The pain that Lyme can cause: Erythromelalgia, or "Man-On-Fire Syndrome"

I have recently been diagnosed with erythromelalgia (aka EM), a painful neurovascular disorder that is believed to be rare....in fact, Kate Conklin's video above states that fewer than 400 people in the United States have actually been diagnosed with EM.

NORD (National Organization of Rare Disorders) defines defines erythromelalgia thusly:

Erythromelalgia is a rare condition that primarily affects the feet and, less commonly, the hands (extremities). It is characterized by intense, burning pain of affected extremities, severe redness (erythema), and increased skin temperature that may be episodic or almost continuous in nature. (The prefix "erythro-" denotes redness, "mel-" is a combining form meaning limb or limbs, and the suffix "-algia" indicates pain.) Although erythromelalgia typically affects both sides of the body (bilateral), it may sometimes involve only one side (unilateral). In addition, the disease course may be extremely variable from case to case. For example, in some individuals, symptom onset may be gradual (insidious), with the condition potentially remaining relatively mild for years. However, in others, it may have a sudden (acute) onset, possibly spreading and becoming severe over weeks.

The specific underlying cause of erythromelalgia remains unknown. However, the condition is thought to result from vasomotor abnormalities or dysfunction in the normal narrowing (constriction) and widening (dilation) of the diameter (caliber) of certain blood vessels, leading to abnormalities of blood flow to the extremities. Erythromelalgia may be an isolated, primary condition or occur secondary to various underlying disorders. Primary erythromelalgia may appear to occur randomly for unknown reasons (sporadically) or may be familial, suggesting autosomal dominant inheritance.

My symptoms began suddenly, just as Kate's did in the video.  Fortunately my erythromelalgia has not been as severe as hers, but it IS painful!  That first day my toes suddenly swelled up and became hot and red and excruciatingly painful.  The soles of my feet were painful too.  The really odd thing is that my Raynaud's syndrome had been very active just before this, so I had the startling experience of seeing my toes turn from a cold ice blue to a hot beet red in just a few minutes!

EM makes it VERY painful to walk when it's flaring.  EM has also affected my face and ears on occasion, causing them to feel very hot, turn bright red and practically glow, but my feet seem to be the main targets of the erythromelalgia.....they are nearly always red and painful these days.

I suspect that EM is not as rare as most doctors believe; there are likely MANY people have EM who remain undiagnosed.  I myself recently encountered two people online who apparently have undiagnosed erythromelalgia....they reported their symptoms to me and when I told them of erythromelalgia and they looked it up online, they were able to confirm from the descriptions and pictures that's exactly what they do have! Of course, the reason they didn't know they had erythromelalgia in the first place is because their doctors had never heard of it.

So you've read this far and are now wondering, "what does erythromelalgia have to do with Lyme?"

When I first started to research EM, I found information that indicated in many cases there is no known cause.  Erythromelalgia can be primary, that is a disease in and of itself, or it can be secondary to another illness or syndrome.  One of the illnesses associated with EM in the literature is SLE (systemic lupus erythematosus), or lupus for short.

In my case, I think Lyme has everything to do with my erythromelalgia!  After all, I blame Lyme for triggering my lupus anyway (see my previous post on lupus). I know that I was born with a familial predisposition to developing lupus, but I didn't actually develop the disease until AFTER I contracted Lyme.

Since EM can be secondary to lupus, and Lyme often mimics or triggers lupus, Lyme has very probably triggered the EM (directly or indirectly) in many of those poor souls out there who have it.

And I found at least one Lymie who agrees with me, Kris who writes the Lyme blog called Lyme Lights Utah.  She too suffers from erythromelalgia and has numerous posts on this topic on her blog.  I confess I have not read them all...yet. Please see her very well written and interesting initial post on erythromelalgia from November 2009.

Of course, since I'm a scientist, I've continued to dig into this topic.  I have actually come up with another reason for believing that Lyme and erythromelalgia are linked somehow, based on data in a recent medical paper I read: Incidence of Erythromelalgia: A Population-Based Study in Olmstead County, Minnesota.

The authors of this article have discovered that the incidence rate of EM is increasing over time.  So erythromelalgia is becoming more and more common every year in Olmstead County, MN.

Guess what else is becoming more common every year in Minnesota?  Yep!!  Lyme!

I decided to compare the data for EM from the paper with the data on the Minnesota State website regarding the incidence rate of Lyme disease as a function of time.

From http://www.health.state.mn.us/divs/idepc/diseases/lyme/casesyear.html

The nice graph above is from the state website.  The medical paper put all of the EM numbers into 3 data "bins" that were each 10 years wide (1976-85, 1986-95, 1995-05).  I used these bins to make the following graph of incidence of erythromelalgia as a function of time:

In order to actually compare the incidence of Lyme properly to the incidence of EM in Olmstead County, I need the Lyme numbers from Olmstead County only.  But those data were unavailable on the state website, so I used the Lyme numbers for Minnesota as a whole for comparison. 

I summed up the numbers in each "bin" to calculate the 10 year incidence rate; unfortunately, since Lyme came to national attention in the late '70s in Connecticut, the numbers for Lyme disease in Minnesota began in 1986, at least on that particular website.  So I was only able to calculate numbers for two of the bins: '86-'95 and '96-'05.  Statistically this is not "good enough" to prove anything, of course.

The results are interesting nonetheless....I ended up scaling the Minnesota Lyme numbers by dividing them by 200, and then was amazed at how similar the two graphs looked, at least from 1986 - 2005!

 

So the scaled (divided by 200) Minnesota Lyme numbers (red bars) look very much like the Olmstead County erythromelalgia numbers (blue bars)....even though this does not suffice to prove anything, it is suggestive.  It is enough, at least in my mind, for doctors to tell patients who present with EM that they ought to be tested for Lyme.