Cronkhite-Canada syndrome (CCS) is a rare disorder characterised by gastrointestinal polyposis and ectodermal changes, represented by extensive alopecia. Detailed histopathological investigations of alopecic lesions in two female CCS patients with severe hair loss revealed a marked increase in telogen hair follicles with no sign of loss or of the minaturisation or atrophy of hair follicle structures and the absence of inflammatory change, despite severe inflammation in the gastrointestinal tract. These findings suggested that hair regrowth can be expected without systemic corticosteroids, if they are not necessary for treatment of the gastrointestinal tract, and that anagen-telogen transition is an early event preceding clinical hair loss in CCS.

Histopathological comparison between clinically affected and intact regions in alopecia patients has been considered to facilitate better understanding of the pathophysiology of ongoing disease. Theoretically, adjacent intact regions should provide ideal controls as they should share close histological characteristics, however, to what extent clinically non-affected neighboring regions maintain their pathological integrity has not been fully assessed. The goal of this study is to delineate histopathological characteristics of clinically intact perilesional regions in the patients with various forms of alopecia. Transverse sections of 4-mm punch biopsy at the levels of isthmus and suprabulbar portion were obtained from seemingly unimpaired perilesional scalp of 50 Japanese alopecia patients (16 alopecia areata [AA] multiplex, 19 scarring alopecia [SA], 15 other conditions) and subject to histopathological investigation. Initial screening detected decrease in anagen (anagen : telogen ratio = 82.4:17.6) when compared with previously reported standard hair counts in normal Asian scalp. This finding prompted further investigation. Unexpectedly, 33 (66%) specimens demonstrated some microscopic abnormalities, 10 (62.5%) AA specimens showed increase in telogen ratio, vellus hair count and miniaturization, while perifollicular inflammatory cell infiltration was detected in 5 (26.3%) SA cases. Exclusion of histologically affected specimens yielded average hair count numbers resembling those reported in Koreans, supporting the pathological integrity of selected samples and, more importantly, indicating normal hair counts in east Asians. These findings indicated a less recognized significance of histopathological investigation of clinically non-affected perilesional scalp in alopecias for better assessment of the spread of disease activities, which should enable better management of hair loss conditions.

Onychomycosis with longitudinal spikes in the nail plate has been reported to be refractory to oral drugs as with dermatophytoma. We evaluated the efficacy of 10% efinaconazole solution in the treatment of onychomycosis with longitudinal spikes. Of the 223 subjects who were enrolled in a previous study, a post‐hoc analysis of 82 subjects with longitudinal spikes was performed in this study. The opacity ratio of longitudinal spikes was decreased over time from 8.1 to 0.9 at the final assessment. In addition, the longitudinal spike disappearance rate increased early after the application to 81.7% at the final assessment. Therefore, 10% efinaconazole solution can be a first‐line drug for longitudinal spikes, which have been regarded as refractory to oral drugs.