Is a general intolerance to heat normal for EM?

Hi, so I am just wondering, does everyone or at least some people with EM just have an overall general intolerance to heat? I get flares in my hands and my feet with heat, but even about six months before they began to develop I just started becoming more generally intolerant to heat. I am only 23 and began developing EM about 18 months ago. I used to be an athlete, spent a lot of time training, running, in the gym etc, and outside of training I would spend a lot of my time in steam rooms and saunas stretching, without any trouble whatsoever. But since developing EM, I have just become so intolerant to heat, any sort of heat or light exercise makes me really uncomfortable and itchy, yes my hands and feet flare, but the rest of my body just feels like its overheating and again is itchy and uncomfortable.

Is this normal with EM? Or could it be something else? I have so far tries aspirin and antihistamines, with little effect. Magnesium seems to help.

Hi Anthony,

Heat intolerance is a hallmark symptom of EM, one that I personally experienced with my flares.

Do you mind describing the sensation of your heat intolerance? As I said I began to develop this intolerance before I began to get flares, or have flares frequently. They began to develop when I was studying in Barcelona last year, I had no idea what was happening. As I said, I had been someone who would run 10 miles on a hot day, get on the racing bike in my living room with the heating up to max for a few hours and then have a boiling shower with no issues. But now its like any sort of activity (apart from swimming) just feels intolerable.

If I was outside on a warm day I would initially feel a light tingling sensation in my right big toe. This was the precursor to the flare, if I can could get inside in a cool area and elevate, I can keep the flare at bay, if not, then it’ll progress to erythema, swelling etc… Upon removing my socks, I’d see tiny sweat droplets on the area that was tingling. There was trauma to this area in the past, initially due to an ingrown toenail and it’s eventual removal. (multiple times)

Considering most of our situations are unique, I describe my right toe further in this thread: My Steady Improvement

As far as athletic training goes, about 6 years ago I was in peak physical shape. I worked out 6 days a week (weights, high interval training etc…), never even heard of EM. Then I got a job in NYC, no longer had time for hobbies and eventually EM surfaced. If I recall correctly, carter and joeshoe were big into training before their EM started, just a trend I noticed.

It’s possible what you’re calling a “general heat intolerance” is just stress induced paresthesia. The stress response heightens senses and stimulates the body, especially the nervous system

Case in point: A few weeks after I first began presenting EM symptoms with flaring at my knees, I started to think something was wrong with my hip. I even began to ice my hip. It turned out my hip was fine. It was just anxiety and stress.

Hi Anthony,
I have had the same response to heat as you. Mainly if I am in an air conditioned room then spend time outside, prior to flare in my feet or hands I have an odd sensation in my legs and arms that are exposed to the sun, like something is crawling on me. I feel it may be just the blood vessel response to different temperature? I was able to spend some time outside about 2 weeks ago pulling weeds out of the garden and while I was actually sweating I didn’t flare bad but when I came into my air conditioned house my legs started to have an extreme burning sensation but they were not red or hot like an EM flare. I had to lay in front of a fan for awhile until it subsided. About 1 1/2 years prior to EM symptoms I just couldn’t handle being out in the sun as I used to and occasionally I would feel like my body was trembling from the inside and thought I might pass out. Related or not, I am unsure as I have never ask another in regards to it. Thanks for bringing this up!

Hi, Anthony. Retired tri-athlete, here. My heat intolerance has gotten lots worse. I live in the South, where it’s very warm and humid. This past weekend, I went out of town with my husband. We had a brief walk from the hotel to its restaurant, and by the time I got there I was drenched in sweat. Crazy drenched–sweat rolling down my face, and my clothes were completely soaking wet. Besides being embarrassing, it was pretty uncomfortable for the rest of the afternoon, until I was able to go back to the room to change clothes. So…for me? Yeah. I’ve become much more affected by the heat. I spend as much time in the pool as I am able–it’s the only place I seem to feel like myself, anymore. Good luck with all of this!

This is a multi-faceted question and nearly everyone here will say “yes” but their reasons for saying so will likely vary. EM is an intricate symptom complex, not necessarily a disease, so while people may have a similar end symptom of being intolerant to heat, it likely stems from different reasons for each individual. This is why EM is so hard to treat. For some it is a nervous system issue like @CarterDK is stating and is why he responds so well to a sodium channel blocker that helps dampen erratic sympathetic flow. For others it can be due to hyperemia from a various number of causes. Basically poor bloodflow or the inability to sweat properly causes blood to rush to the affected areas when exercising or in hot weather. Or it could be a combination of everything.

In short, yes. It is a defining symptom of EM but can result from many dysfunctions which is why we’re all here. If magnesium seems to help, you might want to keep taking that and try to not let your feet get too cold. Magnesium is a natural calcium channel blocker that dilates blood vessels. So if that helps, you could have vasospasms that are restricting bloodflow which causes the hyperemia when you’re hot or exercising. There are a lot of people on here who take magnesium with great results. Follow the breadcrumbs and keep trying things, it might take a combination of a few things to really notice improvement.


Hey Anthony,

What I deal with sounds almost identical to your experience. Starts with tingling/numbness in the tip of a toe or finger and then turns into a full on flare within a day. I do not have a diagnosis of EM but my experiences seem to fit the descriptions. I really think that stress and heat are big triggers for me. Been going on 6 years now. Within the last 3 months I have been taking daily vitamin D, B12 and drinking 8-10 glasses of water a day. Also cut out milk and most processed food from my diet. I’ve only had minimal flare episodes in the last month which is great for me. When it does happen I get the tingling but then it goes away after a day. No flare. I‘m also trying to do kind of meditative breathing techniques throughout the day whenever I feel stressed or anxious. This all seems to be helping me. I’m certainly not a doctor but my primary did recommend the supplements in addition to magnesium. Not sure if there’s any real reasoning behind any of this and maybe it’s just psychological but it seems to be helping and that’s good enough for me. Forgot to mention that I’m 41 in decent shape. I used to run trail ultramarathons but running became super uncomfortable with the constant flares in my feet. Now I am primarily surfing and mountain biking. Those activities are tolerable.
Good luck to you!

Hi Guys! Wow, thank you for all the replies, I had not expected so much, it seems that we all experience something slightly different, it may be just the nature of EM, especially if its secondary EM. Again, I would just like to make clear of what I am trying to describe as “heat intolerance”. It seems that my body cannot regulate temperature when it comes to heat (almost like cold blooded, a weird description but yeah), this began to develop before I started having major flares in my hands and more recently my feet, when I was in a good period of my life, I just didnt really understand what was happening and it started gradually and I just sort of ignored it. So now I get flares, but again in the heat (today for example I walked home from the swimming pool on a warm sunny day) and I just feel uncomfortable and itchy, I don’t feel I am sweating too much or too little, but its just really uncomfortable. I noticed it a lot when I returned to the gym this time last year, as soon as I did some spinning I would get itchy and clamby all over (as well as flares in my hands). I tolerate the cold well enough, I do get a bit of raynauds (which has got a bit worse since developing EM) but I can surf, in Ireland, in the atlantic, during winter, with no issues whatsoever. It is actually an activity that is great for those with EM.

As mentioned, swimming is the only real exercise I can do now, its great that I can still stay someway fit (far from what I used to be), but I do tend to have more flares throughout the day afterwards.

As I mentioned earlier, I am working with a dermatologist, but currently on roaccutane so she does not want to try any new medications until we are finished. Tomorrow I have an appointment with my doctor (I have never spoken to him about my EM or related issues). I will talk to him about it and get a second opinion, I am also going to see if he thinks anything else might be influencing my heat intolerance (thyroid issues etc). I will keep you guys all informed, we all have to be proactice!

Anecdotally, many people have developed flushing/burning while on accutane.

I looked into this a lot as to the “why”. I never took accutane but thought a similar mechanism could apply to my case.

Couldn’t find any explanation as to “why” by my derms or online, but derms acknowledge it can cause vasodilation

There are some people with accutane-induced flushing/burning that have gotten relief from plaquenil or SSRI’s.

This might not even apply to your case but thought it was worth mentioning. Cymbalta helps me the most with heat tolerance, although not completely. An allergist/immunologist might help rule out MCAS (itch). On the 4th yr, my face/scalp started to itch, and my derm thinks it is due to a connective tissue disease (dermatomyositis).

good luck

For me it has gotten much better. For a long time I could not tolerate heat. It was oppressive. When outdoors in heat it felt as if the air was pushing on me. I had other associated symptoms, including the reduction of sweating. For some reason, I would not sweat. One of the people on this thread is right. I have found EM to be a systems issue. Two things have helped. First, gut health. I have given up dairy-that helped. I have given up veggies that cause digestive distress --those with high value in lectins. I follow the Grain Free diet developed by Dr. Gundry. Second is acupuncture. Specifically, using a method created by a famous Neurosurgeon named of Dr. Jiao Shun Fa. His is widely acclaimed for his work both in Neurosurgery and his work in Traditional Chinese Medicine. If you can find an acupuncturist who has studied and uses his methodology, I would recommend. I believe his cranial acupuncture treatment and a healthier gut has helped me eliminate most all of my EM symptoms. The one exception is redness and occasional swelling in my toes. But no pain, my body sweats again, etc. etc. Wishing the best for you.

Thanks for the information, but I have honestly noticed no difference whilst on accutane (apart from my skin been a bit drier and susceptible to sunburn) but my flushing precedes accutane by at least a year.

interesting… hope you get some answers and let us know

Hi, yes I also suffer from heat intolerance. Mine started about 10/12 yrs ago with a burning sensation on the soles of my feet and the tops of my toes. I only had it at night and my feet were fine during the day. I also get a prickling sensation on my back when its sunny and warm. I also get flushing on my face. I asked my Dr what it was and he just shrugged his shoulders and said he had no idea so I just carried on working and like I said my feet were only like that at night and just used to use a big fan. Then just after lockdown it really started with swollen feet and ankles which then went bright red and I have an intense itching which drives me insane as it feels like insects are crawling all over my feet and legs and the more you scratch it, the worst it gets. The redness has now gone up my legs to just below my knees and the itching continues. I use an itch cream from amazon which helps. I also soak my feet in cool water for about 45 min with Epsom salts which helps a lot and takes some of the redness out. I am 66 and assumed this was an older persons condition but since found out its people of all ages who have it, even children. It breaks my heart to think younger ones are suffering too of this horrible condition, as you are, at only 22. I hope they find a cure for this. I wish you all the best.