Toenails, composed of a tough protein called keratin, serve as protective coverings for the sensitive tips of our toes. They shield underlying soft tissues and nerve endings from injury. A common question arises when a toenail is damaged: can a new toenail grow underneath an existing one?
How Toenails Grow Back
The process of toenail growth originates from the nail matrix, a specialized tissue located at the base of the nail, mostly hidden beneath the skin. This matrix continuously produces new cells. As these new cells form, they harden with keratin, flatten, and are pushed forward, creating the visible nail plate. The nail matrix is responsible for approximately 90% of nail growth, determining its thickness, width, and shape.
When a toenail is partially or completely lost due to trauma, infection, or other issues, the nail matrix, if undamaged, will typically begin producing new nail material. This regrowth process is continuous. Toenails generally grow slower than fingernails, with an average rate of about 1.5 to 2 millimeters per month. A complete toenail regrowth can take anywhere from 6 months to 2 years, depending on factors like the extent of the damage, age, and overall health.
Understanding New Nail Growth Underneath
When a new toenail appears to be growing “under” an existing one, it is usually a natural replacement process. This occurs when the old, damaged, or detached nail is still present on the nail bed. The new nail, originating from the nail matrix at the base, grows forward underneath the old nail. As the healthy new nail progresses, it physically pushes the old, non-viable nail plate upward and off the nail bed. This displacement ensures the damaged nail is shed, allowing the new nail to take its place.
This phenomenon is commonly observed after an injury, such as stubbing a toe or dropping an object on it, which can cause the nail to lift from its bed. Fungal infections can also lead to nail thickening, lifting, or discoloration, prompting the growth of a new nail underneath. The presence of the old nail, even if detached, can offer some temporary protection to the sensitive nail bed beneath while the new nail forms. While the new nail is growing and pushing off the old one, some individuals might experience discomfort due to pressure, especially when wearing closed-toe shoes.
Caring for a Damaged Toenail
Caring for a damaged or detaching toenail involves gentle care and hygiene. It is important to keep the area clean and dry to prevent infection. If the nail is partially detached, trimming away any sharp edges can prevent further snagging and injury. Applying an antibiotic ointment and covering the area with a non-stick bandage can protect the exposed nail bed, changing the bandage daily or whenever it becomes wet or dirty.
Avoid forcibly removing the old nail, as this can cause pain and increase the risk of infection. Elevating the foot and applying a cold compress can help reduce swelling and pain in the initial stages of injury. It is advisable to wear open-toed shoes or sandals if closed-toe footwear causes discomfort. Seek professional medical attention if there are signs of infection, such as increased pain, redness, swelling, pus, or a foul odor. A podiatrist can assess the damage, safely manage the old nail, and provide guidance to ensure healthy regrowth, especially if the new nail appears misshapen or if pain persists.