Drug-induced nail abnormalities.

A large number of drugs may be responsible for the development of nail changes, including cancer chemotherapeutic agents and retinoids, however, only a few classes of drugs are consistently associated with nail symptoms. Drug-induced nail abnormalities result from toxicity to the matrix, the nail bed, the periungual tissues or the digit blood vessels. The most common symptoms include Beau's lines, onychomadesis, melanonychia, onycholysis and periungual pyogenic granulomas. Drug-induced nail changes usually involve several or all of the nails. In most cases, nail abnormalities are asymptomatic, but can sometimes cause pain and impair manual activities.