A toenail falls off when something disrupts either the nail bed (the skin underneath) or the nail matrix (where new nail grows from the base). The cause is usually one of three things: physical trauma, a fungal infection, or an underlying health condition. In most cases, the nail will grow back on its own, though a full toenail replacement takes 12 to 18 months on average.
Trauma: The Most Common Cause
A single hard impact, like stubbing your toe or dropping something heavy on it, can cause bleeding beneath the nail. That pooling blood creates pressure between the nail plate and the nail bed, producing a dark discoloration and throbbing pain. If the blood pocket is large enough, it physically pushes the nail away from the bed, and over the following days or weeks the nail loosens and eventually detaches.
But you don’t need one dramatic injury. Repetitive, low-grade pressure does the same thing over time. Runners, hikers, and anyone who spends long hours on their feet in tight shoes can develop what’s sometimes called “runner’s toe.” Each stride jams the toenail against the front of the shoe, and after enough micro-hits, the nail separates. You might not even remember a specific moment of injury. Unrecognized microtrauma plays an important role in cases where people can’t pinpoint a cause.
Fungal Infections
Fungal nail infections start subtly: a white or yellowish spot at the tip of the nail, a slight thickening, some crumbling at the edges. Left untreated, the fungus works its way deeper, breaking down the bond between the nail plate and the bed beneath it. The nail becomes increasingly discolored, thick, and misshapen. Eventually the nail lifts off entirely.
Fungal infections are slow. They develop over months, not days, which is one way to distinguish them from trauma. The nail typically looks abnormal long before it starts to separate. If you also have diabetes, poor circulation, or a weakened immune system, fungal infections can progress faster and carry a higher risk of complications like secondary bacterial infection in the exposed nail bed.
Viral Illness and Nail Shedding
This one surprises people. Certain viral infections, especially hand, foot, and mouth disease, can cause nails to shed weeks after you’ve already recovered from the illness itself. The virus temporarily shuts down cell production in the nail matrix. Because nails grow slowly, you don’t see the damage right away. The nail loosens and falls off roughly four to six weeks after the initial illness. It’s a recognized late complication, not a sign that something else is wrong, and the nail almost always grows back normally.
Psoriasis and Autoimmune Conditions
Psoriasis doesn’t just affect skin. When it targets the nail bed, it causes a characteristic set of changes: salmon-colored “oil drop” spots visible through the nail, tiny splinter-like hemorrhages, a buildup of chalky material under the nail, and separation of the nail plate from the bed. The separation often starts at the tip and works backward. If you’ve noticed scaly patches on your skin, scalp, or elbows alongside nail changes, psoriasis is a strong possibility. Other autoimmune conditions can produce similar nail damage, though psoriasis is the most common culprit.
Medications That Affect Nail Growth
Chemotherapy drugs are particularly hard on nails because they target rapidly dividing cells, and the nail matrix is one of the most active growth centers in your body. The damage can range from horizontal grooves across the nail to complete separation and shedding. Certain targeted cancer therapies and seizure medications can do the same thing. If you’ve recently started a new medication and notice your nails loosening, the timing is worth mentioning to your prescribing doctor. The nails typically recover after treatment ends, though regrowth is slow.
How to Care for a Loosening Nail
If your toenail is partially detached, resist the urge to pull it off. A partially attached nail still protects the sensitive nail bed underneath. Keep the area clean, and cover it with a light bandage or adhesive dressing for padding. Over-the-counter pain relievers like ibuprofen or acetaminophen can help manage pain and swelling in the early days after an injury.
Trim the nail short so it doesn’t catch on socks or bedding. Avoid tight shoes. If the nail eventually comes off completely, keep the exposed nail bed covered and clean until the skin toughens. Watch for signs of infection: increasing redness, warmth, swelling around the nail fold, or any discharge. An untreated infection around the nail can, in rare cases, spread deeper into the toe and involve the underlying bone.
How Long Regrowth Takes
Toenails grow far more slowly than fingernails. A completely lost toenail takes up to 18 months to fully regrow, and after a significant injury or trauma, the timeline can stretch to two years. The new nail often looks slightly different at first: thinner, ridged, or a bit wavy. In most cases, it eventually returns to normal, though some people are left with a nail that’s permanently thicker or slightly misshapen if the matrix was damaged.
During regrowth, the nail is more vulnerable. Keep it trimmed, moisturize the surrounding skin, and wear shoes with enough room in the toe box so the new nail isn’t under constant pressure.
Preventing It From Happening Again
If trauma was the cause, footwear is the first thing to address. Get your feet properly sized at a shoe store, because foot size changes over time. Look for shoes with a roomy toe box that don’t squeeze or rub. If your foot slides inside the shoe, adjusting your lacing technique can lock the midfoot in place and keep your toes from jamming forward.
For fungal infections, keep your feet dry, change socks regularly, and wear breathable shoes. Treat any early signs of discoloration or thickening before the infection progresses to the point of nail loss. For conditions like psoriasis, treating the underlying disease is the most effective way to protect your nails long-term.