Why Do My Knees and Legs Feel Hot? Causes

• Burns
  • Chemical burns
  • Electrical burns
  • Thermal burns, such as sunburn
• Inflammation
  • Ankylosing spondylitis (a type of arthritis leading to inflammation of the spine)
  • Bursitis (inflammation of the protective closed, fluid-filled sacs around the joint)
  • Chondromalacia (softening and breakdown of the kneecap cartilage)
  • Gout (a painful type of arthritis caused by the accumulation of uric acid in the joints)
  • Infectious arthritis (joint inflammation caused by an infection)
  • Osteoarthritis (joint inflammation due to wear and tear of the joint cartilage)
  • Psoriatic arthritis (arthritis associated with the autoimmune disease, psoriasis)
  • Rheumatoid arthritis (a chronic autoimmune and inflammatory disease characterized by inflammation in the joints)
  • Systemic lupus erythematosus (an autoimmune disease, wherein the body attacks its healthy cells and tissues)
• Neurological causes
  • Nerve entrapment or compression
    • May occur due to:
      • Back injuries
      • Age-related degenerative changes of the spine
      • Use of chemotherapy drugs
      • Exposure to toxins
• Peripheral neuropathy 
  • Occurs due to damage to the peripheral sensory nerves connecting the spinal cord to the extremities.
  • Diabetes and alcohol abuse are the two most common causes.
  • Other conditions that may cause peripheral neuropathy include:
    • Chemotherapy drugs
    • Hereditary diseases
    • Autoimmune disorders
    • Exposure to toxic chemicals
    • Infections
    • Kidney failure
    • Nutritional imbalances (vitamin B12 deficiency, malabsorption syndrome)
• Tarsal tunnel syndrome
  • Compression of the posterior tibial nerve inside the tarsal tunnel (a narrow space inside the ankle near the ankle bones) can result in sensations of burning, tingling, or pain in parts of the feet.
• Morton’s neuroma
  • Occurs due to the thickening of the nerve tissues between the bones at the base of the toes, resulting from:
    • Tight shoes
    • Sports injuries
    • Stress on the foot
    • Abnormal position or movement of the foot
• Vascular causes
  • Peripheral artery disease
    • When the arterial supply to the legs is compromised, it leads to inadequate oxygen delivery to the tissues in the legs.
    • It is characterized by claudication (leg pain while walking) and a burning sensation in the legs.
• Endocrine issues
  • Diabetes mellitus
    • Type I and II diabetes can affect the peripheral nerves of the body, especially the sensory nerves of the feet and legs.
    • High blood glucose levels due to uncontrolled diabetes can cause both nerve and blood vessel damage.
  • Hypothyroidism
    • An underactive thyroid gland can lead to the sensation of burning in the feet, along with weight gain, dry skin, or fatigue.
• Infections
  • Athlete’s foot (tinea pedis)
    • This infection is caused by fungi called dermatophytes, which thrive in moist, warm areas of the skin.
    • Damp shoes and socks and humid environments are most favorable for the fungi to grow and spread.

Depending on the underlying cause, other symptoms that may accompany a burning sensation in the knees or legs include the following:

• Localized symptoms
  • Joint stiffness
  • Leg pain and swelling or numbness
  • Muscle weakness
  • Redness or warmth in the affected joint
  • Skin blistering or oozing fluid
  • Tingling sensation in the extremities
• General symptoms
  • Fever
  • Burning sensation in other areas of the arms or legs
  • Pain in the shoulder, arm, hand, or fingers
  • Stiffness or swelling of other joints

Most cases of burning legs have an obvious cause (such as diabetes). The diagnosis of burning feet due to neuropathy is straightforward and additional testing is generally not required.

In a few cases, however, if the burning sensation is sudden or has no explainable cause, further testing may be needed to make a correct diagnosis. These tests may include:

• Physical examination and history: Involves taking a detailed medical history, asking about physical symptoms and current medications, and a physical examination of reflexes and signs of infection and injury.
• Blood tests: Measure blood glucose level or screen for nutritional deficiencies or endocrine disorders
• Nerve function tests:
  • Electromyography: Measures the electrical activity of a muscle in response to nerve stimulation
  • Nerve conduction velocity test: Assesses the speed at which electrical impulses move along a nerve
  • Nerve biopsy: In rare cases, a doctor may suggest cutting a piece of nerve tissue and examining it under a microscope

Treatment of burning in the legs depends on the underlying cause and may include:

• Medications
  • Analgesics: Oral or topical narcotic or nonnarcotic medications to relieve pain
  • Antidepressants: Tricyclic antidepressants to help relieve chronic pain associated with neuropathy
  • Anticonvulsant drugs: Gabapentin, carbamazepine, and pregabalin to treat chronic pain
  • Insulin or oral antidiabetic drugs: To control blood glucose levels in people with diabetes
  • Nutritional supplements: For people with vitamin deficiencies
  • Antifungal drugs: Diflucan (fluconazole), Sporanox (itraconazole) and Naftin (naftifine) to help relieve burning feet caused by athlete's foot
  • Oral thyroid hormone medicines: For hypothyroidism
• Self-care
  • Physical therapy and exercise
  • Dietary modifications
  • Soaking your feet in cool water for at least 15 minutes for a temporary relief
  • Avoiding exposure to high heat or extremes of temperature
  • Elevating your legs and feet
  • Taking over-the-counter pain medicines (nonsteroidal anti-inflammatory drugs, such as ibuprofen, ketoprofen, or naproxen, for temporary pain relief)
  • Limiting alcohol consumption
  • Wearing compression stockings for venous insufficiency

Burning sensation in the legs can be due to serious diseases, and failure to seek treatment can result in serious complications and permanent damage:

• Joint deformity
• Permanent loss of sensation
• Chronic pain
• Disability
• Decreased quality of life

If your symptoms appear suddenly or get worse, contact a doctor as burning legs could be a sign of an underlying medical condition.