Burning feet syndrome is a distressing symptom characterized by sensations of heat, tingling, or pain in the feet, often most pronounced at night. While it may seem like a localized issue, burning feet can be a manifestation of a wide array of systemic, neurological, vascular, and dermatological conditions. Understanding the underlying causes is essential for accurate diagnosis and effective treatment.

Neurological Causes

Neuropathy is the most common cause of burning feet, particularly peripheral neuropathy, which affects the nerves outside the brain and spinal cord.

1. Diabetic Peripheral Neuropathy

Diabetes mellitus is the leading cause of peripheral neuropathy worldwide. Chronic hyperglycemia leads to microvascular damage and metabolic dysfunction in peripheral nerves, resulting in sensory disturbances such as burning, tingling, and numbness. The feet are typically affected first due to the length-dependent nature of the neuropathy.

2. Alcoholic Neuropathy

Chronic alcohol consumption can lead to nutritional deficiencies, particularly of thiamine (vitamin B1), and direct neurotoxicity. This results in a symmetric distal neuropathy, often presenting with burning sensations in the feet.

3. Chemotherapy-Induced Neuropathy

Certain chemotherapeutic agents, such as paclitaxel, vincristine, and cisplatin, are neurotoxic and can cause burning pain in the feet. This is often dose-dependent and may persist long after treatment cessation.

4. Idiopathic Small Fiber Neuropathy

Small fiber neuropathy affects the unmyelinated C fibers and thinly myelinated A? fibers responsible for pain and temperature sensation. Patients often report burning pain without obvious cause, and diagnosis may require specialized testing such as skin biopsy or quantitative sensory testing.

Metabolic and Nutritional Causes

Metabolic disorders and nutritional deficiencies can impair nerve function and contribute to burning feet.

1. Vitamin Deficiencies

• Vitamin B12 Deficiency: Essential for myelin synthesis and nerve function. Deficiency can lead to subacute combined degeneration of the spinal cord and peripheral neuropathy.
• Vitamin B6 Toxicity: Paradoxically, excessive intake of pyridoxine can cause sensory neuropathy, including burning sensations.
• Niacin (Vitamin B3) Deficiency: Pellagra, caused by niacin deficiency, presents with dermatitis, diarrhea, dementia, and burning feet.

2. Hypothyroidism

Thyroid hormone deficiency can lead to fluid retention and tissue edema, compressing peripheral nerves and causing neuropathic symptoms. Additionally, hypothyroidism may impair nerve metabolism.

3. Chronic Kidney Disease (Uremia)

Uremic neuropathy is a common complication of end-stage renal disease. Accumulation of metabolic waste products can damage peripheral nerves, leading to burning feet and other sensory disturbances.

Infectious Causes

Certain infections can directly or indirectly affect peripheral nerves.

1. HIV Neuropathy

HIV-associated distal sensory polyneuropathy is common, especially in advanced stages or in patients on neurotoxic antiretroviral therapy. Burning feet are a hallmark symptom.

2. Leprosy

Caused by Mycobacterium leprae, leprosy affects peripheral nerves, particularly in cooler areas of the body like the feet. Neuropathy may present with burning pain, numbness, and muscle wasting.

3. Herpes Zoster (Shingles)

Reactivation of varicella-zoster virus in sensory ganglia can cause postherpetic neuralgia, which may include burning pain in the affected dermatome, sometimes involving the feet.

Vascular and Circulatory Causes

Impaired blood flow or vascular inflammation can contribute to burning sensations in the feet.

1. Peripheral Arterial Disease (PAD)

PAD reduces blood flow to the extremities, leading to ischemic pain, which may be perceived as burning. Symptoms typically worsen with exertion and improve with rest.

2. Erythromelalgia

A rare vascular disorder characterized by episodic burning pain, redness, and warmth in the feet. It is often triggered by heat or exercise and may be associated with myeloproliferative disorders.

3. Venous Insufficiency

Chronic venous insufficiency can lead to pooling of blood in the lower extremities, causing inflammation and discomfort, sometimes described as burning.

Dermatological Causes

Skin conditions affecting the feet can also produce burning sensations.

1. Contact Dermatitis

Exposure to allergens or irritants in footwear, topical agents, or environmental substances can cause inflammation and burning pain.

2. Tinea Pedis (Athlete’s Foot)

Fungal infections of the feet often present with itching, burning, and scaling. Interdigital maceration and erythema are common findings.

3. Eczema and Psoriasis

Inflammatory skin conditions may involve the feet and cause burning, especially when lesions are fissured or infected.

Psychogenic and Idiopathic Causes

In some cases, burning feet may occur without identifiable pathology.

1. Burning Feet Syndrome (Grierson-Gopalan Syndrome)

A rare idiopathic condition characterized by burning pain in the feet, often worse at night. It may be associated with psychological stress, hormonal changes, or autonomic dysfunction.

2. Psychogenic Pain

Chronic pain syndromes such as somatoform disorders or functional neurological disorders may present with burning sensations in the absence of organic pathology.

Diagnostic Considerations

Given the broad differential diagnosis, a thorough clinical evaluation is essential. Key steps include:

• History: Onset, duration, progression, associated symptoms, systemic illnesses, medication use, and lifestyle factors.
• Physical Examination: Neurological assessment, vascular evaluation, dermatological inspection.
• Laboratory Tests: Blood glucose, renal function, thyroid profile, vitamin levels, infectious disease screening.
• Electrodiagnostic Studies: Nerve conduction studies and electromyography to assess large fiber involvement.
• Skin Biopsy: For small fiber neuropathy.
• Imaging: MRI or CT if central nervous system pathology is suspected.

Management Strategies

Treatment depends on the underlying cause. General approaches include:

• Addressing the Root Cause: Glycemic control in diabetes, vitamin supplementation, treating infections.
• Symptomatic Relief: Gabapentin, pregabalin, duloxetine, and topical agents like capsaicin or lidocaine.
• Lifestyle Modifications: Foot hygiene, proper footwear, avoiding heat triggers.
• Multidisciplinary Care: Involving podiatrists, neurologists, endocrinologists, and pain specialists.

Burning feet is a symptom with a complex and diverse etiology, ranging from common conditions like diabetes to rare syndromes such as erythromelalgia. Accurate diagnosis requires a methodical approach, integrating clinical findings with targeted investigations. For podiatrists and other healthcare professionals, understanding the multifactorial nature of burning feet is crucial for delivering effective, patient-centered care. As research continues to uncover new mechanisms and treatments, the prospects for managing this challenging symptom continue to improve.