Overview of Foot and Ankle Disorders: Foot and Ankle Disorders: Merck Manual Professional

Foot Manifestations of Systemic Disorders
Foot Symptoms or Signs	Possible Cause
Pain at rest (feet elevated), relieved by dependency	End-stage peripheral arterial disease
Cold, red, or cyanotic feet	Advanced arterial ischemia
Episodically red, hot, very painful feet	Erythromelalgia—idiopathic (most commonly) or secondary to various disorders (eg, myeloproliferative disorders, which are rare)
Foot pain that becomes severe within seconds or possibly minutes, particularly in patients with atrial fibrillation; foot often cool	Embolic arterial occlusion
Cyanosis of a single toe (blue toe syndrome)	Thromboembolic disease due to aortic-iliac stenosis, arrhythmia, or cholesterol embolization (after coronary artery bypass or catheterization) Warfarin therapy
Bilateral episodic digital discomfort, pallor, and cyanosis	Raynaud syndrome
Bilateral painless cyanosis in a young female	Acrocyanosis
Bilateral edema	Renal, hepatic, or cardiac dysfunction Drugs (eg, Ca channel blockers)
Unilateral edema	Deep venous thrombosis Lymphatic obstruction
Firm nonpitting foot and leg edema	Lymphedema Systemic sclerosis
Firm, nonpitting edema with nodular appearance above the malleoli	Pretibial myxedema
Edema with hemosiderin deposition and brownish discoloration	Venous insufficiency Recurrent small-vessel vasculitis
Edema of feet and toes, numbness and pain at the ankle and heel (tarsal tunnel syndrome)	Hypothyroidism Relapsing symmetric seronegative synovitis (rare)
Red, dusky patches on the dorsum with flaccid bullae (necrolytic acral erythema)	Hepatitis C Vasculitis Emboli
Isolated toe swelling and deformity (sausage digits) with pain	Psoriatic arthritis Reactive arthritis Other spondyloarthropathies Crystal-induced arthritis
Painful feet with paresthesias	Peripheral neuropathy (local or systemic—eg, diabetic neuropathy)
Pain or paresthesias in the leg and foot; pain in the foot and back when the leg is extended, relieved when the knee is flexed	Sciatica
Toe, foot, or ankle pain with warmth and redness	Gout Stress fracture
Thickened (> 22 mm) heel pad as determined with x-rays or ultrasonography	Hyperpituitarism with acromegaly

Foot Manifestations of Systemic Disorders

Foot Symptoms or Signs

Possible Cause

Pain at rest (feet elevated), relieved by dependency	End-stage peripheral arterial disease
Cold, red, or cyanotic feet	Advanced arterial ischemia
Episodically red, hot, very painful feet	Erythromelalgia—idiopathic (most commonly) or secondary to various disorders (eg, myeloproliferative disorders, which are rare)
Foot pain that becomes severe within seconds or possibly minutes, particularly in patients with atrial fibrillation; foot often cool	Embolic arterial occlusion
Cyanosis of a single toe (blue toe syndrome)	Thromboembolic disease due to aortic-iliac stenosis, arrhythmia, or cholesterol embolization (after coronary artery bypass or catheterization) Warfarin therapy
Bilateral episodic digital discomfort, pallor, and cyanosis	Raynaud syndrome
Bilateral painless cyanosis in a young female	Acrocyanosis
Bilateral edema	Renal, hepatic, or cardiac dysfunction Drugs (eg, Ca channel blockers)
Unilateral edema	Deep venous thrombosis Lymphatic obstruction
Firm nonpitting foot and leg edema	Lymphedema Systemic sclerosis
Firm, nonpitting edema with nodular appearance above the malleoli	Pretibial myxedema
Edema with hemosiderin deposition and brownish discoloration	Venous insufficiency Recurrent small-vessel vasculitis
Edema of feet and toes, numbness and pain at the ankle and heel (tarsal tunnel syndrome)	Hypothyroidism Relapsing symmetric seronegative synovitis (rare)
Red, dusky patches on the dorsum with flaccid bullae (necrolytic acral erythema)	Hepatitis C Vasculitis Emboli
Isolated toe swelling and deformity (sausage digits) with pain	Psoriatic arthritis Reactive arthritis Other spondyloarthropathies Crystal-induced arthritis
Painful feet with paresthesias	Peripheral neuropathy (local or systemic—eg, diabetic neuropathy)
Pain or paresthesias in the leg and foot; pain in the foot and back when the leg is extended, relieved when the knee is flexed	Sciatica
Toe, foot, or ankle pain with warmth and redness	Gout Stress fracture
Thickened (> 22 mm) heel pad as determined with x-rays or ultrasonography	Hyperpituitarism with acromegaly