Hair abnormality in Netherton syndrome observed under polarized light microscopy

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. Trichorrhexis invaginata, the main diagnostic feature of Netherton syndrome, is often difficult to detect, especially in adult patients. We sought to describe a characteristic feature of hairs in Netherton syndrome using a polarized light microscope and the underlying histopathologic changes. 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. 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. Comparative examination among other congenital ichthyoses was not performed. 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.