Onychoschizia, often simply referred to as brittle nail syndrome, is a common condition where the nail plate becomes fragile and prone to breakage. This fragility typically manifests as the horizontal splitting or peeling of the nail’s outermost layers, usually near the free edge. The nail plate is composed of multiple layers of keratin, and when the bonds between these layers are compromised, the structure loses its integrity. Understanding the difference between external damage and internal health issues is the first step toward restoring nail strength.
Mechanical Stress and Environmental Causes
The most frequent cause of nail splitting involves the cycle of hydration and dehydration, which compromises the external cohesion of the nail plate. Frequent exposure to water causes the keratin layers to absorb moisture, swell, and become temporarily soft. When the nail dries, the layers contract, and this constant swelling and shrinking weakens the intercellular adhesion between the keratin sheets, leading to peeling and splitting.
Harsh chemicals exacerbate this damage by stripping the nail of its natural oils and moisture. Substances like strong detergents, cleaning solvents, or acetone-based nail polish removers act as powerful dehydrating agents. Acetone, in particular, dissolves the lipid matrix that holds the keratin cells together, making the nail extremely dry, brittle, and susceptible to splitting.
Physical trauma, even seemingly minor, also contributes significantly to splitting. Using fingernails as tools to scrape, pry, or open objects can create micro-fractures in the nail structure. Even improper filing techniques, such as sawing the file back and forth, can create tiny tears at the nail edge that eventually propagate into full splits.
Underlying Health and Nutritional Factors
Internal systemic factors affect the nail matrix, the area beneath the cuticle where the nail is formed, leading to defects in the nail’s composition. Iron deficiency, with or without anemia, is a recognized contributor to brittle nails because iron is necessary for proper oxygen transport. Insufficient oxygen supply to the nail matrix can disrupt the synthesis of keratin, resulting in a thin, weak, and brittle nail plate.
In severe cases of iron deficiency, a unique nail deformity called koilonychia, or spoon nails, can develop. Hormonal imbalances, specifically an underactive thyroid gland, or hypothyroidism, also slow down the body’s metabolism. This reduced metabolic rate can decrease blood flow and nutrient delivery to the nail matrix, leading to slow-growing, dry, and brittle nails that split easily.
Aging is another non-controllable factor, as nails naturally become drier and more prone to splitting in older individuals. The water and lipid content of the nail plate decreases over time, making the keratin structure less flexible. Certain medications and other systemic conditions, such as psoriasis or eczema, can also interfere with normal nail growth and structure, resulting in fragility.
Practical Strategies for Strengthening Nails
Strengthening measures focus on both protecting the nail from external assault and improving its hydration and inherent quality. Protecting the nails from prolonged exposure to water and chemicals is paramount, which involves consistently wearing cotton-lined rubber gloves for wet work like dishwashing or cleaning. Switching from acetone-based polish removers to non-acetone formulations significantly reduces the drying effect on the nail plate.
Applying a moisturizing product directly to the nails and surrounding skin helps to restore the lipid barrier and maintain flexibility. Emollients like petroleum jelly or thick hand creams should be massaged into the nails, especially after any exposure to water. Regular application of a cuticle oil, rich in nourishing lipids, can help hydrate the nail plate and the matrix beneath the cuticle.
Proper Filing Technique
The technique used for shaping the nails also plays a large role in preventing splits. Nails should be filed in one single direction, moving from the side toward the center, rather than using a back-and-forth sawing motion. This sawing motion creates microscopic tears and frays the edge. Using a finer-grit file, typically 240 grit or higher, is gentler and creates a smoother, more durable edge that is less likely to catch and split.
Dietary adjustments can support nail health from the inside, emphasizing a balanced intake of protein, iron, and B vitamins. While biotin supplements are often marketed for nail strength, they are generally only beneficial if a true deficiency in the nutrient exists. For most people, focusing on whole foods that provide adequate vitamins and minerals is the most effective nutritional strategy.
Signs That Require Medical Attention
While most nail splitting is a cosmetic issue related to environmental factors, certain changes may signal a more serious underlying medical condition. It is advisable to consult a healthcare provider if the splitting is sudden, severe, or affects nearly all fingernails and toenails without a clear external cause.
Signs that require professional attention include:
- Increasing pain, swelling, warmth, or redness around the nail fold, suggesting infection.
- Discoloration, including yellow, green, or black spots beneath the nail plate.
- Splitting that occurs alongside systemic symptoms like unexplained fatigue, weight changes, or hair loss.
- Symptoms that may point to an undiagnosed thyroid problem or nutritional deficiency.