What causes fingernails to split into layers?

　　Fingernail layering (onychoschizia) may be caused by aging, nutritional deficiencies, frequent manicures, onychomycosis (fungal nail infection), or nail psoriasis. Appropriate management can be selected based on specific circumstances. If discomfort occurs, timely medical consultation is recommended.

　　1. Aging: With advancing age, the growth rate of the nail plate slows down, and the texture of the fingernails may become fragile, making them prone to layering. Keeping the fingernails appropriately moisturized and regularly applying hand creams containing nourishing ingredients to the nails and nail edges can help reduce the occurrence of onychoschizia.

　　2. Nutritional deficiency: Long-term dietary imbalances and deficiencies in nutrients such as protein, vitamin A, calcium, and iron can affect normal nail growth and lead to fingernail layering. It is important to adjust the diet to ensure sufficient intake of meat, eggs, dairy products, and fresh fruits and vegetables. Nutritional supplements may be taken under medical guidance if necessary.

　　3. Frequent manicures: Tools and chemical agents used during manicures, such as nail polish and nail polish removers, can damage the surface of the fingernails and disrupt their structure, causing nail layering. Reduce the frequency of manicures to allow the nails sufficient time for self-repair. Regular application of hand cream can help nourish the skin around the nails.

　　4. Onychomycosis: Caused by fungal infection of the nail (e.g., dermatophytes), fungal proliferation within the nail destroys its structure, causing thickening, discoloration, layering, and an uneven surface. Patients may use medications such as itraconazole capsules, terbinafine hydrochloride tablets, or amorolfine topical solution under medical guidance to alleviate symptoms.

　　5. Nail psoriasis: Fingernail layering may also be related to psoriasis when the condition affects the nails. Characteristic manifestations include pitting resembling a thimble, onycholysis (separation of the nail), and layering. This may be accompanied by symptoms such as skin redness and scaling. Patients may use calcipotriol solution, tazarotene gel, methotrexate tablets, or other medications as directed by a physician to relieve symptoms.

　　In daily life, it is recommended to maintain a bland diet and avoid spicy or irritating foods such as garlic, hot pot, and mustard. Adequate rest and maintaining hand hygiene are also important.