Skin perfusion in patients with erythromelalgia

Background Erythromelalgia (EM) is a chronic disorder characterized by inte rmittent pain, warmth and erythema of the extremities. Symptoms can be prec ipitated by increasing the temperature of the affected limb and can be part ially relieved by direct cooling. Materials and methods Microvascular assessment was conducted under 'hot' (2 8 degrees C) environmental conditions in 61 BM (EMI) patients and 30 contro l subjects. Twenty patients with many of the symptoms of EM were enrolled a s an active control group (EMII). Using laser Doppler flowmetry, basal skin erythrocyte flux (SkEF) and the hyperaemic response to local heating (44 d egrees C) were measured. Results Compared with control subjects, basal SkEF was reduced at the toe ( P < 0.001), index finger (P < 0.05), dorsal and plantar aspects of the foot (P < 0.01) in both patient groups and at the medial mid-calf (P < 0.05) in EMI patients. Both EM groups also had a significantly reduced maximum SkEF at the dorsum of foot and medial mid-calf (all P < 0.001) compared with co ntrol values. In a subset of patients and control subjects, transcutaneous carbon dioxide levels were raised in EMI patients (P < 0.02)compared with l evels in control subjects. Toe temperature was significantly reduced in bot h EM groups compared with control subjects (both P < 0.001). Conclusion Our study indicates for the first time that there is a vasoconst rictor tendency in patients with EM, which may be related to functional or structural changes in skin microvessels. Thus, the previous hypothesis that the pathophysiology of EM relates to vasodilatation is not supported in ou r patients. We believe that, in EM, vasoconstriction precedes reactive hype raemia, similar to that seen in Raynaud's phenomenon.