Nails should be kept short. Also, in questioning some people with this problem I find they are mechanically cleaning under the nails farther and farther in an effort to keep the area clean. This continues to lift the nail away from the nail bed and worsens the problem. Mechanical cleaning with nail files and brushes should be questioned. Additionally, ultraviolet light plus certain meds, eg anti-inflamatories, can cause onycholysis.
Many cosmetologists wear artificaial nails.
Most conventional wisdom has it that onycholysis is due to trapped water under the distal nail plate which encourages the growth of yeast. The candida causes separation of the nail plate from the nail bed. Excelderm or lotrimin solution also work in many cases. Keeping the area dry is the most effective treatment in my experience. I've also had luck trimming the nail back as far as it will go and applying nizoral cream to the finger tip T.I.D. till the nail grows back.