The role of dermoscopy in the diagnosis of distal lateral subungual onychomycosis

Abstract

Recently dermoscopic patterns, that can be useful in the diagnosis of distal and lateral subungual onychomycosis, were identified. In this study, we aimed to determine the frequency of the defined patterns so far and additionally to identify other patterns that were observed and to investigate the place of these patterns in the diagnosis of Distal Lateral Subungual Onychomycosis (DLSO) in the dermoscopic examination of the patients with pre-diagnosis of DLSO. Patients admitted dermatology outpatient clinic of Haydarpasa Numune Training and Research Hospital with the complaint of nail disturbance suspicious for DLSO (97 patients) between the August 2015 and February 2016. Clinical and dermoscopic photographs of the cases with a pre-diagnosis of DLSO were taken and their nails were cut for pathological examination and culture. In hematoxylin and eosin, and periodic acid schiff examination, hyphe and/or spore were observed in 134 (65.4%) and fungal growth was detected in 99 (48.3%) of the nail samples. As a result of logistic regression model analysis, the p values of the 'ruin appearance', 'homogeneous leukonychia', 'punctate leukonychia', and 'black discoloration' patterns preserved their statistical significance (p = 0.015, p = 0.009, p = 0.026, p = 0.040, respectively). We believe that in nail disorders clinically resembling DLSO patients, the presence of dermoscopic patterns of ruin appearance, homogenous leuconychia, punctate leuconychia, and black discoloration strongly supports the clinical diagnosis of DLSO.

Onychoscopy: a quick and effective tool for diagnosing onychomycosis in a resource-poor setting

“…The onychoscopic feature of jagged edges with spikes is defined as jagged edges with spikes of the whitish longitudinal lines, seen on the proximal side of the onycholytic area and extending proximally in the nail plate (13). In this study, jagged edges with spikes were seen in 65.5% of the total cases.…”

“…Distal irregular termination or a "ruin appearance" refers to the end of the thickened nail plate ending with an irregular and crumbly appearance (13). In this study, distal irregular termination was seen in 82.7% of cases.…”

Nail Digital Dermoscopy in Onychomycosis: Correlation With Clinical Type, Gender And Culture Examination

“…Kaynak et al diagnosed 205 patients with DLSO and found that longitudinal striae pattern is observed in 79.5% of the samples, and that jagged edge with spikes pattern is observed in 63.4% of the samples. At the end of the study, they suggested that ruin appearance and punctate leukonychia are identified as dermoscopic patterns with high sensitivity only for DLSO diagnosis (11). In another study by Nargis et al, longitudinal striae and jagged proximal edges were seen in all patients, intermittent spiked pattern was seen in 78.3% of patients, and chromonychia and distal irregular termination were noticed in 38.3% and 11.7% patients, respectively (15).…”

“…The second most common pattern was ruin appearance, meaning subungual hyperkeratosis (54.0%) ( Fig. 2) (11). The incidence and distribution of other patterns are shown in Table 2 ( Fig.…”

“…In addition, they described a pattern as distal irregular termination in TDO and DLSO samples (13). It means "the end of the thickened nail plate ending with an irregular and crumbly appearance" (11). Its frequency was found in 20% of patients with OM, and it was more common in DLSO type (17.5%) and culture-negative samples (33.3%).…”