Summary
Ingrown toenails, medically termed onychocryptosis, occur when the corner or edge of a toenail grows into the surrounding skin of the big toe. Several distinct causes have been identified, ranging from nutritional deficiencies to mechanical and physical factors. Understanding the root cause is key to addressing and preventing the condition.
Key Takeaways
- Low calcium can cause toenails to grow soft and distorted, leading them to grow into the skin
- Low vitamin D is linked to ingrown toenails, likely through its role in calcium absorption and nail integrity
- Improper nail cutting technique is a common mechanical cause — nails should be cut straight across, not rounded at the edges
- Tight footwear that presses against the toenail can force it to grow inward
- Toenail injury from impact or trauma can alter nail growth direction, causing it to grow into surrounding tissue
- Multiple causes can be nutritional, mechanical, or physical in origin
Details
Nutritional Causes
Calcium deficiency and vitamin D deficiency are identified as potential nutritional contributors to ingrown toenails. Without adequate calcium, nails may become soft and lose their structural integrity, causing them to distort and grow abnormally into the surrounding skin rather than outward in a healthy direction.
Nail Cutting Technique
Incorrect trimming is a preventable mechanical cause. The recommended technique is to cut toenails straight across rather than rounding or curving the edges. Rounding the corners removes the natural barrier that keeps the nail growing outward, allowing the edges to dig into the adjacent skin tissue.
Footwear
Shoes that are too tight can apply direct pressure onto the toenail, physically pushing it into the surrounding skin over time. Proper-fitting footwear is important for nail health.
Physical Injury
Direct trauma to the toe — such as from dropping a heavy object, playing soccer, or kickboxing — can damage the nail bed and alter the direction of nail growth, causing it to grow inward into the tissue. Even a single injury event can have lasting effects on nail growth patterns.