Yes, an MRI can burn your skin, though it’s rare. The machine uses powerful radiofrequency energy to create images, and under certain conditions, that energy concentrates in a small area and generates enough heat to cause a real burn. Over a 10-year period, the FDA received about 1,548 adverse event reports related to MRI systems, and thermal injuries were the most commonly reported serious event, making up 59% of those reports. Relative to the tens of millions of MRI scans performed each year, the odds are extremely low, but the risk is real and largely preventable.
How an MRI Creates Heat
An MRI scanner sends radiofrequency waves into your body to generate images. When those waves hit your conductive tissue, they create tiny electrical currents called eddy currents. These currents produce heat, much the same way a wire heats up when electricity flows through it. Normally, this heat is spread across a large area and your blood circulation dissipates it without any problem.
Burns happen when that energy gets concentrated in a small spot instead of spreading evenly. Two main mechanisms cause this. The first is the “loop effect”: if two parts of your skin are touching, like your thighs pressed together or your arm resting against your torso, the contact point creates a closed electrical loop. The induced currents funnel through that narrow contact point and generate intense local heat. The second is the “antenna effect”: any conductive material of the right length can act like an antenna, absorbing radiofrequency energy and converting it to heat at its tip or along its surface.
The electric field inside the scanner isn’t uniform either. It’s strongest near the edges of the transmit coil, which means body parts positioned near the ends of the scanner bore are at higher risk of heating.
What an MRI Burn Looks and Feels Like
Most people who get burned during an MRI first notice a localized sensation of heat during the scan itself. Immediately afterward, the spot typically appears red and feels tender. In mild cases, the redness fades within hours or days. In more serious cases, the injury progresses. One documented case involved a patient who felt heat at her elbow during the scan and noticed redness right away. That burn was eventually diagnosed as a stage III burn with thick dead tissue requiring eight weeks of wound care and topical antibiotics to heal.
In another case, a man developed second-degree burns on both thighs after an MRI. His initial redness evolved into blistering eruptions about a week later. This delayed worsening is important to know about: an MRI burn can look minor at first and then develop into something more serious over the following days.
Skin-to-Skin Contact Is a Common Cause
The simplest and most preventable cause of MRI burns is body parts touching each other. When your bare skin forms a bridge, like crossed ankles, inner thighs pressing together, or fingers interlocked, the radiofrequency currents converge at those contact points. This can happen even when the scanner is operating within all standard safety limits.
MRI facilities prevent this by placing padding between your legs, arms, and torso before the scan. If you’re ever positioned inside the scanner without padding and you notice two skin surfaces are touching, it’s worth mentioning to the technologist. Keeping a small gap, even just a thin layer of cloth or foam, breaks the electrical loop and eliminates the risk.
Clothing That Can Cause Burns
Some clothing contains hidden metallic fibers that are invisible to the eye and unlabeled on the tag. In one reported case, a patient wore what appeared to be a normal undershirt made of Coolmax and Lycra. Nothing on the label indicated it contained metal. Only after the burn occurred and the manufacturer was contacted did it come to light that the fabric was impregnated with silver microfibers for antimicrobial and moisture-wicking purposes.
Silver-infused textiles have become increasingly common in athletic and “tech” clothing. They’re marketed for odor control and antibacterial properties, and they appear in products from major brands including Reebok, Adidas, and New Balance. Copper-infused fabrics are also growing in popularity for socks, shirts, and undergarments. These metallic fibers interact with the MRI’s radiofrequency field the same way any conductor does, absorbing energy and generating heat against your skin.
This is the main reason MRI facilities ask you to change into a hospital gown. Even if your clothes seem metal-free, the safest approach is to wear only facility-provided garments.
Medication Patches and Topical Products
The FDA has specifically warned that transdermal medication patches, the adhesive patches used to deliver drugs through the skin, can overheat during an MRI if their backing contains aluminum or other metals. This applies to various types of patches including those used for pain relief, nicotine replacement, and hormone therapy. The metal in the backing absorbs radiofrequency energy and heats up directly against the skin, potentially causing a burn at the patch site. You should remove any medication patches before a scan, or at least inform the technologist so they can assess the risk.
Tattoos and Permanent Makeup
Tattoo-related MRI reactions are a source of ongoing concern, though the actual risk appears to be low. Some tattoo inks, particularly those used in permanent makeup like eyeliner or lip liner, contain iron-based minerals such as magnetite, goethite, and hematite. Contaminants like nickel and chromium have also been found. These magnetic particles can respond to the MRI’s fields and potentially stimulate nerve endings around the pigment, causing a burning or stinging sensation.
That said, research specifically measuring temperature changes in tattoo ink during MRI has not confirmed clinically significant heating. A study analyzing inks with high iron concentrations found no meaningful temperature increase and no physical movement of the pigment. The sensation some tattooed patients report may come from electrical stimulation of nearby nerve fibers rather than actual thermal injury. If you have tattoos, you can still get an MRI. Inform the technologist, and if you feel any unusual warmth or discomfort during the scan, let them know immediately so they can pause if needed.
Why Body Weight Matters
The amount of radiofrequency energy your body absorbs during an MRI is measured by a value called the Specific Absorption Rate, or SAR. Your body weight directly influences this number. Research comparing patients above and below 60 kilograms (about 132 pounds) found a statistically significant difference in SAR values between the two groups, with a strong correlation between weight and energy absorption. The MRI system adjusts its output based on the weight you or the technologist enters before the scan, which is why getting that number right matters. An inaccurate weight entry could cause the machine to deliver more energy than your body can safely dissipate.
How to Reduce Your Risk
- Change into a gown. Remove all personal clothing, especially athletic wear and undergarments that might contain metallic fibers you can’t see or feel.
- Remove patches and accessories. Take off medication patches, hearing aids, jewelry, hair clips, and any other items that could contain metal.
- Accept the padding. Allow technologists to place foam or towels between your arms, legs, and torso. If you don’t feel adequately padded, ask for more.
- Keep still and keep separated. Avoid crossing your legs, clasping your hands, or letting any two bare skin surfaces press together.
- Speak up during the scan. You’ll typically have a call button or intercom. If you feel any localized warmth, tingling, or discomfort, alert the technologist right away. The scan can be paused or stopped within seconds.