Original article
Hair abnormality in Netherton syndrome observed under polarized light microscopy

https://doi.org/10.1016/j.jaad.2019.08.024Get rights and content

Background

Trichorrhexis invaginata, the main diagnostic feature of Netherton syndrome, is often difficult to detect, especially in adult patients.

Objective

We sought to describe a characteristic feature of hairs in Netherton syndrome using a polarized light microscope and the underlying histopathologic changes.

Methods

Hairs obtained from 8 patients with Netherton syndrome were observed under polarized light, and we evaluated the correlation between number of band-like patterns and disease severity.

Results

Under polarized microscopy, the hair shafts of 8 patients showed a characteristic band-like pattern under polarized light that was not observed in healthy control individuals or patients with atopic dermatitis. This discontinuity of polarized light shows a band-like pattern in which the bands mostly ranged from 0.1 to 1.0 mm in width. The observed ratio of this finding was significantly higher than that of trichorrhexis invaginata observed under light microscopy, and patients with severe dermatitis tended to have a higher ratio than those with less severe dermatitis.

Limitations

Comparative examination among other congenital ichthyoses was not performed.

Conclusions

A band-like pattern in hairs with polarized light microscopy can be seen in Netherton syndrome and may have potential utility as a diagnostic marker.

Section snippets

Index case

A 34-year-old Japanese man (patient 1 in Table I) presented with ichthyotic erythema throughout the body, ichthyosis linearis circumflexa, and alopecia on the scalp. His hair could be easily pulled out from the scalp. He also exhibited short stature (143 cm, 41 kg) and a slight intellectual disability. His elder brother had also shown similar cutaneous manifestations. Although NS was strongly suspected, TI could not be observed despite repeated hair examinations. Therefore, trichothiodystrophy

Observation by light and polarized microscopy

We validated whether this characteristic hair feature observed under polarized microscopy in our index case is generally common to patients with NS. We analyzed hairs from 8 Japanese patients with NS, including 2 siblings (patients 1 and 2 in Table I). Clinical features and hair phenotypes evaluated by patients' attending doctors are summarized in Table I. The patients' hair showed mostly purple to dark green polarized light under microscopy; however, there were occasional gaps exhibiting

Discussion

In this study, we discovered the distinct feature of polarized light discontinuity in hairs of patients with NS. This feature was found in all the recruited patients with NS but in none of the healthy control individuals or patients with atopic dermatitis, suggesting that this polarized light feature is specific to patients with NS. TI often improves with age and can sometimes completely abate; therefore, it can be difficult to find in some NS cases.5, 6 It is interesting and clinically

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Funding sources: Supported by a Grant-in-Aid for Scientific Research to Dr Takahashi from the Ministry of Education, Culture, Sports, Science, and Technology of Japan.

Conflicts of interest: None disclosed.

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© 2019 by the American Academy of Dermatology, Inc.