Intravenous immunoglobulin therapy in erythromelalgia management: a case report.

A 49-year-old woman presented with a 16-year history of burning pain, warmth, redness, and edema in both toes, feet, legs and calves. Despite extensive medical testing, including genetic analysis, no specific cause was identified. Initial treatments failed to improve symptoms, leading to impaired quality of life and mental health. Eventually, a six-month course of intravenous immunoglobulin therapy provided complete relief, allowing the patient to resume normal activities. Erythromelalgia is a rare neurovascular condition characterized by pain, warmth, and erythema in the extremities. It can manifest as primary, inherited or sporadic, or secondary to underlying conditions, such as hematological neoplasms. Although genetic studies suggest a pivotal role of a gain-of-function mutation in the Nav1.7 voltage-gated sodium channel in familial cases, the pathogenesis underlying sporadic adult-onset cases remains uncertain. The frequent coexistence of autoimmune connective tissue diseases and the expanding evidence supporting immunotherapies in idiopathic small-fiber neuropathies underscores the possible involvement of adaptive immunity in such conditions. Given the potential complications in untreated patients, risks associated with long-term opioid therapy, and the absence of disease-modifying strategies, intravenous immunoglobulins may offer a more effective approach to pain control than conventional pain relievers, representing a promising direction for understanding the pathogenesis of erythromelalgia.