Onychoschizia, commonly known as "nail splitting," is a condition that causes horizontal splits and cracks within the nail plate. When combined with vertical splits, the condition is known as "brittle nail syndrome." Nearly 20 percent of people have brittle nails, and the condition is seen most often in women and older people.
According to Skin Sight, you can identify cracked or splitting nails by looking for splitting and loosening nail layers at the nail tip. In splitting nails, the platelike nail layers separate. Splitting layers may appear as a single horizontal split or multiple splits. Splitting nails may also show vertical cracks on the nail, which can be long (from cuticle to nail tip) or short (for example, just at the nail tip). Nail splitting is generally considered a cosmetic problem, but can also cause some physical discomfort.
According to the Mayo Clinic, splitting nails are usually the result of the nails drying out, which can be caused by repetitive or prolonged contact with water or strong detergents (like frequent dish washing). Use of nail polish remover may also cause nail splitting. If your nails are yellow or white as well as cracking and splitting, you may have a fungal infection, according to WebMD. According to Skin Sight, people taking oral medications made from vitamin A may also develop nail splitting. Split and cracked nails may also be a sign of endocrine disorders, tuberculosis, Sjögren syndrome, malnutrition or skin conditions such as psoriasis or lichen planus.
To prevent split fingernails, avoid long baths, limit manicures, keep your fingernails trimmed, limit use of nail polish remover to twice a month (and use nonacetone remover), and rub moisturizing lotion or petroleum jelly on your fingernails after bathing or using nail polish remover. Wear gloves while doing housework or preparing food.
Protect splitting or cracking nails with several coats of nail lacquer. This will reinforce the nail. (Do not use artificial nails, as this can be detrimental to the nail plate.) Nail-hardening agents may increase nail strength, but should be applied to only the free edge of the nail as they can cause brittleness and other nail problems. Nail hardeners containing acrylate are also effective. Biotin supplements have also been found to benefit splitting nails.
If your nail splitting is caused by a fungal infection, you may need a prescription from your doctor, because anti-fungal creams often do not work. If your nail splitting is caused by psoriasis, your doctor may prescribe steroid creams, retinoid cream, or vitamin D cream. Ingested Vitamin D has no effect on this condition, according to WebMD.