Drug-induced nail diseases.

Although many nail disorders have been associated with drug intake, most reports are anecdotal. Most nail changes caused by drugs are the outcome of acute toxicity to the nail epithelia; nail symptoms depend on which nail structure is damaged. The most com-mon symptoms include Beau's lines/onychomadesis, melanonychia, onycholysis, and periungual pyogenic granulomas. Drug-induced nail abnormalities are usually transitory and disappear with drug withdrawal, but sometimes persist over time. This article reviews drugs that have been consistently associated with nail abnormalities.