Diseases Affecting the Foot
Several conditions, particularly rheumatic diseases, can affect the foot. In some cases, foot pain may even be the first sign of an underlying systemic disease.
Rheumatoid Arthritis
Rheumatoid arthritis is an autoimmune rheumatic disease that causes painful, inflammatory arthritis that is typically bilateral and symmetrical.
It often begins in the small joints of the extremities, and in about 25% of cases, the initial involvement affects the 4th and 5th metatarsophalangeal joints.
Over time, the disease can lead to progressive deformities of the foot, with the toes drifting outward in a characteristic “fibular drift” pattern.
Psoriatic Arthritis
Psoriasis is a chronic inflammatory skin disease characterized by red, scaly plaques and sometimes intense itching. A proportion of patients with psoriasis may develop psoriatic arthritis.
This condition can resemble either ankylosing spondylitis or rheumatoid arthritis. It may affect both axial and peripheral joints and often involves swelling of the extremities, sometimes presenting as “sausage digits” (dactylitis), where entire fingers or toes become diffusely swollen.
Calcium Pyrophosphate Deposition Disease (Pseudogout)
Calcium pyrophosphate deposition disease is a metabolic disorder characterized by the deposition of calcium crystals in the articular cartilage.
Its clinical presentation closely resembles gout and is therefore also called “pseudogout.” However, unlike gout, it is not related to dietary or lifestyle factors.
This condition is more common in women and is often associated with underlying disorders such as hyperparathyroidism.
Complex Regional Pain Syndrome (Algoneurodystrophy)
Complex regional pain syndrome (CRPS), also known as algoneurodystrophy, is a painful vasomotor and trophic disorder related to dysfunction of the autonomic nervous system, often triggered by trauma. It typically progresses through three phases.
The first is a “warm” phase, characterized by a painful, inflamed, and swollen foot, which can last from days to several months. This is followed by a “cold” phase, where pain may decrease but the foot becomes cyanotic and colder in appearance. The final phase is the sequelae stage, where structural changes, stiffness, and functional impairment may lead to reduced autonomy.
Custom orthoses may be used to support function, improve comfort, and help the patient regain a degree of mobility during recovery.
Ankylosing Spondylitis
Ankylosing spondylitis is an inflammatory rheumatic disease that mainly affects the axial skeleton, particularly the spine and pelvis.
Over time, it commonly involves the heel, leading to inflammatory heel pain (talalgia). This pain is often severe, worse at night, and associated with prolonged morning stiffness. Unlike mechanical pain, it is not related to walking distance or physical activity.
Gout
Gout is a metabolic disorder caused by impaired metabolism of uric acid, leading to its accumulation and crystal deposition in joints. It is often associated with poor dietary habits and may be seen more frequently in overweight individuals with high alcohol consumption.
It most commonly presents as a sudden, severe arthritis of the first metatarsophalangeal joint (big toe). The pain can be extremely intense, to the point where even the touch of a bedsheet becomes unbearable.
Diabetes
Diabetes leads to multiple vascular, neurological, and musculoskeletal complications, particularly affecting the foot.
From a vascular standpoint, arteries may become narrowed or blocked by atherosclerotic plaques (fatty deposits), increasing the risk of cardiovascular events such as stroke and heart attack. This impaired circulation also significantly reduces wound healing capacity, making regular podiatric follow-up essential for early detection of skin lesions or ulcer risk.
Neuropathy is another major complication, most commonly resulting in loss of protective sensation in the foot. Combined with poor healing, unnoticed injuries can become infected and develop into a plantar ulcer, which is difficult to treat and often requires hospital care. In severe cases, this can progress to gangrene and amputation.
Diabetes can also affect the bones and joints of the foot. Reduced blood flow and neurological impairment may lead to structural weakening, sometimes causing collapse of the arch (Charcot foot), resulting in deformity and further musculoskeletal complications.
Management includes regular foot care and custom orthoses to redistribute plantar pressure, reduce the risk of injury, and help limit joint deformities.