A survey of mepacrine prescribing by dermatologists

apy with glycyrrhizin and pregabalin were started. The pain was remarkably relieved within 1 month and the erythema had reduced, being invisible in the morning (Fig. 2a) and emerging only after a long time standing or in warm conditions (Fig. 2b). The erythema gradually subsided completely over the following 2 months of continued treatment (Fig. 1b). No recurrence has been observed to date. Secondary erythromelalgia is associated with multiple diseases, malignancies, pregnancy and drugs. Oestrogen–progestin replacement therapy has never previously been reported as inducing erythromelalgia. The pathogenesis of erythromelalgia is not entirely clear, resulting in a lack of effective and standard treatments. Class 1B antiarrhythmic drugs such as lidocaine and mexiletine have been reported to relieve the pain in hereditary erythromelalgia, and aspirin is effective in cases secondary to polycythaemia vera or other haematological entities. Other pharmacotherapies such as nonsteroidal antiinflammatory agents, ion channel blockers, antidepressants, anticonvulsants and sodium nitroprusside have also been reported. Chemical or surgical sympathectomy is a nonspecific method to interrupt the nociceptive pain fibres or sympathetic fibres. In this case, the patient improved markedly after the discontinuation of HRT and oral administration of glycyrrhizin and pregabalin for 3 months. Glycyrrhizin is able to relieve pain by acting on the cyclooxygenase/prostaglandin E synthase pathway, and has been used to treat inflammatory diseases. Pregabalin was documented as a combination therapy for erythromelalgia. It binds to the a2-d ligand of voltage-gated calcium channels, which prevents the release of norepinephrine, glutamate and substance P. To date, therapeutic response to the treatment has not been satisfactory and consistent. A multidisciplinary approach is necessary for pain reduction and functional recovery. Although drug-induced erythromelalgia presents a reversible course, gynaecologists and dermatologists should be aware of this underlying adverse effect of HRT. In addition to the discontinuation of the culprit drug, the combined application of glycyrrhizin and pregabalin may be an option for treatment.