Pain can affect any part of the foot, including the ankle, heel, sole, arch and toes. Potential causes of foot pain include:

• Problems caused by pressure. The feet withstand enormous pressure while standing and walking. Pressure on the feet from ill-fitting shoes causes skin to rub and can shift the bones. This may result in numerous foot conditions, including:
  
• • Callus. Area of hard skin that forms on the foot from excess pressure.
    
    
  • Corn. Area of hard skin that forms on the toes.
    
    
  • Bunion. Occurs when compression forces the big toe joint to enlarge and turns the big toe toward the other toes. A painful, reddened area forms near the joint. Bunions can be caused by tight or high-heeled shoes that compress the toes.  Other foot problems, such as flat feet, may contribute to bunions. The tendency to develop bunions may appear to be inherited, although the structure of the foot (e.g., flat feet) is inherited, not the bunion.
    
    
  • Hammertoe. Occurs when compression forces the lesser toes to bend over in a claw shape, shortening their tendons. They are usually caused by shoes that compress the toes. Conditions that affect the muscles and nerves, such as diabetes and arthritis, may contribute to the development of hammertoe.
    
    
  • Metatarsalgia. Pain in the ball of the foot, which may be caused by bunions, hammertoes, poorly fitting shoes or high-impact athletics such as running.
    
    
• Plantar warts. These warts grow from a virus on the sole (plantar surface) of the foot. A wart on a finger will grow outward, but because of the pressure of standing, plantar warts grow inward. They become painful and may spread to form other warts.
  
  
• Trauma. The feet and ankles are susceptible to breaks or stress fractures of the bones, joint dislocations, and strains and tears of the ligaments and tendons. The most common tendon injury in the foot is to the Achilles tendon, which connects the calf muscle to the heel. Although most of the tendon is in the calf and ankle, the injury usually causes heel pain. Jumping, running or abrupt movements can strain, tear or even rupture the tendon.
  
  
  Common ankle injuries include stretching, partial tear (sprain) or complete tear to a talofibular ligament or calcaneofibular ligament. Ankle impingement syndrome involves acute trauma or chronic strain (e.g., stepping in a hole, playing sports) that causes bony or soft-tissue compression in the ankle.

• Arthritis. Arthritis is inflammation of the joints. Each foot has 33 joints and bears enormous weight, so it is quite susceptible to arthritis. Arthritis in the foot may cause pain, swelling, stiffness and limited range of motion. Of the many forms of arthritis, those that often involve foot pain include:
  
• • Osteoarthritis (OA). A gradual breakdown of cartilage in the joints. This is the most common form of arthritis, but it tends to affect the hands, knees, hips and spine more than the feet.
    
    
  • Gout. A type of arthritis where deposits of uric acid build up in joints. The metatarsal-phalangeal joint (big toe joint) is the most common site for gout attacks, which can cause acute pain, swelling and redness.
    
    
  • Rheumatoid arthritis (RA). A debilitating autoimmune disease that can deform bones and tendons. The foot joints are among the first affected by RA.
    
    
  • Reiter’s syndrome. A form of infectious arthritis that can involve heel spurs or other abnormal growths in bones of the feet.
    
    
  • Ankylosing spondylitis. A form of arthritis that often begins in the sacroiliac joints between the lower back and pelvis, and that can also affect the hips, knees, ankles and shoulders.
    
    
• Diabetes. People with diabetes may have long-term damage to their nervous and circulatory systems that affect the feet. Diabetic neuropathy is a type of nerve disease. When nerves in the legs and feet are damaged, a person may not feel pain or pressure. Consequently, patients may not notice an ulcer or problem that develops in their feet. These patients are thus more susceptible to injury due to numbness. Some types of neuropathy can also cause pain in the feet, characterized by tingling or burning sensations. Many diabetes patients with neuropathy have overly sensitive feet and even the slightest touch results in pain (allodynia).

Diabetes patients frequently have impaired circulation, such as peripheral arterial disease, particularly in their legs. Without good blood flow, a cut or infection in the foot heals more slowly. Diabetic foot ulcers can worsen and infect the foot and leg. Eventually, an untreated ulcer may require amputation of the foot. Diabetic patients with impaired sensation may also develop Charcot foot, in which minor trauma goes unnoticed, worsens and leads to deformity.

• Heel conditions. Pressure on the heel causes specific types of pain:
  
• • Plantar fasciitis. The plantar fascia is a connective tissue that runs along the bottom of the foot from the heel to the ball of the foot. When the fascia is overstretched, tiny tears may cause inflammation or degeneration over time. The condition causes pain in the heel and just in front of it, usually after getting out of bed or after standing for long periods of time. It is common in athletes and people with flat feet.
    
    
  • Heel spurs. Small outgrowths on the heel bone.
    
    
  • Haglund’s deformity. A painful bump on the back of the heel caused by shoes with rigid backs.
    
    
• Inflammation. The soft tissues and sacs (bursae) of the foot are subject to pain from inflammation. Inflammation can occur in the bursae as bursitis and in the tendons as tendinitis. Both may cause pain in the heel and it may be difficult to distinguish between the two. Enthesitis, inflammation of entheses, the sites where tendons or ligaments attach to bone, may be more common in people with other musculoskeletal conditions such as plantar fasciitis, Achilles’ tendinitis or arthritis.
  
  
• Athlete’s foot (tinea pedis). A fungal skin infection that usually occurs between the toes. The fungus grows in warm, moist places such as showers or locker rooms and can spread on the feet because shoes also provide an environment that encourages fungal growth. Athlete’s foot involves itchy, scaly skin, followed by inflammation and blisters that can be swollen and painful.
  
  
• Nerve problems. A pinched nerve in the leg or back – for example, sciatica resulting from a herniated disc, spinal stenosis or degenerative disc disease – can cause pain radiating to the foot. Other causes of nerve pain in the foot can include:
  
• • Neuroma. An abnormal swelling or growth on a nerve. It may cause a burning sensation in the foot, pain between the toes or a sensation of a stone in the shoe.
    
    
  • Tarsal tunnel syndrome. Similar to the carpal tunnel syndrome that affects the wrist, but it is caused by compression of a nerve in the foot and may cause pain along the bottom of the foot.
    
    
  • Complex regional pain syndrome. A chronic pain condition in a leg (or arm) that usually occurs after significant trauma to the limb.

• Congenital conditions. Many patients are born with flat plantar arches or high-arched feet, which themselves may not cause pain but predispose to a number of other conditions that can cause pain. Inherited diseases such as Charcot-Marie-Tooth disease, which damages the peripheral nerves, can cause foot pain and weakness.
  
  
• High cholesterol. A painful Achilles tendon may signal a common but little-known inherited condition involving excess cholesterol, familial hypercholesterolemia. This condition involves deposits of cholesterol in the tendons as well as the arteries.