erythromelalgia ( em ) is a rare disease characterized by painful swelling and erythema on the extremities [ 1 , 2 , 3 ] .
the symptoms are often triggered by minor trauma , exercise , increased skin temperature , or heat exposure and often alleviated by cooling and elevation of the involved extremity .
there are three distinct types : primary em , secondary em and em with thrombocythemia .
primary em is observed most commonly in patients aged less than 30 years without underlying disorders .
secondary em is associated with several autoimmune disorders [ e.g. systemic lupus erythematosus ( sle ) , insulin - dependent diabetes mellitus ] .
in contrast , em with thrombocythemia is usually treated with aspirin , since the burning pain is relatively easy to control . in this report
, we describe a case of adult - onset em successfully controlled with steroid pulse and pregabalin .
a 68-year - old japanese woman presented at our outpatient clinic with a 10-year history of painful , recurrent erythema on her bilateral hands . there was no erythema on her feet .
she had been diagnosed with idiopathic em and treated with oral intake of vitamin e 150 mg / day , transamin capsules 750 mg / day , prostaglandin e1 15 g / day and aspirin 100 mg / day , without any improvement . on her initial visit , physical examination revealed dark erythematous swelling on her bilateral hands ( fig .
the biochemical profile revealed normal levels of antinuclear antibodies ( 40 ) and a slightly decreased igg level ( 702 mg / dl ) .
no specific autoantibodies ( e.g. dsdna , ssdna , ss - a , ss - b ) were detected .
prothrombin time , activated partial thromboplastin time , serum fibrinogen , and platelet count were within normal ranges .
the patient was found to be euthyroid by a measurement of the basal tsh and free t4 levels as well as by trh provocative test .
internal malignancy was excluded at the internal department . from the above findings , we diagnosed the patient as having adult - onset em of unknown origin .
we administered methylprednisolone sodium succinate 1,000 mg / day intravenously for 3 days , and after that we treated her with oral prednisolone 60 , 40 and 20 mg / day for 2 days each .
two days after the administration of methylprednisolone sodium succinate , eruption and pain had improved ( fig . 1b ) .
the visual analog scale ( vas ) score improved from 10 to 2 ( fig .
however , 6 days after therapy start , her pain gradually developed again ( vas score 2 to 5 ) .
the vas score improved again , and the patient has been able to control her pain for half a year , although slight erythema could still be observed .
em is a rare condition characterized by episodic bouts of burning pain , erythema , and edema , most commonly involving the extremities .
symptoms are often triggered by minor trauma , exercise , or heat exposure and often alleviated by cooling and elevation of the involved extremity .
several reports have suggested successful treatments for em [ 2 , 3 , 4 , 5 ] , but the optimal therapy is still under discussion . in this report
, we describe a case of adult - onset em successfully controlled with steroid pulse and pregabalin as evaluated by vas .
previous reports suggested an association between secondary forms of em and autoimmune disorders [ 3 , 6 , 7 ] .
indeed , there is evidence that secondary em might be associated with an autoimmune condition in which there are autoantibodies directed against the sodium channel encoded for by the scn9a gene .
in addition , jackson and oates   reported a case of autoimmune - related em ; however , these autoantibodies were not suggested to be directly associated with em like sle . on the contrary , the primary form of em
is associated with a mutation in the sodium channel nav1.7 , which is selectively expressed within the dorsal root ganglion and sympathetic ganglia and encoded by the scn9a gene [ 3 , 8 ] .
once diagnosis is established , potential secondary causes must be excluded [ 6 , 9 ] .
other causes associated with em include sle , raynaud 's disease , pernicious anemia , thrombotic thrombocytopenic purpura , infectious mononucleosis , metabolic , endocrine , and vascular origin and diabetic neuropathy [ 6 , 7 , 9 ] .
although there was no evidence for autoimmune - associated em in our present case , late onset of em might indicate the possible involvement of autoantibodies .
in addition , suh et al .   reported that adult - onset idiopathic em could be successfully treated with corticosteroids and pentazocine . furthermore , pfund et al .  
for the above reasons , we decided to administer steroid pulse and pregabalin , and monitored the patient 's pain with vas .
vas is a simple assessment tool consisting of a 10-cm line with 0 on one end , representing no pain , and 10 on the other end , representing the worst pain ever experienced , which a patient marks to indicate the severity of his or her pain ( fig .
, the vas score and erythema on the hands immediately improved after administration of high - dose methylprednisolone sodium succinate and were maintained by oral pregabalin .
although we describe a single case and the observation is limited , our case might suggest a possible , optimal therapy for adult - onset em .
 adult - onset erythromelalgia ( em ) is a rare disease characterized by episodic bouts of burning pain and erythema for which the optimal therapy is unclear . in this report 
 , we describe a 68-year - old japanese woman with adult - onset em . 
 intravenous administration of methylprednisolone sodium succinate 1,000 mg / day dramatically improved her pain as evaluated by the visual analog scale . 
 although the patient 's pain gradually developed again , it could be controlled with pregabalin . 
 our present case might suggest a possible , optimal therapy for adult - onset em . 
Introduction
Case Report
Discussion