Erythromelalgia Unmasking a Triple-Negative Essential Thrombocytosis Phenotype After Recurrent Arterial Thrombosis Misdiagnosed As Peripheral Vascular Disease

Erythromelalgia is characterized by episodic burning pain, erythema, and warmth of the extremities and may occur in association with platelet-mediated microvascular dysfunction in myeloproliferative disorders.Recognition may be delayed when the clinical course is dominated by large-vessel thrombosis and persistent thrombocytosis is attributed to reactive causes.We describe a 46-year-old woman with recurrent arterial thrombosis requiring multiple vascular interventions, persistent thrombocytosis, and progressive disabling limb pain.Initial investigations demonstrated iron deficiency, negative JAK2, CALR, and MPL mutation testing, and bone marrow findings without definitive evidence of a myeloproliferative neoplasm.Longitudinal reassessment identified characteristic erythromelalgia, with recurrent burning pain, erythema, and warmth involving multiple extremities.Recognition of this phenotype prompted reconsideration of an underlying platelet-mediated thrombotic disorder and restructuring of treatment.Antiplatelet therapy, anticoagulation, symptomatic management, and subsequent hydroxyurea treatment were associated with substantial clinical improvement and recovery of functional independence.This case illustrates the importance of recognizing erythromelalgia in patients with recurrent arterial thrombosis and persistent thrombocytosis, particularly when initial hematologic investigations are nondiagnostic.The clinical findings supported a suspected triple-negative essential thrombocytosis phenotype, although definitive myeloproliferative classification remained unestablished.