Nails: a window to systemic diseases

Abnormal changes in nails can be due to diseases primarily affecting nails and some of these nail changes can be a presenting feature before other signs of a systemic disease become clinically evident. The purpose of this review is not to address localized trauma or nail infections but offers examples of nail abnormalities that may occur with systemic disease. This paper includes information on common nail changes like koilonychia, longitudinal and transverse grooves, nail pitting, clubbing, nicotine-stained nails, cyanosis, and jaundice, information on the -nychias (leuko-, pachy-, melano- and dyschromo-), onycholysis and onychoschizia, yellow nail syndrome, Terry’s nails etc.