Diagram of an anagen hair follicle.
(a) Surface view of weathered cuticular scales in the distal portion of the hair shaft. (b) Surface view of undamaged cuticular scales in the proximal...
The hair cycle. (From Olsen 1994. Reproduced with permission of McGraw‐Hill.)
Trichoscopic images. (a) Yellow dots in alopecia areata. (b) Black dots and broken hairs in alopecia areata. (c) Variation in hair fibre diameter in f...
Hamilton–Norwood scale for grading male pattern hair loss (From Norwood 1975 [ ]. Reproduced with permission of Wolters Kluwer Health.)
Acute telogen effluvium.
Idiopathic chronic telogen effluvium.
An early anagen follicle in alopecia totalis, showing vacuolation in the hair matrix epithelium around the upper pole of the dermal papilla.
Alopecia areata showing regrowth of hair at sites of intralesional corticosteroid injection (triamcinolone acetonide).
Discoid lupus erythematosus. (a) Low‐power photomicrograph showing follicular plugging, superficial and deep perivascular and periappendageal lymphocy...
Folliculitis decalvans showing active pustulation and scarring.
Histology of trichotillomania showing fragmentation of the hair shaft.
Trichorrhexis invaginata in Netherton syndrome.
Trichothiodystrophy showing alternating bright and dark zones under a polarizing microscope. (Courtesy of D. Van Neste, Brussels.)
Plucked anagen hair in the loose anagen syndrome, showing a vestigial root sheath and a ruffled cuticle.
Congenital hypertrichosis lanuginosa. (Courtesy of Dr Partridge, Leamington, UK.)
Facial hirsutism: in this case it was not associated with any systemic disease or detectable biochemical endocrine abnormality.
Grouping of hairs in follicular units on the human scalp. In some groups, multiple hairs emerge from a single follicular opening.
Cross‐section through hair shaft showing cuticle layers (Cu) surrounding the central cortex (Co). Transmission electron micrograph, silver methenamine...
Scalp hair follicle in the anagen II stage of development. The club hair from the previous cycle is still present within the follicle. (Courtesy of D...
Biopsy – scarring alopecia protocol.
Ludwig scale for grading female pattern hair loss. (From Ludwig 1977 [ ]. Reproduced with permission of John Wiley.)
Diffuse alopecia in association with hypothyroidism.
‘Porrigo decalvans’ (alopecia areata). Plate XL from Thomas Bateman's atlas Practical Synopsis of Cutaneous Diseases , 1819.
Alopecia areata. (a) Patch of alopecia areata showing broken ‘exclamation mark hairs’ towards the margins. (b) Close‐up of exclamation mark hairs. (c)...
Lichen planopilaris. (a) Low‐power photomicrograph showing follicular plugging and a periappendageal inflammatory infiltrate. (b) Base of the hair fol...
Positive linear immunofluorescence to IgG: the lupus band test. (Courtesy of Dr G. Mason, Melbourne, Australia.)
Trichotillomania showing a characteristic ‘tonsure’ pattern with the scalp margin hair spared.
Monilethrix with swollen (node) and narrow (internode) fluctuations in the hair bore.
Netherton syndrome. (a) An invaginate node showing partial twisting of the hair at the upper pole. (b) An invaginate node acting as a point of weaknes...
Pili annulati. (a) Hair shaft by transmitted light showing an abnormal dark band (central part) caused by multiple cortical air spaces. This correspon...
Focal loss of the cuticle in a weathered hair.
Lumbosacral hypertrichosis (‘faun tail’), here associated with diastematomyelia.
Human anagen follicle, showing pigment donation to the hair cortex. There is pigment incontinence in the dermal papilla. Masson–Fontana stain.
Longitudinal section through the suprabulbar region of an anagen follicle showing the keratogenous region of the hair shaft (HS). The inner root sheat...
Cross‐section of transformed cortical cells of human hair. The relatively translucent filaments, set in a more dense sulphur‐rich matrix, appear as co...
Human hair follicle in mid‐catagen. There is a prominent glassy membrane surrounding the regressing epithelial column. The dermal papilla has rounded ...
Biopsy – non‐scarring alopecia protocol.
Pattern of frontal hair loss in women with androgenetic alopecia. Stage 1 is normal.
Acquired zinc deficiency resulting from prolonged parenteral feeding and inadequate zinc supplementation.
Lymphocytic inflammatory infiltrate surrounding an anagen hair bulb in alopecia areata.
(a) Sparing of white hairs in a patch of alopecia areata.(b) Regrowth of hypopigmented hair in alopecia areata.
(a) Scarring alopecia caused by lichen planus showing active lesions.(b) More advanced lichen planus showing follicular plugs and scarring.
Discoid lupus erythematosus showing scarring alopecia with scalp erythema and follicular plugging.
Traction alopecia from braiding.
Monilethrix on the nape of the neck showing follicular keratoses and short, broken hairs.
Localized autosomal recessive hypotrichosis due to a dsg4 mutation.
Woolly hair naevus.
(a) Knotting of single and multiple hairs contributes to hair shaft trauma. (b) Braiding damages the hair shaft cuticle.
Facial hypertrichosis in porphyria cutanea tarda.
Rapid greying of the hair caused by alopecia areata. (a) A patient with slight greying of the hair, and (b) the same patient shown 1 week later. (Cou...
Anagen hair bulb. Co, hair cortex; Cu, hair cuticle; DP, dermal papilla; DS, dermal sheath; He, Henle layer; HM, hair matrix; Hu, Huxley layer; IRSCu,...
Exploded view of the major structural components comprising a human hair fibre. Pigment granules that are normally dispersed throughout the cortex are...
Bactrian camel in a spring moult.
(a, b) Orientation of the punch biopsy in the direction of hair growth.
Histopathology of female pattern hair loss. (a) Increase in telogen forms – three of five follicles in a follicular unit are in telogen. (b) Follicula...
Hair loss and photosensitivity caused by systemic lupus erythematosus.
Proposed pathodynamic changes in alopecia areata. An inflammatory attack on anagen follicles precipitates follicles into telogen. Follicles re‐enter a...
An organized pattern of pitting present on all fingernails 8 months prior to the onset of alopecia areata. The pits are highlighted with mascara.
Frontal fibrosing alopecia showing scarring alopecia affecting the frontal hairline with follicular erythema and scale.
Pseudopelade of Brocq.
Traction alopecia in a Sikh boy.
Trichodysplasia spinulosa histopathology. (a) Aberrant keratinization of the inner root sheath. (b) Positive immunohistochemical staining for polyomav...
Pili torti. (a) Light micrograph showing 180° twists. (b) A 6‐month‐old boy with Menkes syndrome. (c) A 27‐year‐old woman with no personal or family h...
Trichorrhexis nodosa. (a) Polarized light examination demonstrates the splayed cortical fibres radiating from the transverse fracture in a trichorrhex...
Uncombable hair syndrome. (a) The triangular cross‐section of the hair contributes to its stiffness. (b) Light microscopy revealing grooving when usin...
Appearance of normal scalp hair after exposure to a naked flame. Bubbles form within the cortex.
Localized hypertrichosis at the site of underlying panniculitis.