Em is a syndrome. That is it's a set of symptoms. If you have EM you have a situation usually where the extremeties usually the hands and feet show swelling and burning. And it's often in the feet. It may move the the hands as well and may move up from the feet into the lower part of the legs.
The causes are many, but it's a symptom or kind of side effect of an underlying disease that can be treated or is something you're dealing with. That would make it secondary EM. If it's EM. And diabetics, Lupus, Cancer sufferers or others may get EM as a result of their disease, as a side effect of their disease. See Wikipedia for more info on that. It may also be a result of some other problem that happened, but this is a rarely reported thing.
Experts may even disagree on whether you have EM or not. They may take different tests. some may be geared toward nerve conditions that may cause it others may be geared toward changes that might happen in some EM cases where the cells of the feet for example have been changed and show a different kind of cell morphology. Since it's rare it may be difficult to get a consensus from doctors and of course one might not even have it and just imagine having it, but have some other problem or issue.
Some of the more rare things that can cause EM or something like EM that have been listed over time, these are early quotes from much earlier EM research.
From a Fungus infection, or mushroom poisoning.
From a scratch from a cat. . . this is a rare report and may not be verified by medical reports.
From a side effect from various drugs.
From vascular constriction of the small vascular blood vessels, the shunting of blood.
An reaction of the body where it's trying to send blood to a place where it's not needed, in other words the bodies ability to automatically adjust and send more blood to muscles that needs it is somehow damaged and the messaging is sending blood where it doesn't need to go causing swelling, heat and pain.
Tied with and a part of a neuropathy, which seems to be the case with some who have a cycling of chills sharp pains and numbness (more like Neuropathy) mixed with sessions of EM flares.
As a result of drugs, once again I'm mentioning this as some have pointed out side effects. In my mom's horrible EM case, which is severe, she had a mild form of EM it would seem or a precursor to it as a side effect of Xanex, but then when she took Risperdol, the full blown debilitating flares began which basically wiped out our normal household life.
An injury also for some they developed EM when breaking a toe or doing damage to a foot and EM like symptoms would happen on that side. Early on reports on the internet would state that some had it on one side as a result of an injury and it was rare than people had it on both sides. Some theorized that it might start on one side as a result of an injury and then cycle to the other side, which to me seems to be strange, and almost impossible. Those who had it on both sides were not seemingly in the majority from some early reading research back in 2002 that I did, but it seems that now at least what I see and read out on the net. . . I'm not a medical professional so take my advice and thoughts as only representations of what I've heard and is basically comments from a layman. . . at first I read about EM happening mostly to one side or the other. With more research and hearing about it, it seems that the majority of sufferers at least here on this board have it on both sides.
Doctors will likely rule out a bunch of other things. And as you treat EM or it's symptoms other things from your lifestyle changes can cause other problems. So you can if you have a severe form of the syndrome develop other problems from your life adaptation and coping with EM.
It sounds like you're having a minor reaction and you're lucky actually compared to the more severe cases. I'd say be careful and cautious with your approaches and see doctors. This is just my advice as a layman. Don't be to gun ho, to take the most medication and exotic medications that could cause other side effects. In my mom's case she seems to have gotten EM from side effects from drugs or perhaps being taken off drugs. Depending on the theory one wants to belief. In all cases, it seems the consensus from doctors is her nerves are damaged and it can't be cured.
I wouldn't be in to much of a hurry to claim EM or think it's EM. Take your time and let doctors propose different diagnosis and solutions and be aware that with more complications and side effects one may have side effects that seem to be EM or some other rare disease and it might not even be that. EM is not really a disease it's a syndrome or group of symptoms that happens with a common set of symptoms. As it cycles one can claim to have it. For example my hands were almost frostbite and I used them in the cold and my hands swelled up and got red. They seemed to be very EM like and I took a picture of them, kind of panicking one day. But later when it went down I realized it was just a normal reaction to this other stimulus and my EM fears were just something in my mind that day, imaging I came upon proof of family genetic based EM that might be in my genes without a genetic test.