aged 2–9 years, mostly
girls.
•Also Egypt and India in children with darker skin and hair.
•hair -typically slightly unruly, of uneven length and patchy in
quality
•history of not growing properly and never needing cutting.
•Variable clinical picture–stiff, uncombable hair and others of
excessive shedding of hair.
•Patchy alopecia- due to mild hair pulling ( DD- Alopecia
Areata)

68. •Hair pull test: easily and painlessly plucked
•Microscopy : ruffling of the cuticle adjacent
to the anagen bulbà‘floppy sock’
•The hair shaft may have twists and grooves,
•angular in cross-section
•root sheath is absent or small everted
remnant
• Scalp biopsy : irregular keratinization
dyskeratosis of the root sheath cuticle cells

69. •if the hair is not loose on the hair-pull test-the diagnosis can not be made.
•Conversely, if the hair is loose- DDs: Telogen effluvium , Alopecia areata.
•Histological examination: premature keratinization of the inner root sheath
layers of Huxley and Henle.
•Trichograms: show 98–100% anagen hairs.
•Keratin K6irs-inner root sheath keratin à might control manifestations of the
disorder.
•Management : gentle hair grooming , reassurance that the defect usually
resolves spontaneously with age.

70. Trichostasis spinulosa
•A common disorder of the hair follicles that
clinically gives the impression of follicular
keratosis
•Follicles are filled with funnel-shaped horny
plugs within which are bundles of vellus hairs
•Hairs are round at their proximal ends and are
shredded distally

71. Clinical features
•resemble comedones
•m/c on nose, forehead and cheeks, or the face may be spared and the nape, back, shoulders, upper arms and chest may be affected.
•The number of follicles affected varies greatly.
Dermoscopy : comedo-like lesions are prominent and in some cases a tuft of hairs may be seen projecting through the horny plug.
Management:
•topical retinoic acid- treatment of acne
•Depilatory wax
• specialized cleaning pads
•variety of laser treatments

72. •affected follicles -50 vellus hairs
embedded in a keratinous plug.
•mild perifolliculitis is often present.
•Follicles may contain Malassezia yeasts
and Propionibacterium acnes
•DD: ‘multiple hairs’ of Flemming–
Giovannini in which up to seven hairs
grow from a composite papilla with a
common outer root sheath.

73. Pili multigemini
•uncommon developmental defect of hair
follicles that fuse
•multiple hairs from a composite follicular
structure emerge through a single
pilosebaceous canal.
•different from where separate follicular bulbs
generate hairs that fuse in the infundibular
region -emerge from a single opening.

74. Clinical features
•mainly on the face- along lines of the jaw
•Tufts of hair may be seen emerging from a
few or many follicles.
•Incidental finding
•but patient may complain of recurrent
inflammatory nodules-scars.
Treatment
•If the hairs are plucked, they regrow
•A single report of ablation after three
treatments with a ruby laser may indicate
that this is a therapeutic option

75. Weathering
•cuticular damage and secondary cortical
breakdown from root to tip before being
shed during the telogen or early anagen
phase of the hair cycle.
•damage -combing, brushing, bleaching,
UV radiation and permanent waving, Hair
knotting and braids.
•Scalp hair-long anagen phase àmore
frictional damage and cosmetic
treatmentà More deep cuticular and
cortical degeneration

77. TRICHONODOSIS
•“Tricho”- hair, “nod”- knot,
•Common cause : combing trauma
•Induces knots where the shaft
•may break
•Seen in short and flat curly hairs

79. Trichoptilosis (split hair)
•Longitudinal splitting of the distal end of the
hair shaft
•m/c in long hair and African origin
•Not pathognomic for any alopecia type, can be
seen in healthy individuals
•Occurs due to mechanical or chemical trauma

80. Bubble hair
•change caused by heat-faulty hairdryer or
tongs at high temperature àfocal damage
•damp hair àcontributory factor
•light and electron microscopy: bubbles are
gas-filled rather than containing fluid.
•assessment is enhanced by the use of DPX
fluid slide mountant by diminishing reflection

83. references
•Bhat YJ, Trumboo T, Krishan K, Hair shaft disorders
in children – An update. Indian Dermatol Online J
2023;14:163-71.
•Giacaman A, Ferrando J. Claves diagnósticas en
displasias pilosas I. Actas Dermosifiliogr.
2022;113:141---149
•Rooks- 9th Edition
•IADVL- 5th Edition

84. Thank you