Pili annulati with fragility: Electron microscopic findings of a case

Transmission electron microscopy of pili annulati

BACKGROUND

Little is known about the ultrastructure of pili annulati.

OBJECTIVES

To examine with transmission electron microscopy affected hairs of a family, whose diagnosis had been confirmed in five individuals with scanning electron microscopy, which showed surface undulations with "curtain-like" folding of the hair cuticula and to compare the findings with normal control.

METHODS

Hairs of two affected patients and one control were embedded in resin and cut lengthwise to produce ultra-thin sections.

RESULTS

The normal hair showed a parallel arrangement of dark lines associated with less electron-dense wide bands. Small cavities could be observed, mostly in the dark lines, affected hairs had a large number of cavities, associated or not with the insertion of melanosomes and loss of parallelism of the dark lines. Higher magnification showed a significant loss of this parallelism, resembling "wood grooves". Widened dark lines were observed in some areas.

STUDY LIMITATIONS

Only a few hairs were examined.

CONCLUSIONS

The present results suggest that the microcanaliculi of the hair surface, easily found with scanning electron microscopy, may be secondary not only to the cavities seen in the sections but also to the disorder of proteins that form this region, demonstrated by the changes of the cortex dark lines.

Genetic Hair Disorders: A Review

Hair loss in early childhood represents a broad differential diagnosis which can be a diagnostic and therapeutic challenge for a physician. It is important to consider the diagnosis of a genetic hair disorder. Genetic hair disorders are a large group of inherited disorders, many of which are rare. Genetic hair abnormalities in children can be an isolated phenomenon or part of genetic syndromes. Hair changes may be a significant finding or even the initial presentation of a syndrome giving a clue to the diagnosis, such as Netherton syndrome and trichothiodystrophy. Detailed history including family history and physical examination of hair and other ectodermal structures such as nails, sweat glands, and sebaceous glands with the use of dermoscopic devices and biopsy all provide important clues to establish the correct diagnosis. Understanding the pathophysiology of genetic hair defects will allow for better comprehension of their treatment and prognosis. For example, in patients with an isolated hair defect, the main problem is aesthetic. In contrast, when the hair defect is associated with a syndrome, the prognosis will depend mainly on the associated condition. Treatment of many genetic hair disorders is focused on treating the primary cause and minimizing trauma to the hair.

Pili Annulati with Severe Trichorrhexis Nodosa: A Case Report and Review of the Literature

Pili annulati is generally classified as a hair shaft disorder without fragility. However, increased susceptibility to weathering is common. Severe breakage due to trichorrhexis nodosa is uncommon. We report a case and review the literature on this topic.

Prognosis and Management of Congenital Hair Shaft Disorders without Fragility-Part II

Hair shaft disorders are characterized by congenital or acquired abnormalities of the hair shaft. The objective of this study was to review the literature regarding the prognosis and treatment options for hair shaft disorders. We used keywords in the search engines PubMed and Medline to identify all publications in English related to the prognosis and management of hair shaft disorders. Data were extracted from 96 articles that met search criteria. Findings were limited to case reports and small case series, as no studies were found. Disorders that improve in childhood include pili torti, trichorrhexis invaginata, woolly hair, and pili trianguli et canaliculi. Others, such as trichorrhexis nodosa, monilethrix, pili annulati, and pili bifurcati, improve with minoxidil. Oral retinoids have been found to improve hair abnormalities in trichorrhexis invaginata and monilethrix. There is no specific treatment for congenital hair shaft abnormalities. Gentle hair care is the mainstay of care for hair shaft disorders associated with fragility. Practices for gentle care include no brushing, backcombing, chemical products, tight braids, heat exposure, or mechanical grooming. Furthermore, any inherited or congenital disorder requires genetic counseling as part of management.

Pili Annulati and Trichorrhexis Nodosa in the Same Patient: Cause or Coincidence?

PURPOSE

To determine the relationship between pili annulati (PA) and acquired trichorrhexis nodosa (TN) seen in the same patient, considering the two main theories evoked by previous studies: greater stiffness of darker PA bands or associated cuticular damage.

PROCEDURES

Light microscopy of hair shafts from different regions of the patient's scalp.

RESULTS

TN was not superimposed to dark bands of PA.

CONCLUSIONS

Greater stiffness of darker PA bands was excluded as the cause of hair breakage. Hair breakage in PA patients might be related to cuticular abnormalities, as previously reported. Because weathering of long thin chemically treated hairs is extremely common, coincidence cannot be completely ruled out in this case.

Hair morphology in androgenetic alopecia: sonographic and electron microscopic studies

OBJECTIVES

To assess hair morphology in androgenetic alopecia on sonography and electron microscopy.

METHODS

A prospective study was performed in 33 patients with androgenetic alopecia and 10 unaffected control participants. In vivo sonography of the hair follicles of the scalp and in vitro sonography and electron microscopy of the hair shafts were performed according to a standardized protocol that included analysis of the right frontal and occipital regions. The upper frequency limit of the ultrasound probes ranged between 15 and 18 MHz.

RESULTS

Scalp hair follicles and hair shafts were recognizable on sonography in all cases. Hair follicles in alopecia cases had significantly lower depths (P < .05). The hair shafts in alopecia also had a different distribution of their laminar pattern on in vitro sonography, with a greater presence of mixed (trilaminar and bilaminar) and solely bilaminar tracts in comparison with the controls (mostly trilaminar). On electron microscopy, the alopecia hair tracts showed irregularities and commonly a "melted candle" appearance of the cuticle.

CONCLUSIONS

Sonography and electron microscopy uncover distinct abnormalities in the morphology of hair in androgenetic alopecia, which may potentially support the diagnosis and management of this common condition.