The sensation that your blood is burning is a physical manifestation of nerve distress, often described clinically as a burning type of pain or dysesthesia. This feeling is not caused by the blood reaching a high temperature. It signals that sensory nerves responsible for detecting heat and pain are being irritated or damaged, causing them to misfire and send false signals to the brain. Understanding the underlying cause is the first step toward managing this symptom.
How Nerves Translate Pain into Burning
The body senses temperature and damage using specialized sensory structures called nociceptors, found throughout the skin and internal tissues. These receptors communicate via distinct nerve fibers. Unmyelinated C-fibers are primarily responsible for transmitting the slow, dull, and burning types of pain sensation. When stimulated, these fibers signal the brain to interpret the feeling as heat, even if no external heat source is present.
Nerve damage or irritation, known as neuropathy, causes these fibers to become hyper-excitable and lowers their activation threshold. An inflammatory process, driven by substances like prostaglandins and cytokines, can further sensitize the nerve endings. This state can result in allodynia, where a light touch or gentle breeze is perceived as a painful, burning sensation.
When the pain response becomes exaggerated, it is called hyperalgesia, meaning a mildly painful stimulus produces an intense, disproportionate reaction. In both allodynia and hyperalgesia, the brain receives an amplified or false signal from a dysfunctional nervous system. The persistent misfiring of these thermal nociceptors is the physiological reason the pain feels distinctly like a deep, internal burning.
Systemic Causes of Widespread Burning Sensations
The most common systemic explanation for widespread burning sensations, particularly in the hands and feet, is peripheral neuropathy. This condition involves damage to the nerves outside the brain and spinal cord, often beginning in the longest nerve fibers that reach the extremities. Between 50% and 66% of individuals with diabetes mellitus eventually develop peripheral neuropathy due to prolonged exposure to high blood sugar levels.
Excess glucose in the bloodstream damages the tiny blood vessels that supply the nerves, a process called microvascular injury. High blood sugar also leads to the formation of advanced glycation end products (AGEs), which directly impair nerve structure and function. This damage typically creates a symmetrical, stocking-and-glove pattern of burning, tingling, and numbness, starting in the toes and feet.
Several autoimmune disorders can mistakenly target and damage the peripheral nerves. Conditions such as systemic lupus erythematosus or rheumatoid arthritis involve the immune system attacking healthy tissues, including the nerve sheaths or the nerve itself. The resulting inflammation interferes with normal signal transmission, leading to sensory symptoms like burning.
Nutritional deficiencies, particularly a lack of Vitamin B12, can disrupt nerve health and function. B12 is necessary for maintaining the myelin sheath that protects nerve fibers, and its deficiency can lead to demyelination and subsequent neuropathy. Metabolic or hormonal imbalances, such as thyroid dysfunction, can also disrupt the body’s environment and contribute to generalized nerve dysfunction.
Localized and Vascular Explanations
When the burning sensation is confined to specific areas rather than being body-wide, it often points toward a localized issue or a vascular problem. One notable condition is erythromelalgia, characterized by intense, episodic burning pain, visible redness, and increased skin temperature, primarily in the feet and hands. This disorder is often linked to an underlying vascular dysfunction that causes excess blood flow to the extremities, leading to nerve irritation.
Primary erythromelalgia is sometimes caused by a genetic mutation in the SCN9A gene, which codes for a voltage-gated sodium channel (Nav1.7) in nociceptive neurons. This mutation causes these pain-sensing nerves to be hyperexcitable, meaning they fire more easily and signal pain in response to mild stimuli. The burning episodes can be triggered by activities like exercise, standing, or exposure to warmth.
Localized burning may also stem from nerve entrapment syndromes, where a specific nerve is compressed. A common example is Carpal Tunnel Syndrome, which causes burning, tingling, and numbness in the hand due to compression of the median nerve at the wrist. Similarly, sciatica results from the compression of the sciatic nerve roots in the lower back, often causing a radiating, burning pain down the leg.
A sudden, intense burning on the skin can also be a sign of a localized infection, such as cellulitis, a bacterial infection of the deeper layers of skin. The burning is accompanied by warmth, swelling, and redness at the site of infection, as the intense inflammatory response directly irritates the sensory nerve endings.
External and Medication-Related Triggers
Some burning sensations are transient and linked to external factors or temporary side effects of medical treatments. Certain medications are neurotoxic and can induce a temporary form of peripheral neuropathy. Specific chemotherapy agents commonly cause a dose-dependent burning and tingling, typically in the hands and feet, which may resolve after treatment ends.
Certain antibiotics, such as metronidazole and some fluoroquinolones, have also been associated with sensory neuropathy that includes a burning component. Symptoms often stabilize or improve once the offending drug is discontinued. Excessive intake of certain vitamins, such as high doses of Vitamin B6, can also lead to nerve toxicity that manifests as burning pain.
Intense physical activity can temporarily cause a burning feeling in the muscles due to the accumulation of metabolic byproducts like lactic acid. This acid buildup stimulates nociceptors within the muscle tissue, signaling a burning sensation that subsides quickly with rest. Direct contact with chemical irritants or severe sunburn can also cause a superficial burning sensation by activating thermal nociceptors in the skin.
When to Seek Professional Medical Advice
While the burning sensation may be alarming, it is important to assess the urgency of the symptoms. If the burning is chronic, worsening over time, or linked to a known condition like diabetes, a scheduled consultation with a healthcare provider is appropriate. This allows for a thorough evaluation, including blood tests for vitamin deficiencies, thyroid function, or underlying systemic disease, and potentially nerve conduction studies.
Certain “red flag” symptoms accompanying the burning sensation warrant immediate medical attention. You should seek emergency care if the burning pain suddenly appears alongside severe weakness, difficulty breathing, or rapidly spreading numbness. Other serious signs include a high fever, sudden loss of consciousness, or a new inability to control bladder or bowel function. These acute symptoms may indicate a serious or rapidly progressing neurological condition that requires urgent diagnosis and treatment.