Foot Conditions A-Z
Black toe is a relatively common condition among runners, vigorous walkers and participants in other sports where the feet are subjected to stress and strain, such as football, basketball, baseball and soccer. The condition generally is the result of impact trauma, especially in the big toe.
People who walk and run on hard surfaces such as concrete and asphalt are more likely to get black toe than those who exercise on natural surfaces or softer man-made surfaces. Hikers can experience black toe as a result of the toes banging against the front area of their shoes or boots, especially on downhill sections of trails.
The most common cause of black toe is repeated trauma from the toe banging against the end of the shoe. Since the big toe is usually the longest toe, the banging produces bleeding and bruising of the nail, causing it to become discolored (often blue and then black). The banging of the toe against the front of the shoe or boot is usually a sign that the shoes are too short, or that they fit too tightly and do not allow sufficient room for the feet to move dynamically during walking and running.
Other causes may include the following:
- sudden trauma or injury to the toe or toenail.
- fungal infection.
- “Morton’s toe,” a condition in which an individual’s second toe is longer than the big toe.
- Rarely, a subungual (occurring under the toenail) melanoma, a form of skin cancer.
Prevention and Treatment
Cut/trim your toenails to help avoid repeated trauma to the toes. Cut toenails straight across and soften sharp edges with an emery board or clean metal file.
IPFH suggests that you wear only properly selected and fitted, as part of an integrated approach, padded socks with shoes with non-slip outsoles and any inserts or orthotics prescribed or recommended by a doctor or foot health professional. Peer-reviewed, published studies have shown that wearing clinically-tested padded socks can help protect against injuries to the skin/soft tissue of the foot due to the effects of impact, pressure and shear forces. Padded socks also help protect the toes from the effects of impact inside the toe box of the shoe or boot, which is especially important for people who walk, run or hike in hilly or mountainous terrain.
Inserts or orthotics that provide extra cushioning are also beneficial. The insert or orthotic should not be slippery, since slippery inserts can cause the foot to slide forward. The result: the toe bangs even more than normal against the front of the shoe.
Properly designed and fitted shoes or boots have sufficient cushioning and room (about the width of a thumbnail) in the toe box so that excessive pressure is not exerted on the forefoot and the toes and toenails are not crowded too closely together.
Once black toe has occurred, it is usually best to simply leave the area alone; black toe generally disappears as the nail grows and the bruised area heals. In some cases, the nail may come loose and fall off. A new nail will take its place, but typically it takes about four to six months for it to grow to its full length.
If the black or discolored nail is the result of a fungal infection, an oral or systemic antifungal medication is often prescribed, instead of or in addition to a topical treatment.
If pain persists or swelling occurs, a doctor may need to relieve the pressure of the blood underneath the damaged nail or remove the nail altogether.
Severe discomfort in the toe and/or pus or redness that seems to be spreading can be signs of infection. See your doctor; left unattended, an infection can spread throughout the foot and into the bones.
People with diabetes or compromised circulation in the lower extremities should never try to treat toenail injuries (or any other foot issues) on their own, especially if there is any indication of possible infection or ulceration. See your doctor promptly.
If there are indications of subungual melanoma (length-wise discoloration usually limited to all or a portion of the big toe nail), see your doctor or a foot specialist immediately. Because of the possibility of subungual melanoma, many experts advise seeing a doctor or foot specialist for all cases of black toe, simply to rule out the condition.
Also talk to your doctor if you have soreness, pain, redness, swelling or other indications of foot problems that persist for more than a few days.