Why Do I Feel Like I’m Burning Inside?

An internal burning sensation can arise from dozens of different medical conditions, and figuring out which one applies to you depends heavily on where you feel it, how long it lasts, and what else is going on in your body. The most common culprit is acid-related irritation in the esophagus or stomach, but burning can also signal nerve damage, hormonal shifts, autoimmune inflammation, or even changes in how your brain processes pain. Because the causes span so many body systems, no single explanation covers everyone who types this question into a search bar.

When the Burning Comes From Your Gut

The most familiar form of internal burning is heartburn, and it is far more complicated than “acid eating a hole in your esophagus.” For years, the accepted explanation was straightforward: stomach acid leaked upward, broke through the lining, and activated pain receptors in the deeper tissue. A key receptor involved, called TRPV1, sits on nerve fibers in the esophagus and responds to acid. Research has confirmed that TRPV1-positive nerve fibers increase in inflamed esophageal tissue, and applying capsaicin (the compound that makes chili peppers hot) directly to a healthy esophagus produces dose-dependent heartburn symptoms through the same receptor.¹

But this acid-damage model has a glaring problem: a large group of people with classic heartburn symptoms have no visible damage to their esophageal lining at all. These patients, sometimes described as having non-erosive reflux disease, experience burning that is just as severe as people with obvious tissue erosion, yet their acid exposure is measurably lower. The burning they feel is real, but it does not come from acid chewing through tissue in the traditional sense.¹ One proposed mechanism involves repeated exposure to even mildly acidic reflux, which gradually ramps up the expression of certain inflammatory receptors on the esophageal lining, eventually triggering inflammation from the epithelial cells themselves.²

A related condition, functional dyspepsia, produces burning pain in the upper abdomen without any ulcer or structural abnormality. Patients with this condition have lowered pain thresholds in the stomach, meaning normal levels of gastric stretching or acid exposure register as painful. Immune cells in the gut wall release compounds like histamine and tryptase that make nearby nerve fibers more excitable, while a weakened barrier in the upper small intestine lets irritants reach the immune system more easily, keeping inflammation simmering.³ If your burning is centered in the chest or upper stomach, one of these gut-related conditions is statistically the most likely explanation.

Nerve Damage and Small Fiber Neuropathy

When the burning is in your hands, feet, or skin rather than your chest, the problem often traces to damaged small nerve fibers. These are the thinnest nerve fibers in your body, responsible for sensing temperature and pain. When they malfunction or degenerate, the signals they send become disordered: you feel burning, tingling, or pins-and-needles in areas where nothing is physically hot or injured.

Diabetes is one of the most common drivers. Chronic high blood sugar damages small nerve fibers over time, producing what is typically described as burning, shooting, or tingling pain concentrated in the feet and hands.⁴ But you do not need a diabetes diagnosis for this to happen. Vitamin B12 deficiency can produce similar nerve damage because B12 is essential for building myelin, the insulating sheath around nerve fibers. Without adequate B12, myelin synthesis falters and both sensory and neuropsychiatric symptoms can follow.⁵ This is worth knowing because B12 deficiency is treatable and sometimes overlooked, especially in people who follow plant-based diets or take certain medications that interfere with absorption.

Autoimmune diseases can attack small fibers, too. In Sjögren syndrome, an autoimmune condition best known for dry eyes and dry mouth, a prospective study of 40 patients with confirmed small fiber neuropathy found that burning pain was the most common complaint, reported by 90% of the group. Numbness, tingling, and electric-discharge sensations were also widespread.⁶ Because standard nerve conduction tests only measure large fiber function, small fiber damage frequently goes undetected in routine testing, leaving patients to wonder why they feel so much pain despite “normal” results.

How Small Fiber Neuropathy Gets Diagnosed

If standard nerve conduction studies come back normal but you still have burning and tingling, a skin biopsy can pick up what those tests miss. A small punch biopsy, usually from the lower leg, allows a lab to count the density of nerve fibers in the top layer of skin. In one study, skin biopsy detected abnormalities in about 88% of patients who had sensory neuropathy symptoms but normal nerve conduction results, compared with only 10% of healthy controls.⁷ The procedure has become a well-validated method for confirming small fiber neuropathy when other tests cannot explain the burning you feel.⁸

Hormonal Shifts That Feel Like Internal Fire

If you are perimenopausal or menopausal and the burning comes in waves, often centered in your chest and face, hot flashes are the likely explanation. Hot flashes are not just “feeling warm.” They are a rapid heat-dissipation response involving sudden sweating, blood vessel dilation near the skin surface, and a distinct feeling of intense internal heat.⁹

What actually happens is that the body’s thermostat narrows its comfort range. Normally, your brain tolerates a modest range of core temperature variation before triggering sweating or shivering. During menopause, the drop in estrogen shrinks that zone dramatically, so even a tiny uptick in body temperature sets off a full-blown sweating and flushing episode. The process involves a cascade of brain chemicals including noradrenaline, serotonin, and neuropeptides like neurokinin B, all of which become dysregulated when estrogen drops.¹⁰ People undergoing medical treatments that suppress estrogen or testosterone, such as hormone therapy for breast or prostate cancer, can experience the same phenomenon.

When the Brain Itself Amplifies the Burning

Some people feel widespread burning that does not map neatly to one organ or one set of nerves. In fibromyalgia, the central nervous system becomes sensitized so that ordinary signals get amplified into pain. This is not imaginary pain. It reflects a measurable change in how spinal cord neurons respond to repeated input from pain fibers. When those fibers are stimulated repeatedly, spinal neurons ramp up their response instead of tuning it out, and this heightened state persists even after the stimulation stops. Research has shown that this central sensitization is widespread along the spinal cord in fibromyalgia patients.¹¹ Patients describe the resulting sensation as flu-like muscle aches and generalized pain that simply does not resolve.¹²

Central sensitization is not unique to fibromyalgia. It can develop after any persistent painful condition if pain signals hammer the spinal cord long enough. This is why early treatment of conditions that cause burning is considered important: the longer pain persists, the greater the risk that the nervous system starts amplifying it independently of the original cause.

Infections That Leave Burning Behind

Shingles is a well-known cause of burning skin pain. The varicella zoster virus, the same one that causes chickenpox, hides in nerve clusters for decades. When the immune system weakens due to age, stress, or illness, the virus can reactivate and produce a painful blistering rash along a strip of skin. About a third of the population will develop shingles at some point, with risk climbing steeply in older age.¹³ In some people, burning pain persists long after the rash clears, a condition called postherpetic neuralgia that can last months or years.

COVID-19 has added a newer entry to this category. Some people with long COVID develop patches of burning or itching skin that come and go in unpredictable locations rather than following the usual nerve pathways. Biopsies from affected patients have revealed swollen nerve bundles in the deeper skin layers, and researchers have proposed that the virus damages both myelinated and unmyelinated sensory fibers, producing patchy sensory disturbance that skips around the body.¹⁴ This pattern, burning pain that does not respect neat anatomical boundaries, can be genuinely alarming if you do not know it has been documented.

Medications and Toxins That Damage Nerves

Certain chemotherapy drugs are notorious for causing burning sensations in the hands and feet. The mechanism is not that they attack nerves directly in the way you might expect. Instead, drugs like paclitaxel cause mitochondria inside nerve fibers to swell and malfunction, disrupting the energy supply that nerves need to signal properly. Animal studies showed that paclitaxel increased the number of swollen, abnormal mitochondria in pain fibers by roughly two-fold, and the burning pain behavior tracked closely with those mitochondrial changes rather than with any breakdown of nerve structure itself.¹⁵ Other chemotherapy agents like cisplatin and vincristine damage nerve mitochondria through different routes, but the end result is similar: disrupted calcium handling, energy failure in the nerve, and burning pain.¹⁶

Chemotherapy is the best-studied example, but other medications can do this too. Certain antibiotics, antiviral drugs, and antiretroviral medications carry small fiber neuropathy as a known side effect. If burning in your extremities started within weeks or months of beginning a new medication, that timing is worth mentioning to your doctor.

Rarer Conditions That Cause Burning

Two less common but distinctive conditions deserve mention because they are easy to miss if no one is looking for them.

Erythromelalgia causes episodes of intense burning pain with visible redness and warmth, usually in the feet or hands. In its inherited form, it is caused by gain-of-function mutations in a sodium channel called Nav1.7, which is concentrated in pain-sensing and sympathetic neurons. The mutations make these channels too easy to activate, so nerve fibers fire pain signals at a lower threshold than normal.¹⁷ Episodes are typically triggered by warmth or exercise, and cold water immersion is one of the few things that reliably provides relief.

Burning mouth syndrome is exactly what it sounds like: a persistent burning sensation on the tongue, lips, or palate without any visible sores or lesions. For a long time it was poorly understood, but research using tongue biopsies found that patients had significantly fewer nerve fibers in the surface tissue of the tongue compared to healthy people, and the remaining fibers showed signs of degeneration. The study concluded that burning mouth syndrome is caused by a small fiber neuropathy of the trigeminal nerve, the nerve that serves the face and mouth.¹⁸ This finding matters because it moves the condition out of the “it’s all in your head” category and into the realm of identifiable nerve damage.

Why So Many Different Conditions All Feel Like Burning

It might seem strange that acid reflux, nerve damage, hormone changes, and autoimmune disease all produce the same burning sensation. The reason is that your body has a family of ion channels, including at least 28 identified transient receptor potential channels, that respond to temperature, chemicals, and tissue damage.¹⁹ The same receptor that registers actual heat from a flame (TRPV1, mentioned earlier in the context of heartburn) also responds to acid, capsaicin, and certain inflammatory molecules. When any of these triggers activate TRPV1 or its relatives, your brain interprets the signal as burning heat whether the source is a hot stove, stomach acid, or an inflamed nerve. In a sense, “burning” is your nervous system’s default vocabulary for a broad category of tissue insult.

This convergence also explains why burning pain can feel so confusing to describe. You might say “it burns but there’s no heat” or “it feels like sunburn under the skin,” and both of those are accurate descriptions of what is happening at the receptor level. The same molecular alarm system is going off, just triggered by something other than actual heat.

Treatment Approaches for Burning Pain

Treatment depends entirely on the cause. Acid-related burning typically responds to acid-suppressing medications and dietary changes. Hot flashes often improve with hormone therapy or newer drugs targeting the neurokinin pathway. But for neuropathic burning, the kind caused by nerve damage or central sensitization, the pharmacological toolkit is more specialized.

The most commonly prescribed medications for neuropathic burning pain are gabapentinoids (gabapentin and pregabalin) and the antidepressant duloxetine. These work through completely different mechanisms: gabapentinoids reduce the release of excitatory brain chemicals by modulating calcium channels on nerve terminals, while duloxetine strengthens the body’s natural pain-damping pathways that run from the brainstem down the spinal cord.²⁰ Newer gabapentinoid compounds have been developed specifically for conditions like diabetic neuropathic pain, where burning, shooting, and tingling sensations erode quality of life.²¹

For people who do not respond well to medications, neuromodulation is an increasingly used option. This involves electrically stimulating peripheral nerves or the spinal cord to interrupt or override pain signals. The technology has improved with higher-frequency stimulators and closed-loop systems that adjust automatically, though researchers are candid that the mechanisms behind why spinal cord stimulation works remain poorly understood even as clinical outcomes continue to improve.²²

When to Take Internal Burning Seriously

Occasional heartburn after a heavy meal or a fleeting hot flash during menopause rarely signals anything dangerous. But burning that persists for weeks, wakes you from sleep, appears in your hands or feet, or does not respond to over-the-counter antacids deserves medical attention. The same applies if burning spreads to areas it did not originally affect, follows an unusual pattern across the skin, or comes paired with numbness, weakness, or difficulty walking. These patterns often point toward neuropathic causes where early identification and treatment of the underlying condition, whether it is diabetes, a vitamin deficiency, an autoimmune disease, or medication toxicity, can slow or stop the nerve damage. Burning that gets dismissed as stress or anxiety sometimes turns out to have a measurable, treatable origin once someone orders the right test.