Woolly‐Hair Nevus: A Case Report and Study by Scanning Electron Microscopy

“…Irregular, partial twists of the hair shaft accompanied by slanted grooves along the shaft have been reported in acquired progressive kinking of the hair (5), wooly‐hair nevus (6,7), uncombable hair syndrome (8‐10), and Netherton's syndrome (11). Irregular twists are common in many syndromes with other hair defects.…”

Section: Discussionmentioning

confidence: 99%

Ultrastructural Study of Acquired Pili Torti‐like Hair Defects Accompanying Pseudopelade

Sakamoto

Ito

Saito

2002

The Journal of Dermatology

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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.

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“…The pigmentary or epidermal nevi are usually on the neck, arms, or trunk, and not on the scalp. In general, it is an isolated finding, but woolly hair nevus has been reported to occur with neurological defects, ocular abnormalities, 34 bone disorders, and other mesodermal defects 33 . Hair mount of woolly hair does not have any distinguishing findings 35 .…”

Section: Congenital Hair Shaft Disorders Without Increased Fragilitymentioning

confidence: 99%

“…The woolly hair can grow at a normal rate 32 or slower 22 than normal hair. Woolly hair nevus typically presents at birth or develops before 18 months of age 33 . In about half the reported cases, woolly hair nevus is associated with linear nevi.…”

Section: Congenital Hair Shaft Disorders Without Increased Fragilitymentioning

confidence: 99%

A practical, algorithmic approach to diagnosing hair shaft disorders

2010

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The hair shaft is a unique structure composed of an inner cortex and a protective outer cuticle. Any defects in this normal structure due to genetics or the environment can lead to variations in physical properties. Thus one should suspect a hair shaft disorder if a patient presents with an abnormality or change in hair texture, appearance, manageability or ability to grow hair long. A key feature of the clinical evaluation is to determine whether there is hair breakage (increased fragility) by looking for broken hairs and performing a tug test.Once this determination is made, an algorithmic approach can be used to narrow the differential diagnosis: hair shaft disorders with and without fragility. A hair mount along with other directed questions and examination will almost always allow the clinician to make an in-office diagnosis. Common case scenarios, photographs, and practical tips are provided to illustrate the use of this algorithmic approach in the diagnosis of hair shaft disorders. We have also included a summary of the molecular defects where known, which can be helpful in providing a correlation with clinical findings, in counseling patients, and potentially offering treatment options.

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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.

Cited by 21 publications

References 15 publications

Woolly hair nevus: A rare entity

Woolly hair nevus: A rare entity

Ultrastructural Study of Acquired Pili Torti‐like Hair Defects Accompanying Pseudopelade

A practical, algorithmic approach to diagnosing hair shaft disorders

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