Onychoschizia comes from the combination of “Onycho” (nail) and “Schizia” (splitting, cracking).
It's the splitting of the nail into layers. The most common causes are excessive exposure to external factors such as water, detergents and acetone. Systemic conditions such as biotin, iron or thyroid deficiencies can also play a role. Excessive hard filing, cosmetic nail procedures or nail biting can also cause nail splitting.
What can be done?
Keeping nails moisturised (with urea or glycerine-based creams)
Wearing gloves for protection against chemicals
Choosing acetone-free nail polish remover
Vitamin supplementation (on a doctor's recommendation)
Handling nail care gently and carefully