Onycholysis

Onycholysis refers to the detachment of the nail from the nail bed, usually starting at the tip and/or sides. On the hands, it is said to occur particularly on the ring finger but can occur on any of the fingernails. It may also happen to toenails.
Onycholysis can occur in many conditions, including psoriasis. In thyrotoxicosis it is thought to be due to sympathetic overactivity. It may also be seen in infections or trauma.