Pathogenesis of monilethrix: computer stereography and electron microscopy

The plucked hairs and biopsied hair follicles of the scalp were obtained from a female patient with monilethrix. By scanning electron microscopy, the plucked hairs showed a typical moniliform feature composed of alternated nodes and internodes. By computer stereography, reconstructed three-dimensional models of in vivo hair structures showed that the diameter of hair shaft was partially reduced in the keratogenous zone and that the reduction was severe in the hair cortex and cuticle layers but mild in the inner root sheath. By transmission electron microscopy, a significant degeneration of hair matrix cells was found, and a zig-zag disarray of cortical tonofibrils and invaginations of the hair cuticle cells into the cortex were noticed in the suprabulbar portion. In some hairs, the hair bulbs showed no degeneration, but a degeneration of cortical cells and invaginations of hair cuticle were seen in some portions in the developing zone of the cortex. This suggests that not every hair matrix is damaged in a synchronized fashion, but individual hairs are affected independently. Furthermore, in all the hair and hair follicles examined, cytoplasmic vacuolations were always seen in the various layers, and abnormal formation of tonofibrils was often observed in the cortex. In monilethrix, a cell abnormality may inherently be present in the hair tissue and, when such abnormality occurs severely, the cortical cells are particularly affected in the hair matrix. This seems to result in a decrease in number of cortical cells and thinning of the hair shaft.     

Ultrastructural study of acquired pili torti-like hair defects accompanying pseudopelade

Acquired structural hair defects are caused by various physical and chemical manipulations. Plucked hairs and hair follicle biopsy specimens of pili torti-like hairs that arose from pseudopelade scalp were studied. In scanning electron microscopy, the hair shafts had a segmental pili torti-like appearance, accompanied by oblique or longitudinal grooves and ridges. In light microscopy, the hair follicles showed an asymmetric hair bulb and inner root sheath, and a shortened keratogenous zone within sclerosing fibrous connective tissue. In transmission electron microscopy, the numbers and thickness of the hair cuticle cells were different on the opposite sides of the hair shaft. The hair cuticle was irregularly shaped and formed asymmetric waves. The tonofilaments in the hair cortex ran almost parallel to the hair axis. From these findings, it was clear that the grooves and ridges were produced by the deformed hair cuticle and cortex, whose shapes were modulated by the asymmetric inner root sheath. This asymmetry most likely resulted from a dysfunctional dermal papilla, which was affected by fibrosis. The pili torti-like appearance appeared to be caused by the grooves and ridges that ran obliquely on the hair shaft surface.     

Ultrastructural study of exclamation-mark hair shafts in alopecia areata

The prime diagnostic feature of acute alopecia areata is the presence of exclamation mark hairs. These characteristic hairs fracture at their distal end and taper proximally towards the scalp, giving them the appearance of an exclamation mark. Hair morphology was studied in 8 patients with untreated acute alopecia areata and 3 normal adults without hair loss. Light microscopy, transmission and scanning electron microscopy revealed distinct structural differences in the distal end of hairs compared with the remainder of their length and with normal hair shafts. Transverse sections of hairs just below the frayed brush-like tip often displayed asymmetrical cortex disintegration. One side was compact and homogeneous while the other was deeply fissured and/or broken up into discrete heterogeneous-staining fragments of cortical, stratum corneum and cuticular components in addition to apparently degenerate cortex. Many exclamation mark hair tips lacked cuticle and had irregular profiles. Melanin was found in cortical and medullary fragments at the tip, although it was absent in the more degenerate forms of cortex. More proximal sections of these pathognomic telogen hairs revealed nearly normal hair shaft ultrastructure.     

Hair in psoriasis: a prospective, blinded scanning electron microscopic study

We examined hairs from psoriatic plaques by scanning electron microscopy, and compared the morphological changes in the hairs with those from the corresponding nonlesional skin of the same patients and those from healthy subjects, in a observer-blinded prospective study. Micropits or macropits (sharply demarcated defects on the cuticle < 0.5 µm or > 0.5 µm, respectively, in diameter), dystrophy (areas showing generalized roughness and ragged appearance of the cuticle), upturned edges of cuticular cells, transverse and longitudinal fissures were seen in varying frequency in all three groups. Micropits were significantly more frequent in the lesional hair compared with hair from the nonlesional area and controls. Dystrophic changes were significantly more severe in lesional hairs compared with hair from the nonlesional area. Upturning of cuticular edges was more frequent (but not significantly so) in hair from psoriatic plaques. The presence of micropits and hair dystrophy could contribute to the thinning and loss of hair in the psoriatic plaques.     

Cheveux incoiffables—diagnostic, clinical and hair microscopic findings, and pathogenic studies

Three possible mechanisms of the hair shaft abnormality in cheveux incoiffables have been investigated in nine patients. Cheveux incoiffables hairs were found to exhibit a normal distribution of cystine-rich protein within both the cuticle and the cortex, as determined by silver methenamine ultrastructural cytochemistry. Resistance to stretching, at 65% relative humidity and constant temperature, was similar to normal controls. Resistance to bending forces was also assessed, and was equivalent in both groups. On scanning electron microscopy, all patients with cheveux incoiffables demonstrated longitudinal grooving of the hair shaft, and the hairs were triangular or heart-shaped in cross-section. In addition, there appeared to be minimal cuticular weathering. Even hairs of 20–30 cm length showed only minimal cuticular and cortical weathering, compared with normal hair shafts of similar length and diameter. It is possible that the reduced progressive weathering renders the hair shaft more rigid, and could serve to explain the ‘stand on end’ appearance of the hair which is typical of this condition. However, the characteristic cross-sectional shape of the hair shaft in cheveux incoiffables may render it more rigid and resistant to bending forces. This latter theory has yet to be fully investigated.     

Scanning electron microscopy comparing exclamation mark hairs in alopecia areata with normal hair fibres, mechanically broken by traction

A scanning electron microscope was used to compare the distal ends of exclamation mark hairs from alopecia areata patients with the fracture surface of normal hair fibres, mechanically broken by traction. The exclamation mark hairs shows minimal damage to the cuticular cell pattern of the hair shaft. Where the cuticle was absent, cortex and medulla showed low-density features fanning out into a fringe-like structure at the distal ends. The fracture surfaces of normal hair fibres, mechanically broken by traction showed a markedly abnormal cuticular scale pattern, whereas the features of cortical and medullary tissue were normal. These morphological differences between the fracture surface of exclamation mark hairs and normal hair fibres, mechanically broken by traction, may enhance our understanding of the pathogenesis of alopecia areata.     

Abnormal hair shafts in psoriasis on scanning electron microscopy

Summary.— We have examined hairs from psoriatic patients by scanning electron microscopy and compared them with hairs from normal subjects. Micropits were seen in normal hair cuticle cells and in those from psoriatic subjects. Their significance is unknown. Dystrophic changes of these cells are associated with the psoriatic diathesis, occurring significantly more often in hairs from unaffected as well as from affected skin of patients with psoriasis compared with controls. We confirm previous observations that the hairs growing from psoriatic plaques are significantly thinner than those growing elsewhere on psoriatic subjects and than those of normal controls. These studies confirm and expand previous evidence of hair shaft abnormalities in psoriasis.     

Natural progression of male pattern baldness in young men

Twenty-six men who presented with male pattern baldness (androgen-dependent alopecia), were quantitatively evaluated for scalp hair variables and compared with 13 age-matched controls. Compared to controls, significant mean differences for hair variables were found in the frontal-vertex area, while in the occipital area, a reduction in total hair density (hairs/cm2) was the only significant (P less than 0.05) finding. A large proportion (48.5%) of meaningful hair (non-vellus hair) was less than or equal to 40 mm in length, yet had diameters similar to hairs growing much longer. In controls, these hairs accounted for only 12.2% of the total population. Compared to baseline, mean values from the frontal-vertex area of subjects with androgen-dependent alopecia were significantly lower for total hair density, meaningful hair density (non-vellus hairs/cm2) and percentage of hair in the anagen growth phase, 12 and 24 months later. During this time, total hair density decreased by 6.5% after 12 months and by 11.9% after 24 months. Similarly, meaningful hair density declined at 12 months by 10.8% and by 22.7% after 24 months. No change in any hair variable was detected in controls after 12 or 24 months. Our findings suggest that medications capable of maintaining the existing hair population should be regarded as effective treatments for this condition. Left untreated androgen-dependent alopecia progressively deteriorates. The induction of non-vellus hairs less than or equal to 40 mm in length to grow longer, would substantially improve the aesthetic profile without the need to generate new hair.     

Green hair: clinical, chemical and epidemiologic study. Apropos of a case

A 36-year-old blond woman suddenly developed green tinted hair following exposure to swimming pool water. This was the first green discoloration she noticed, although she had been an active swimmer for several years. Clinical examination showed green tinting toward the distal ends of the most superficial strands of hair. The copper content of plucked green hair measured by atomic absorption was elevated to 3,900 ppm and the copper concentration in water from the swimming pool implicated was 9.94 ppm. Following renewal, the latter value decreased to 107 ppb. Hair examination under polarizing light was normal, and a scanning electronmicroscopic study of hair samples showed a total loss of cuticle with micropits scattered over the hair shaft surface mimicking a "dead tree trunk". Epidemiological investigations showed that the increased copper content of swimming pool water was due to added algaecides without adequate replacement of the water. Hair damage resulting from repeated waving and/or bleaching of the hair turns out to be an important factor in the deposition of copper by inducing an increase in keratin content of cysteic acid and related anionic sulfonate groups which participate in copper adsorption. On the ocassion of this case-report, epidemiological data published by others, together with the chemical and therapeutic aspects of green hair are reviewed.     

婴儿头部念珠菌病的临床与实验室研究

报道３６例婴儿头部念珠菌病的临床与实验室研究结果。本病主要临床特点是：发病年龄均为婴幼儿。初诊时皮损绝大多数为结痂，仅２例呈小脓疱。局部应用抗真菌剂有效，愈后不遗留瘢痕。取菌痂作透射电镜检查可见菌丝和孢子。扫描电镜观察可见菌丝和孢子围绕毛发，毛干变细并有裂隙。应用白念珠菌作５个年龄组头发的体外感染试验，新生儿头发的毛小皮和皮质于１６～２０周被破坏。故我们认为念珠菌可侵犯毛干。     

Morphological analyses in fragility of pili torti with Björnstad syndrome

Pili torti is an extremely rare hair phenotype characterized by short length of hairs with hair shafts being easily broken. However, the mechanism of fragility in pili torti is unclear. In this study, we examined the underlying morphological features responsible for pili torti formation using transmission electron microscopy (TEM). We used pili torti samples from a patient with Björnstad syndrome and normal hairs from a healthy subject as a comparison. The macroscopic morphological features of the samples agreed with the results of a previous study showing that pili torti is twisted, flattened, thin and with partial trichorrhexis. Young's modulus of the samples was lower than that of normal hairs. Because the cross‐sectional area of the pili torti samples was also smaller than that of normal hairs, it was clarified that the tensile strength of pili torti is 2.1‐times lower than that of normal hair. Assessment of morphological features by TEM showed that the cuticle layers of the samples had wavy shapes with different thicknesses. Additionally, the cortex in the samples showed loose keratin intermediate filaments (IF). Our results suggested that these abnormalities in pili torti had already occurred below the infundibulum. Thus, the weakness of pili torti in tensile strength is thought to result from loose IF because of dysformation of disulfide bonds.     

头癣病发的电镜观察

本文报告由许兰氏黄癣菌、紫色癣菌和铁锈色小孢子菌感染引致3型头癣病发的电镜观察结果.扫描电镜显示毛发鳞片破坏,有不同大小和形态的孔洞和沟裂,以及毛干表面密集卵园形孢子.透射电镜显示许兰氏黄癣菌的真菌细胞位于毛髓质和毛皮质;紫色癣菌的真菌细胞位于毛皮质外层;而铁锈色小孢子菌的真菌细胞位于毛小皮内,后者不同于光学显微镜所见.因此,提示铁锈色小孢子菌的感染毛发可能属于发内一外感染.     

Hair casts due to a deodorant spray

A 7-year-old girl presented with itching and greyish-white sleeve-like structures in her hair. After ruling out other possible causes for the symptoms, such as nits and dandruff, it was determined that the patient was affected by hair casts. These are small cylindrical structures resembling louse eggs that encircle individual scalp hairs and are easily movable along the hair shafts. It was concluded that she had induced the condition through misuse of a deodorant body spray. Scanning electron microscopy combined with electron dispersive X-ray analysis (X-ray microanalysis) of the hair casts showed the chemical nature of the structures. Some elements present in the composition of the ingredients of the deodorant spray, such as aluminium, chlorine, silicon, magnesium and carbon, were also present in this uncommon type of hair casts.     

Pathogenesis of pili annulati

Summary Plucked scalp hairs and hair roots of pili annulati were examined to understand their pathogenesis. Stereoscopic examinations of hairs in transmitted light and/or reflected light and light microscopic surveys of the cross-sections of hairs confirmed that the cortical empty spaces appeared to be responsible to the unique dotted shiny appearance of the hairs seen by the unaided eyes under a refracted light. By transmission electron microscope, small vacuoles and dense bodies were observed in the cytoplasm of the differentiating cortical cells; subsequently, with increasing number of tonofilaments, an uneven distribution of free ribosomes occurred and abnormal spaces containing fine granular substances were formed in the cytoplasm of the cortical cells. Occasionally, extremely large cortical trichohyaline granules were found. In the keratinized hair, irregular empty spaces were present in the cortex of the abnormal hair segments. Histochemically, the keratinized cortex of the affected hairs always had more residual SH groups than the controls. Pili annulati may be a disorder of protein metabolism involving a partial dysfunction of cytoplasmic ribosomes, resulting in a lack of cortical keratin formation.     

Weathering of hair in trichothiodystrophy

The structure of hairs from three patients with sulphur-deficient hair, trichothiodystrophy, has been studied by light, plane-polarizing and scanning electron microscopy. Severe cuticular and secondary cortical degeneration was evident along almost the entire length of the hair shaft, with cuticle loss, trichorrhexis nodosa formation and trichoschisis. The severity of these changes varied between patients. The role of the cuticle in protecting hair from environmental damage is discussed.     

PATHOGENESIS OF GENETIC HUMAN HAIR DISORDERS

Several distinct morphological abnormalities of hair were discussed. Most of congenital hair defects appear to be related to anatomic (defective cuticle formation) and biochemical (reduced sulfur content) properties. The major structural hair abnormalities include defects in the cuticle, cortex and medulla. Our studies have revealed that there were defects of the cuticle in each case of a major structural hair defect.     

Woolly-hair nevus: a case report and study by scanning electron microscopy

Abstract: Woolly-hair is a congenital defect that produces a localized patch of lightly colored, curly scalp hair. Scanning electron microscopy of the abnormal hairs demonstrates twisting of the hair shaft and abnormal cuticle formation.     

Loose anagen syndrome as a severity factor for trichotillomania

Loose anagen syndrome (LAS) is a condition of childhood where anagen hairs are easily and painlessly extracted. The condition is due to poor adhesion between the cuticle of the hair shaft and the inner root sheath. A 4-year-old girl presented with patches of hair loss and a clinical diagnosis of trichotillomania was made. A hair pull test extracted multiple hairs easily and painlessly. Light microscopic examination was consistent with LAS. A biopsy was performed, which showed features of trichotillomania. However, on request the child did not display sufficient dexterity to pull out her own hair. It was subsequently determined that her hair loss was likely to be due to a third person plucking out her hair. It appears that in this case the LAS was not the cause of her hair loss, but rather acted as a severity factor for trichotillomania by proxy in that the lack of pain on plucking the hairs removed the principle deterrent.     

In-situ imaging mass spectrometry analysis of melanin granules in the human hair shaft

The elemental composition of melanin granules and other components of the hair shaft was determined by multi-isotope imaging mass spectrometry, a method with unique advantages for the visualization and quantification of stable isotopes and the elemental composition in study of the fine structure of biologic samples. We mapped and quantified the chemical composition of hair cross-sections using secondary ions generated from naturally occurring 16O, 12C14N, 32S, and 34S with a maximum lateral resolution of 35 nm. Based on these elemental maps of unprecedented resolution we obtained simultaneously the chemical fingerprints and the structural features, such as cuticle, melanin granules, the macro fibrils of the cortex, and small sulfur-rich domains in the medulla, in the hair cross-section. We found an intriguing distribution of 16O, 12C14N, and 32S in melanin granules that we interpret as a highly anisotropic pattern of oxidation.     

A girl with loose anagen hair syndrome and uncombable, spun-glass hair

A 4-year-old girl presented with a 2-year history of scalp hair that had an odd texture, was difficult to manage, tended to "stick out" from the scalp, and was irregular in length. A hair pull test revealed that hairs could be easily and painlessly extracted. Light microscopic examination of the hair demonstrated anagen hairs with a ruffled cuticle and distorted bulb as well as an unusual undulation and grooving of the shafts. These findings are consistent with both loose anagen and uncombable hair syndromes. The occurrence of both syndromes in the same patient seems unlikely, and we propose that our patient has loose anagen hair syndrome with features resembling uncombable hair syndrome.