Onychoscopy: an observational study in 237 patients from the Kashmir Valley of North India

Background Nail disorders comprise approximately 10% of all dermatological conditions. Because diagnosis is not always possible by clinical means alone, additional diagnostic procedures may be required at times. Dermoscopy of nails (onychoscopy) has shown promising results in diagnosing various nail disorders and also avoids time-consuming investigations such as culture and biopsy. Objective To study the dermoscopic features of various nail disorders to determine the correlation between KOH examination and onychoscopic patterns in patients with the clinical suspicion of onychomycosis, and to differentiate benign pigmented lesions from malignant ones. Methods An open, observational and cross-sectional study of 237 patients was conducted. All patients underwent clinical examination and the affected nails were examined with a dermatoscope. The onychoscopic patterns were identified and recorded. Results The study included 237 patients with the following diagnoses: 81 onychomycosis, 63 psoriasis, 27 lichen planus, 30 longitudinal melanonychia, 24 connective tissue disorders, 5 onychophagia and nail tics, 3 subungual verrucae, 2 glomus tumor, 1 Darier disease, and 1 enchondroma. The most common onychoscopic findings were spiked pattern in cases of onychomycosis, dilated and tortuous capillaries in cases of psoriasis, longitudinal streaks and nail fragmentation in cases of lichen planus, and enlarged capillaries in cases of connective tissue diseases. Limitations The study was only observational and did not compare the results to biopsy and culture. Conclusions Onychoscopy may be used as an important diagnostic tool when evaluating nail disorders. It should be used to aid in the diagnosis of various nail disorders and to avoid unnecessary and time-consuming investigations.


Introduction
Nail disorders constitute approximately 10% of all dermatological conditions, and the diagnosis is still a challenge [1].
Keeping in mind the various clinical difficulties in diagnosing nail disorders, and since some dermoscopic patterns are observed consistently with certain diseases, this study was conducted to evaluate various nail changes by using a dermatoscope.
A dermatoscope is a noninvasive diagnostic tool that visualizes subtle clinical patterns of skin lesions, hair disorders, and various nail changes not normally visible to the unaided eye [2].
In addition to diagnosis of common nail disorders, dermoscopy of nails (onychoscopy) provides useful information in the differential diagnosis of longitudinal melanonychia [3][4][5].The evaluation of longitudinal melanonychia should include personal and family history, clinical examination, and dermoscopic examination. All these together aid in making the differential diagnosis of the nail pigmentation and also help render a decision of whether to biopsy, where to biopsy, and how to biopsy [5,6]. Irregularities in the thickness, parallelism, spacing, and color of the brown-black bands are strongly suggestive of malignant melanoma. These patterns are highly specific and sensitive and may help in the diagnosis, selection of the type of surgery, and management [7].
We studied the dermoscopic features of various nail disorders to determine the correlation between KOH examination and onychoscopic patterns in patients with clinical diagnosis of onychomycosis and to differentiate various benign and malignant pigmented lesions.

Materials and Methods
This cross-sectional observational study was conducted in the dermatology outpatient department of a tertiary care hospital. Patients who either presented with nail disorders per se or were having nail involvement associated with various dermatoses were recruited for onychoscopic evaluation over a period of 1 year, from February 2016 through January 2017.
Relevant laboratory investigations such as KOH, culture of nail clippings, and nail biopsy were also carried out in selected patients wherever there was diagnostic difficulty. Patients of all age groups who consented to participate were included in the study; there were no exclusion criteria as such. All patients were subjected to clinical examination and dermoscopic examination. In all cases the affected nails were examined by a handheld dermatoscope (DermliteDL3N; 3 Gen, Inc, San Juan Capistrano, CA), with a magnification of 10×. Higher magnification of upto 30× was used wherever deemed necessary. Images were recorded directly by the digital camera of the dermatoscope with an attachment for iPhone 6. Both  Longitudinal melanonychia was seen in 30 (13.33%) patients. Fifteen patients had involvement of a single nail of great toe or thumb, only 6 had involvement of both great toes and thumbs, and 3 had involvement of multiple nails.
All patients were subjected to a proper history-taking and  In SLE, we observed capillary dilatations, hemorrhages, telangiectasias, enlarged tortuous capillaries, and normal density. In dermatomyositis, enlarged ramified/bushy capillaries, capillary loss, twisted capillaries, and hemorrhages were seen ( We found 2 patients with subungual bluish nodules, tender to touch. USG Doppler confirmed the diagnosis of glomus tumor after onychoscopy was done ( Figure 13).

Discussion
The use of dermoscopy in nail disorders is quite recent. Initially its use was limited to nail pigmentations, but nowadays it is frequently being utilized for the diagnosis of other nail disorders as well. In our study, the most common nail disorder observed was onychomycosis and the commonest pattern was distal and lateral subungual onychomycosis. Onychomycosis forms the most common nail disorder and accounts for nearly 50% of all onychopathies [8].
Since the treatment of onychomycosis can be long-standing and the morphology of the nail changes can vary, diagnosis cannot rely on clinical examination only. Therefore, we use KOH examination followed by culture of the samples [9,10].
Because culture is a time-consuming process and to decrease the number of samples to be sent for culture, we can utilize a dermatoscope, which is a noninvasive procedure that can aid in the diagnosis of onychomycosis.
Piraccini et al [11] retrospectively analyzed 57 digital dermoscopic images with clinical diagnosis of onycholysis; they identified and described specific dermoscopic signs for onychomycosis. Dermoscopic findings described for ony-   nonychia, and atrophy; nail bed involvement shows subungual hyperkeratosis, chromonychia, and onycholysis [16,17]. Another nail change that can be of concern in most patients is longitudinal melanonychia. This may represent a benign melanocytic nevus, lentigo, racial/ethnic mela-chomycosis were jagged proximal edge with spikes of the onycholytic area and longitudinal striae [11]. Nakamura et al [8] performed dermoscopy in 500 cases of nail disorders, and in onychomycosis they identified chromonychia, onycholysis, opacity, and longitudinal stripes.
In our study, the dermoscopic findings observed in onychomycosis showed jagged pattern of the proximal margin of the onycholytic area, spikes that were directed to the proximal fold, white-yellow longitudinal striae in the onycholytic nail plate (aurora borealis pattern), and distal irregular termination pattern.
The next common onychopathy in our study was nail psoriasis. Psoriasis can involve any structure of the nail apparatus, and accordingly there are different clinical manifestations [12]. So far the dermoscopic findings that have been observed in nail psoriasis include pitting, onycholysis, salmon spot, dilated blood vessels, splinter hemorrhages, dilated and tortuous capillaries in the hyponychium, and subungual hyperkeratosis [13,14]. Fine pits could be appreciated well with a dermatoscope [15].
We divided the nail unit changes in our patients into nail matrix and nail bed changes.      are more often seen in malignant melanoma [20]. In this study we observed blood spots and regular lines in patients with benign cause and irregular lines and micro-Hutchinson sign in patients with malignant melanoma.
Proximal nail fold changes are also common in con-

Conclusions
Onychoscopy is an easier, noninvasive, and cost-effective diagnostic tool that can allow detection of subtle nail changes not visible to the unaided eye. It can aid in diagnosing nail disorders earlier so that we can treat them before the disease progresses. In addition, it can help in differentiating benign lesions from malignant ones and accordingly guide us to