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Foot Pain Etiology: An Overview

Manouchehr Saljoughian, PharmD, PhD
Department of Pharmacy

Alta Bates Medical Center

Berkeley, California


6/19/2014

US Pharm. 2014;39(6):HS12-HS16.

One of the most complex parts of the human body and consisting of 26 bones that form two crossing arches, the foot is the platform of body movement. Foot pain signals a problem with the interaction of internal structures in the foot or the interaction between the foot and external objects. Where, when, and how the pain occurs are the primary clues to what is causing the pain. The body changes its movements or functions in an effort to reduce foot pain. Foot problems can cause pain, inflammation, or injury, resulting in limited mobility.1

Many people experience foot pain and discomfort. Foot pain may be due to aging, standing for long periods, being overweight, foot deformities, injuries, improper shoes, or too much walking, running, biking, and so on.1,2

This article presents an overview of foot pain and underlying causes, symptoms, and guidelines for prevention and treatment. In general, there are several ways to deal with foot problems, including home remedies, shoe inserts, physical therapy, medication, and surgery. Consultation with a podiatrist or other medical professional may be necessary for evaluation and treatment of foot problems.

Underlying Causes of Foot Pain

Arthritis: Arthritis presents in many different ways. Normally, it involves a breakdown of cartilage, which protects the joint so that it moves smoothly and absorbs shock when pressure is placed on the joint during walking and other activities. If there is insufficient cartilage, the bones rub together, resulting in pain, inflammation, and stiffness. Autoimmune diseases, wear and tear, and infection are some causes of arthritis.1,3

Joint inflammation subsides once the cause of inflammation disappears or is treated. In chronic arthritis, the inflammation remains, with osteoarthritis a possible cause. Joint pain and swelling result in reduced joint mobility, stiffness (especially in the morning), and warmth. Gout, a type of arthritis, occurs when uric acid builds up in the blood and causes inflammation, often in the joint of the big toe.1,3

Bunions: A bunion, or hallux valgus (hallux, big toe; valgus, abnormal angulation of the big toe), is a protrusion of bone or tissue around a joint. This condition, which is more common in women, sometimes runs in families. Wearing narrow-toed or high-heeled shoes may lead to the development of a bunion. The bunion may become painful as the bump enlarges, and extra bone and a fluid-filled sac form at the base of the big toe. The symptoms are red and callused skin along the inside edge of the big toe, a bony bump at the site, pain over the joint, and deviation of the big toe toward the other toes.4

A person can keep the bunion under control by making lifestyle changes when it first develops, including wearing properly fitting shoes. If the bunion worsens and becomes more painful, surgery to realign the toe and remove the bony bump can be effective. There are more than 100 different surgical procedures to treat this condition. Surgery reduces the pain in many cases, but not always. After surgery, people often have trouble wearing tight or fashionable shoes.4

Morton’s Neuroma (MN): This condition, which is more common in women, involves a buildup of bunion tissue in the nerves running between the long bones of the foot. The exact cause of MN is unknown; however, some experts believe that abnormal positioning of the toes, excess body weight, flat feet, bunions, hammer toes, tight or high-heeled shoes, and performance of high-impact activities may be involved in the development of this condition.4,5

The nerves of the toes pass under a strong band of ligaments that hold together the bones in the ball of the foot. MN most often develops between the third and fourth toes. Symptoms include tingling in the space between the affected toes, toe cramps, sharp or burning pain in the ball of the foot (and sometimes toes), pain that increases when shoes are worn, and lumps between the toes that feel like pebbles. Metatarsalgia (ball-of-foot pain), located on the foot behind the toes, may be caused by nerve or joint damage in that area, and frequently MN is responsible for the pain.4,5

Plantar Fasciitis: This condition (also called plantar fasciosis) is an inflammation of the thick band of tissues (plantar fascia) stretching across the bottom of the foot. The plantar fascia connects the heel bone to the toes and creates the arch of the foot ( FIGURE 1 ). Plantar fasciitis occurs when the plantar fascia is overstretched or overused. This causes heel pain and makes walking more difficult. The condition often affects people who run, jump, or stand for long periods of time. The pain is worst when the person first gets out of bed in the morning.6

Plantar fasciitis occurs in both men and women; however, it is more common in active men aged 40 to 70 years. Long-distance runners and people with arch problems, sudden weight gain, or a tight Achilles tendon are candidates for plantar fasciitis. The Achilles tendon, which connects the calf muscles to the heel bone, is the most common site of rupture or tendinitis from overuse.6

Plantar fasciitis is one of the most common orthopedic complaints. The following practices will improve the pain: heel- and foot-stretching exercises, night splints worn while sleeping to stretch the foot, resting as much as possible for at least a week, and wearing shoes with good support and cushioning. Treatment can last from several months to several years before symptoms improve, and nonsurgical treatments generally bring relief. Most patients feel better in 9 months; however, some people need surgery to relieve the pain.6

Hammer Toe: Hammer toe is a deformity in which the toe buckles, causing the middle joint of the affected toe to bend downward. Usually the second toe is affected, but the disorder can also occur in other toes. The most common cause of hammer toe is wearing narrow, too-small, or high-heeled shoes that are too tight. Hammer toe is more likely to affect women, but it also occurs in children who wear shoes they have outgrown. People should avoid wearing wrong-sized shoes, especially children during periods of fast growth, as the ligaments and tendons become tight and shorten.3,4

The condition may be congenital or develop over time. In rare cases, all of the toes are affected. This may be caused by a problem with the nerves or spinal cord. The end of the toe bends downward into a clawlike deformity; a corn often forms on the top of the toe, and a callus forms on the sole of the foot. Walking or wearing shoes can be painful.3,4

In severe cases, surgery may be required. The procedure often involves cutting or moving tendons and ligaments, and the bones on each side of the joints must be fused together. The toe may still be stiff afterward, and it may be shorter.3,4

Foot Ulceration: Foot problems in patients with diabetes account for more hospital admissions than any other long-term complications of diabetes. Foot ulceration is an important predisposing factor to amputation and is present in more than 80% of all diabetes-related amputations. Diabetic foot ulceration is considered to be a consequence of diabetic peripheral neuropathy and peripheral vascular disease. The cost of diabetic foot ulceration to the healthcare system is enormous, and pharmacists are in a unique position to reduce these costs by providing diabetes patients with counseling and preventive measures.4

Plantar Warts: Plantar (sole of foot) and palmar (palm of hand) warts are noncancerous skin growths caused by a viral infection, human papillomavirus (HPV), in the top layer of the skin. Many HPV strains exist, and those that cause common hand and foot warts are not the same strains that cause genital warts. Plantar and palmar warts are common, especially in children. Virtually everyone will develop one at some point.7

On average, plantar warts are about the size of a pencil eraser, but some grow bigger. Sometimes plantar warts grow in clusters, called mosaic warts. Plantar warts usually are less raised than warts on the hand, partly because of the pressure of walking and its flattening effect.7,8 Sometimes a corn or callus is mistaken for a plantar wart. Small black dots may appear in some warts, leading to the name seed wart. The black dots are actually tiny blood vessels that have grown up into the wart.7 Eventually (in about 2 years), most warts disappear without treatment. They can, however, cause irritation or minor pain, depending on their location.7

Flat Feet: In this common condition, a change in foot shape occurs when the foot does not have a normal arch when the person is standing. With flat feet, which are normal in infants and toddlers, the tendons holding together the joints of the foot are loose. The tendons tighten and form an arch, generally by age 2 to 3 years, and normal arches develop by adulthood. However, in some people, the arch never forms.8

Painful flat feet may develop in children when two or more foot bones fuse together, but flat feet that cause no pain or walking problems usually require no treatment. Aging, injury, or illness may harm the tendons and cause development of flat feet in a person who already has arches. This type of flat foot may occur only on one side.8

Stress Fractures: A stress fracture is a hairline crack in the bone that is caused by repeated or prolonged force against the bone. Stress fractures often occur from overuse, as in high-impact sports like distance running and basketball. Athletes participating in tennis, track and field, gymnastics, soccer, and basketball are at high risk for stress fractures. Most stress fractures occur in the weight-bearing bones of the foot and lower leg, especially when activity frequency, duration, and intensity are increased. When muscles are overtired, they transfer the stress to the bone, which can develop small cracks or fractures. People who do not exercise can also develop stress fractures. If osteoporosis or another disease has weakened the bones, normal daily activities may result in a stress fracture.4,5

The most common sites of stress fractures are the second and third metatarsal bones. Stress fractures also are common in the heel, the outer bone of the lower leg (fibula), and the navicular bone at the top of the midfoot. Rest is the key element to recovery from a stress fracture.4,5

Ankle Sprains: A sprain is an injury of the ligaments surrounding a joint. Ligaments are strong, flexible fibers that hold bones together. A sprain occurs when a joint, such as the ankle, is forced into an unnatural position. For example, twisting one’s ankle causes a sprain in the ligaments around the ankle. Joint or muscle pain, swelling, joint stiffness, and discoloration of the skin, especially bruising, are symptoms of a sprain.5

The following steps may lower the risk of ankle sprain: wearing protective footwear during activities that place stress on your ankle and other joints; making sure that shoes fit your feet properly; avoiding high-heeled shoes; always warming up and stretching before performing exercise or sports; and avoiding sports for which one has not trained.5

Broken Bones: If excessive pressure is put on any bone of the foot, it will split or break. Sometimes a broken bone punctures the skin (open fracture). Symptoms of a broken bone include out-of-place joints, swelling, bruising, bleeding, extreme pain, numbness and tingling, broken skin, limited mobility, and inability to move the limb.7

Causes of broken foot bones include falling from a height, motor vehicle accidents, direct contact with an object, and repetitive forces that can fracture the foot, ankle, or tibia (e.g., running). The end of the metatarsal of the big toe has two small, round bones; if broken, these bones may have to be surgically removed.7

Corns and Calluses: Corns and calluses are thick layers of skin that result from repeated pressure or friction in the same spot. A corn is thickened skin on the top or side of a toe; a callus is thickened skin on the hand or the sole of the foot.8 Foot calluses and corns are usually caused by poorly fitting shoes. The thickening of the skin is a protective reaction. For example, farmers and rowers get calluses on their hands that prevent blisters. People with bunions often develop a callus over the bunion where it rubs against the shoe. Corns and calluses are annoying and may be painful, but are not serious.8

Prevention and Treatment

Prevention: Various measures can be adopted to prevent foot problems and pain. Narrow-toed shoes and high heels should be avoided. Better choices are comfortable, roomy, properly fitting shoes with good arch support and plenty of cushioning around the toes and ball of the foot. Sneakers should be worn as often as possible, especially when walking, and running shoes should be replaced frequently.9

When exercising, it is important to warm up and cool down, and to increase the amount of exercise gradually to avoid excessive strain on the feet. Learning new exercises that strengthen the feet can prevent flat feet and other potential foot problems. Finally, weight loss, if needed, can help prevent foot problems.9

Home Care: A number of things can be done to relieve and treat foot pain. Using supportive devices and icing the foot will reduce pain and swelling, as will stretching and raising the painful foot as much as possible. Soaking the feet in a warm water and Epsom salt solution can relieve pain. Physical activity should be reduced, and shoes that fit and are suitable for the activity being performed should be worn. Foot pads may be worn to prevent rubbing and irritation. OTC pain medications, such as ibuprofen and acetaminophen, may be helpful.9

Medical Attention: A podiatrist will ask detailed questions about symptoms, the degree and location of pain, and the patient’s medical history in order to understand the nature of the foot pain and recommend medical treatment. X-rays may be performed to assist in diagnosis. Treatment may include a cast, if a bone is broken; removal of plantar warts, corns, or calluses by a foot specialist; orthotics; physical therapy and ultrasound to relieve tight or overused muscles; nonsteroidal anti-inflammatory medication; and foot surgery, especially for bunions, torn ligaments, and arthritis pain. Surgery often requires a long recovery period and is considered after other options have failed.9

REFERENCES

1. Goo J. Foot pain. www.medicinenet.com/foot_pain/article.htm. Accessed May 20, 2014.
2. Silverstein JA, Moeller JL, Hutchinson MR. Common issues in orthopedics. In: Rakel RE, Rakel DP, eds. Textbook of Family Medicine. 8th ed. Philadelphia, PA: Saunders; 2011:601-630.
3. Helfand AE. Primary considerations in managing the older patient with foot problems. In: Halter JB, Ouslander JG, Tinetti ME, et al, eds. Hazzard’s Geriatric Medicine and Gerontology. 6th ed. New York, NY: McGraw-Hill Professional; 2009:1479-1490.
4. Helfand AE. Foot problems: peripheral arterial, sensory, and diabetic problems. In: Capezuti EA, Siegler EL, Mezey MD, eds. Encyclopedia of Elder Care. 2nd ed. New York, NY: Springer Publishing Co; 2008:316.
5. Bryant JL, Beinlich NR. Foot care: focus on the elderly. Orthop Nurs. 1999;18:53-60.
6. Neufeld SK, Cerrato R. Plantar fasciitis: evaluation and treatment. J Am Acad Orthop Surg. 2008;16:338-346.
7. Anderson J, White KG, Kelechi TJ. Managing common foot problems in older adults. J Gerontol Nurs. 2010;36:9-14.
8. Robbins JM. Recognizing, treating, and preventing common foot problems. Cleve Clin J Med. 2000;67:45-47,51-52,55-56.
9. Porter RS, Kaplan JL, eds. Merck Manual of Diagnosis and Therapy. 19th ed. Whitehouse Station, NJ: Merck Sharp & Dohme Corp; 2011:3084-3088.

To comment on this article, contact rdavidson@uspharmacist.com.

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