Blue Toe Syndrome in Behçet's Disease: A Case Report.

BACKGROUND Vascular Behçet's disease (VBD) is a rare but potentially life-threatening subtype of Behçet's disease that is characterized by multisystemic vasculitis. It primarily affects males with ancestry traced back to regions along the ancient Silk Road. Both arteries and veins, regardless of size, may exhibit complications, including aneurysmal degeneration or occlusion. While venous involvement is observed in two-thirds of VBD cases, arterial complications are notably the most severe and lethal. Arterial aneurysmal degeneration is more common than occlusive complications, with larger arteries being predominantly affected in VBD. Data regarding isolated small-vessel arterial occlusive disease in VBD are limited. Given the rarity of this presentation in this patient population, it becomes mandatory to thoroughly evaluate such patients to differentiate small-vessel vasculitis from other similar diseases, such as Raynaud's phenomenon, which has a different etiology and management and generally has a more benign course. Here, we delineate the concept of isolated small-vessel vasculitis as a cause of blue toe syndrome in patients with VBD. CASE REPORT This report describes a distinctive case of vascular Behçet's disease in a 51-year-old man who initially exhibited unilateral blue toe syndrome, which swiftly progressed to dry gangrene of the toes. Despite reports of large-vessel involvement, there is a paucity of data on isolated small-vessel vasculitis-induced digital ischemia in VBD. CONCLUSIONS This atypical case underscores the necessity of clinical discernment in differentiating inflammatory microvascular occlusive disease from vasospastic Raynaud's syndrome, both of which can complicate Behçet's disease.