A new toenail can grow under an old one; this is a common and predictable part of the healing process after severe damage or infection. Toenails are composed of keratin, forming the visible nail plate that rests on the nail bed. New nail growth begins at the nail matrix, the hidden root beneath the cuticle. This replacement process ensures the sensitive underlying tissue remains protected while a healthy nail plate regenerates.
How the New Nail Replaces the Old One
The mechanism for replacing a damaged nail begins in the nail matrix. This specialized tissue continuously produces new keratin cells, which form the new nail plate. If the matrix remains intact after an injury, it continues generating these new cells and pushing them forward along the nail bed.
As the new nail plate forms, this forward movement exerts upward pressure on the old, damaged nail. This pressure forces the old nail to detach from the nail bed. The old nail acts as a protective shield for the delicate nail bed underneath until the newly formed nail is strong enough to take its place. The old nail will eventually loosen and fall off completely as the new nail grows out.
The Time Required for Complete Regrowth
The duration required for a complete toenail replacement is significantly longer than for a fingernail. On average, a toenail can take 12 to 18 months to fully regrow after being lost or removed. The slower growth rate is believed to be due to reduced blood flow compared to the fingers, and the constant pressure and minor trauma from walking and footwear. Several individual factors also influence how quickly a toenail regenerates, including age, overall health, circulation, and the severity of the initial injury.
Proper Care During the Healing Phase
Protecting the toe is important during the long regrowth period, especially once the damaged nail has detached, leaving the nail bed exposed. The area must be kept clean and dry to prevent infection, often by gently washing it with mild soap and water daily. Applying a thin layer of petroleum jelly and covering the area with a non-stick sterile bandage can help protect the sensitive tissue from friction and dirt.
If the old, lifting nail is causing snagging or discomfort, it can be gently trimmed away, but only the part that is completely detached from the nail bed. Wearing shoes that are roomy and have a wide toe box is recommended to avoid repeated trauma to the recovering nail.
It is important to seek medical attention if signs of infection develop, such as increased redness, swelling, warmth, pus, or persistent severe pain. Consulting a professional is also advisable if the new nail grows in severely misshapen or thickened, which may indicate damage to the nail matrix.