Common nail disorders.

Brittle nail, simple chronic paronychia, and onycholysis represent three of the most prevalent nail disorders. Brittle nails are characterized by increased fragility of the nail plate due to damage to the nail matrix or changes to nail plate cohesion, caused by internal and/or external factors. Simple chronic paronychia represents an inflammatory process of the lateral and/or proximal nail folds of the fingernails or toenails often preceded by damage to the cuticle. Onycholysis describes the detachment of the nail plate from its nail bed, often attributable to dermatologic conditions, infections, drug therapy, or trauma.