I would like to offer some comments on the excellent article by Sandroni and Davis1 on topical transdermal amitriptyline and ketamine for severe erythromelalgia. From my own work with patients with erythromelalgia and as an erythromelalgia patient myself for the better part of 10 years, I am not surprised by the wide variation in response (0%-95% improvement) reported by the authors' 5 patients. Marked interindividual variation in therapeutic response occurs in patients with erythromelalgia.
Cohen JS. Transdermal Therapy for Erythromelalgia. Arch Dermatol. 2006;142(11):1508-1518. doi:10.1001/archderm.142.11.1508-b