Background: Nail disorders comprise approximately10% 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.

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.