Primary erythromelalgia in a child responding to intravenous lidocaine and oral mexiletine treatment

Abstract

Erythromelalgia is a rare, chronic, debilitating condition characterized by redness, warmth, and severe burning pain of the distal extremities. The feet are more commonly affected than the hands. Pain is precipitated by increases in temperature and by exercise. Patients often obtain relief by immersing the affected extremity in cold water. The pain is often refractory to treatment. For many patients, multiple pain medications have been useless in achieving complete relief of pain symptoms. Previous reports of erythromelalgia among adolescents indicated prolonged relief of pain with sodium nitroprusside infusions, epidural infusions of local anesthetics, or gabapentin treatment. We present a case of an 11-year-old, white, male child with primary erythromelalgia, whose initial symptoms started in his preschool years and whose childhood was marked by escalating episodes of pain with warmth and redness of his feet, precipitated especially by increases in temperature and by activity. All conventional pain management techniques had failed to relieve our patient of his symptoms, and he obtained some relief only by soaking his affected extremities in ice water. He had experienced minimal benefit from seeing a pain psychologist, who helped him develop techniques to cope with the pain. At the time of presentation, the patient's episodes of pain had increased to 15 to 20 per day, and there was evidence of chronic immersion injury to the skin of his feet. Before his most recent hospitalization, the pain had spread to involve his hands as well. The patient was overwhelmed with anxiety and could not participate in school or social activities at the time of admission. During his current hospitalization, he did show some therapeutic response to sodium nitroprusside infusion, which unfortunately had to be discontinued because of side effects and because his family desired to leave the ICU environment, which was stressful to the patient. He also had some response to lumbar epidural infusion of local anesthetics, which could not be continued because he found the motor blockade that accompanied his analgesia intolerable. However, intravenous lidocaine infusion, with subsequent transition to oral mexiletine therapy, proved very effective in reducing the frequency and severity of the pain episodes. The patient was discharged from the hospital with oral mexiletine therapy and has been monitored at the pain management clinic. He returned to and completed school, attended summer camp, and enjoys an active happy life. He walks without precipitating pain in his feet and sleeps 9 to 10 hours every night. He has needed to soak his feet on only 4 occasions in the 6 months since his discharge from the hospital. His quality of life has improved significantly. He has shown no evidence of liver toxicity, and his mexiletine levels have been stable.