Toasted Skin Syndrome (No, I’m Not Making This Up)

Sometimes patients think that I am just making up diagnoses. This is a classic example.

I had a patient yesterday who had seen several physicians for evaluation of this strange rash on her back. She had had it for months. It didn’t hurt. It didn’t itch. It hadn’t changed. She and her husband were concerned by its appearance and by the fact that her doctor didn’t know what it was.
I took a look at her and asked one question to make the diagnosis.


“Do you use a heating pad?”

“No,” she replied, wrinkling her brow at my curious question. “Why would a heating pad cause a rash anyway?” She asked.

“It’s not the pad,” I answered, “It’s the heat.”

“Well, I do sit by the fireplace on cold nights,” she added.

“Eureka!” I exclaimed. (Well, actually I didn’t, but I thought it). “Do you sit with one side to the fire?”

“Yes, I sit with my left side to the fire while I read.”

“You have erythema ab igne,” I said.

“You’re just making that up, right?” she asked.

I’m not. Erythema ab igne, also known as toasted skin syndrome, is a red, brown rash that develops as a result of prolonged exposure to heat without an actual burn. The redness develops in a particular pattern, as seen in the photo, called reticulate or net like. Slowing of blood flow in the affected area, called hemostasis, is likely the cause.

The rash can be various colors from red to pink to brown. It improves after stopping exposure to heat, but in some instances, the brown coloring might be permanent.

Any source of prolonged heat like heating pads, water bottles, even laptop computers (if it sits on your lap) can be a cause. It is well documented in old dermatology books on the legs of women who would sit close to the fire or the pot belly stove in the winter to try to stay warm.

Ironically, my patient lives here in San Diego. Cold nights, as it turns out, are a relative thing.

86 thoughts on “Toasted Skin Syndrome (No, I’m Not Making This Up)

  1. I noticed the other day before taking my shower I had some irritation on my back kindof like the pic but more brown in color. I was freaked for a moment but I new right away it had to be from the heating pad. I stopped using it right away. I had been using the heating pad alot lately. A way to warm up and relax.It’s only been a few days but I was starting to freak a little with it still being there. Thankfully I am not alone. Looks like it’s back to good old meditation for stress for me. Wish I had known about this sooner, I wouldn’t have used the heating pad so much. There should be a warning about this condition or something. Thanks for the stories and ways to treat. Sorry to those of you in so much pain.

  2. Oh no! I think you have just described what I have done to my leg. I have a purple-ish net like pattern of veins on thigh from where my laptop has been resting, my laptop gets hot on one side where the processor is. It would come up sometimes and go away, but now it seems to be staying. I have not had my laptop on my leg for 4 days, and it still there. Is it likely that this is permanent now? Is there anything I can do to reduce it? It looks like a horrible bruise that is fading.

    Thanks in advance for any advice you can give me.

    • Thanks so much for writing. Of course, without seeing you, I can’t give you, specifically, advice. I can say that “toasted skin syndrome” tends to be temporary and resolves after the heat source has been discontinued. However, it can take many months for the skin to go back to normal.

      • Thank you ever so much for your reply. Your reply gave me hope that my leg might improve. To give you an update, I think it has got smaller and lighter since I last wrote to you. It started of being pretty much the width of my thigh, but it has started to fade around the edges, so it is more in the middle/of the top of my leg now and more pink than purple. If it is of any interest to you, I can try to take to photo of it, but I image you have seen this plenty of times before! Thanks again for your help.

  3. I’m sooo GLAD I came across this blog. I have been experiencing this problem for the past couple years since pain from both MS & back pain have worsened. Many nights, I would use a heating pad on my back, stomache, or legs for a couple hours. The next morning, I would have the EXACT SAME “veiny/rash” appearance as depicted in the photo above. Also, just as the initial poster, it produced no symptoms other than being incredibly embarrassing–especially during the summer months.
    Moreover, I’ve noticed that it no longer takes a heating pad to produce this appearance. As of late, it will sometimes develop on both my arms, legs, stomach, hips, back, and chest…..even during the winter months. Is my skin now permenately damaged???

    • Thanks for the question, Chera. I can’t say specifically for you, but the condition usually resolves after the heat source has been discontinued. However, it can take many months for the skin to return to normal. You should contact your doctor.

  4. Can this maybe also be caused by electric blanket use over night?

    I fell asleep the other night and forgot to turnt the blanket off. I woke up with the lower half of my back looking like that.

  5. I get that! Just googled “skin patchy sit near fire” and got this. Is it dangerous? I always sit by the fire for ages . Got it all down my arm and on my thigh.

    • lewis-Thanks for the question. Mostly, just unsightly. There is some evidence that toasted skin syndrome might increase risk for skin cancers. Doctors always advise to change your behavior to get away from the heat source and have your skin examined if there are any concerns.

  6. i bought some new clothes recently and i didn’t wash them and for the past three days i have been getting reddish welt or hives on my skin i have also started using a different detergent is it possible that i’m allergic to it

    • Janie, I couldn’t say without seeing you. Skin allergies to detergents are uncommon. I recommend that you see a physician so that you can get help with the diagnosis.

  7. Thank you! I have this- I hate being cold and I bought a presto heat dish. I figured that it was related to the dish because it was only on that side. I really hope it fades.

  8. Mine was from a space heater! My doctor recommended putting Retin A on my legs every night and it has faded it almost gone in 3 months

  9. Can this happen after just 1 long exposer to a heating pad? I have had a bad pain in my hip and fell asleep last night on my heating pad. Today I noticed a red map-like (spider-web like) area on my hip today. L

  10. Hi, I’m very glad I came across this blog! Someone I know has been doing this for quite a while…. she lays on a heating pad any time she can… Always on one side more than the other. Now, she has this really bad burn on her side, and it looks to be getting worse. She doesn’t believe me about the burn and won’t stop laying on it.. If she continues to lay on the heating pad, is there any other danger than the permanent discoloration that I can tell her about?

  11. I have sat next to a space heater for about two ear almost every day straight. Noticed te rash and am freaking out. How likely are u to get skin cancer from a situation like this??

    • Mindy, it is purported, but rare. If you have concerns or have any suspicious marks or rashes on your skin, then see your dermatologist. It will allay your concerns. Best to you.

  12. I AM SO THANKFUL to have come across this blog! I believe (without seeing my derm to confirm, my appointment is in June) that I have TSS. I have been using a space heater at my work daily since October 2013 (and every winter for years) and I notice it beginning in November- and just on my legs, knee’s down, no place else, which makes sense why its caused by the heater. It’s spidery, looks like tiny broken blood vessels under my skin, and I have a couple of small red spots (those concern me since the exposure time has been long). I never developed it before I had my daughter in May of 2012 so could it be possible the pregnancy escalated it? I am anxious about my derm appointment, it’s for a full in depth skin screening-

    • Try not to be anxious about your upcoming derm appt. You’re being smart and proactive by getting a full-body screening. I’m sure your doc will be able to help with the diagnosis as well. Thanks for commenting.

  13. wow!! Amazing. Now I understand why my left upper leg looks like that. (my laptop heats on the left side) The pattern becomes more visible when I shower with hot water or take sun. Is the heat! I am olived-skinned and it is not so apparent. but still I am happy to find an explanation!

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