What are splitting nails?
Splitting nails, or onychoschizia, is a common problem in which thin layers peel from the free edge of the nail. The split runs horizontally through the nail plate rather than lengthwise.
Why does it happen?
Repeated cycles of wetting and drying are the main cause. Water softens and swells the nail; as it dries, the plate contracts. Frequent exposure to soap and detergents intensifies dehydration. Tiny separations then trap more water, dirt and cleanser, allowing further peeling. Repeated trauma to the tips also contributes. Less often, brittle splitting accompanies an underlying disorder such as polycythaemia vera, but most cases are related to exposure rather than internal disease.
Who is affected?
Onychoschizia is seen particularly often in women, partly because wet work and cosmetic nail practices may increase repeated stress. Fingernails are generally more exposed than toenails.
Treatment and prevention
Reduce prolonged contact with water, soap, detergents and food juices. Wear protective gloves for washing and food preparation, ideally keeping the inside dry. Apply a bland moisturising ointment to nails and surrounding skin after washing. Keep nails moderately short and file rough edges gently in one direction rather than pulling off layers. Nail lacquer may provide temporary reinforcement, either over the plate or just at the tips, but removers and repeated cosmetic procedures can worsen dryness.
When to see a doctor
Seek assessment when splitting begins suddenly, affects many nails severely, causes pain or inflammation, or occurs with colour change, thickening, pitting or other general symptoms. A clinician can distinguish repeated wet-work damage from fungal infection, psoriasis, iron-related problems or a rarer systemic cause.