Foot pain may be caused by many different diseases, deformities, biomechanical conditions, improper footwear, or injuries.
Infectious disease, viruses, fungi, and bacteria can cause foot pain. Plantar warts on the bottom of the foot are caused by a virus and can cause irritation and discomfort. Athlete’s foot, which is caused by a fungus, can lead to foot irritation and pain. A common cause of foot pain is an ingrown toenail. Ingrown toenails occur when the edges of the nail grow through or into the skin, resulting in pain and often leading to infection. Patients with diabetes are more prone to infection since their immune system is compromised.
Many systemic diseases, such as diabetes, lupus, gout, and rheumatoid arthritis, can cause foot pain. Rheumatoid arthritis can cause painful inflammation in the joints of the foot, accompanied by alignment changes that lead to foot deformities.
Deformities, such as tarsal coalitions, calcaneal varus, calcaneal valgus, bunions, claw toes, mallet toes, hammertoes, and bone spurs, are common causes of foot pain.
Biomechanical abnormalities from muscle and tendon tightness or laxity, flat feet, or high arched feet often lead to muscle imbalances, deformities, and foot pain.
Trauma from an acute injury or accumulative repetitive injury is a prevalent cause of foot pain. An example of such damage is Achilles tendinitis or rupture. The tendon can rupture from an acute, sudden injury, or it can become inflamed (tendinitis) from repetitive insult to the structure. Small repetitive traumas or pressures may also cause damages to the skin and internal structures. Micro-trauma injuries can be caused by running on uneven surfaces or surfaces that are too hard or too soft, or wearing shoes that have poor force-absorption qualities, are not activity-specific or fit incorrectly.
Wearing shoes that are too tight or high heels can cause pain in the forefoot. Shoes that are tied too tightly can cause pain and bruise on the top of the foot. Improper, non-sport specific shoes for running or cycling can lead to foot pain with activities. Poorly fitting shoes in the short term can cause blisters, bruising, and be a source of athlete’s foot. The long-term effects of poorly fitting shoes may be bunions, corns, calluses, irritation of nerves and joints, and misalignment of the toes. Morton’s neuroma caused by thickening of tissue around a nerve between the toes can cause toe numbness and pain. It may also be aggravated by ill-fitting shoes, as can many foot deformities such as hammertoes, mallet toes, and bunions.
Injuries such as ligament sprains, muscle strains, bruises, and fractures typically occur suddenly (acutely). Sprains, strains, bruises, and fractures may be the result of a single or combination of stresses to the foot. An injury of the foot or ankle occurs when ligaments that hold the bones together are overstretched, and their fibers tear or stretch too far. The looseness of ligaments in the joints of the foot may lead to chronic foot pain, joint instability, and deformity. Repeated overstressing of the same foot structure may cause stress fractures, tendonitis, plantar fasciitis, and acute and chronic osteoarthritis. Stress fractures commonly occur in the metatarsal bones, the long bones of the foot, and can happen in the tarsal or rear-foot bones. These fractures are often called march fractures because it is usually caused by non-distinct and minor stress of excessive walking (marching) rather than a significant traumatic event.
The muscles and fascia of the foot can be strained by overstretching, overuse, or overloading. Achilles tendonitis is a common injury of the tendon that attaches at the back of the heel. Plantar fasciitis (the most common cause of heel pain) is a result of micro-trauma strain to the broad ligament called the plantar fascia. Tendon pain and swelling from repetitive abnormal strain lead to tendinitis, which can eventually lead to tears in the tendons.
Injury to the bones and joints of the foot can be caused by a single blow or twist to the foot or also by repetitive trauma that can result in a stress fracture. A blunt-force injury such as someone stepping on your foot may result in a bruise (contusion) injury and damage to the muscles and ligaments of the foot. Direct blows to the foot can cause bruising, breaking of the skin, or even fracturing of bones. Metatarsalgia is from the repetitive irritation of the joints of the ball of the foot. The term “stone bruise” is commonly referred to as a specific localized pain and tenderness of the ball of the foot. “Turf toe” is a common athletic injury in which the tendon and capsule under the joint at the base of the big toe is strained. Trauma to the toenail can cause pooling of blood under the nail and the temporary or permanent loss of a toenail. Repetitive injury to the bones, muscles, and ligaments can result in extra bone growth known as spurs or exostoses.
Delayed treatment of many foot pain can lead to complications, chronic long-term pain, disability, and arthritis of the affected foot.
