Abstract
INTRODUCTION: Nail changes have been described in syphilis in all stages. However, they can be subtle and easy to miss. At the same time, they are valuable indicators towards underlying pathology as nail is a useful "window to systemic disease." Onychoscopic features of nail syphilis have not been described in detail. CASE REPORT: We describe 3 patients (n = 60 nails) with secondary syphilis with involvement of 29/60 (48.3%) nails. Most common clinical nail findings were onychorrhexis (13, 37%), followed by distal onycholysis (10, 28%). Other findings included subungual hyperkeratosis, onychomadesis, Beau's lines, nail plate atrophy, paronychia, and periungual ulceration. Onychoscopic involvement was seen in 32/60 (53.3%) nails. Features observed on onychoscopy were onychorrhexis (13/60) and distal onycholysis (including erosive onycholysis) (12/60). Distinctive features on onychoscopy included alternate white and red lines, longitudinal erythematous bands, and ulcerative onycholysis. CONCLUSION: Nail involvement in syphilis, particularly the onychoscopic findings, has been under-reported. Varying terminologies have been used over the years as per the literature review. We propose that nail syphilis is best classified based on the site of involvement within the nail unit. Onychoscopy aids the detection of changes which may be missed on clinical examination.