Onychoschizia, commonly known as nail peeling or nail splitting, is a condition that causes horizontal splits (across the width of the nail) in the nail plate. Onychoschizia may be seen along with another common nail condition called onychorrhexis, which involves longitudinal (across the length of the nail) splits or ridges in the nail plate. These conditions alone or together are sometimes simply called “brittle nails.”
Frequent wetting and drying of the hands is the most common cause of brittle nails. Brittle nails may also be caused by nail cosmetics (hardeners, polish, polish removers / solvents), nail procedures, and occupational exposure to various chemicals (alkalis, acids, cement, solvents, thioglycolates, salt, sugar solutions). Nail injury may also cause the development of brittle nails.
Brittle nails may also occur due to underlying medical problems such as gland (endocrine system) diseases, tuberculosis, Sjögren syndrome, and malnutrition. People with other skin diseases, such as lichen planus and psoriasis, as well as people taking oral medications made from vitamin A (retinoids), may also develop brittle nails.
