A Study in Erythromelalgia

Summary Erythromelalgia is a condition characterized by redness and burning pains in the limbs occurring as a response to a rise of limb temperature. In the past, it has been treated by a number of drugs, none of which has been particularly effective. In this study, an electric blanket was used to produce a rise of limb temperature and development of pain in a 25 year old man who had been disabled by primary erythromelalgia. 10 drugs of known vaso‐active or anti‐inflammatory properties were tested by this method without affecting the pain experienced by the patient. Despite these findings, a pilot clinical study suggested that when used in combination, methysergide 2 mg t.d.s. and ephedrine 60 mg t.d.s. could prevent the occurrence of the patient's symptoms. However, owing to the known toxicity of methysergide, a test was sought which could demonstrate an objective effect of this agent before continuing its use in combination. Further testing with an electric blanket did not confirm its efficacy, but testing with a bicycle ergometer did demonstrate therapeutic benefit of both methysergide and its combination with ephedrine. After nine months successful use of the methysergide and ephedrine combination, it was found that methysergide could be deleted with minimal aggravation of the condition. A review of the clinical features of erythromelalgia suggests that this phenomenon may be due to kinins liberated by a rise of limb temperature in predisposed subjects.