Irritation of interdigital nerves (in the balls of the feet) may cause enlargement of the nerves, causing pain in the balls of the feet.
- Typical symptoms include a mild ache around the third or fourth toe that progresses to a burning or tingling sensation.
- The diagnosis is based on the person’s history and an examination of the foot.
- Injecting a corticosteroid or sometimes applying extreme cold (cryotherapy) can help relieve symptoms.
(See also Overview of Foot Problems.)
Damage to the nerves in the foot is a common cause of pain in the ball of the foot (metatarsalgia).
Causes of Damage to the Nerves in the Foot
The nerves that supply the bottom of the foot and toes (interdigital nerves) travel between the bones of the toes. Pain in the ball of the foot may be caused by longstanding irritation of the nerves. The irritation often causes the nerves to enlarge and noncancerous (benign) growths of nerve tissue (neuromas) to form, usually between the base of the third and fourth toes (Morton neuroma). However, these growths may occur between any of the toes. Neuromas usually develop in only one foot and are more common among women. Many factors contribute to nerve irritation, particularly nonsupportive or poorly fitting shoes. Other factors include thinning of the fat around the nerves, poor foot posture, or abnormal foot structure that stretches the nerves.
Symptoms of Damage to the Nerves in the Foot
In the early stages, a neuroma may cause only a mild ache around the third or fourth toe, occasionally accompanied by a burning or tingling sensation in the toes, particularly as the disorder progresses. These symptoms are generally more pronounced when a person wears certain types of shoes, especially those that are too narrow for the front part of the foot, including those that are pointed. As the condition progresses, a constant burning sensation may radiate to the tips of the toes, regardless of what shoes are worn. In time, most people are unable to wear most closed-toe shoes. A person may also feel as if a marble or pebble is inside the ball of the foot.
Diagnosis of Damage to the Nerves in the Foot
- A doctor's examination of the foot
Doctors diagnose damage to the nerves of the foot by considering the history of the problem and examining the foot.
X-rays, magnetic resonance imaging (MRI), and ultrasonography cannot accurately identify this disorder but may be helpful in ruling out other disorders that can cause similar symptoms.
Treatment of Damage to the Nerves in the Foot
- Footwear changes
Injecting the tender spot in the foot with a corticosteroid/anesthetic mixture and wearing proper shoes and sometimes orthoses (devices placed in the shoe) may relieve the symptoms. Rest and applying ice may also be recommended. Repeating the injections at intervals of 1 or 2 weeks may be necessary.
Sometimes cryotherapy (application of cold) or injection of alcohol into the neuroma may also relieve pain. If these treatments do not help, surgical removal of the neuroma often relieves the discomfort completely but may cause permanent numbness in the area.