79-year-old woman with blue toes

The Solitary Blue Toe: A Unique Presentation of Antiphospholipid Syndrome

Antiphospholipid syndrome is an autoimmune disease characterized by vascular thrombosis involving both the arterial and venous systems that can lead to tissue ischemia or end-organ damage. Much of the literature describes various symptoms at initial presentation, but isolated tissue ischemia manifesting as a solitary blue toe is unusual. We discuss a case of a 23-year-old man who presented to the emergency department with a solitary blue fourth digit with minimal erythema and edema, who was suffering from exquisite pain. Following an extensive workup, the patient was diagnosed with antiphospholipid syndrome with thrombi of the vasculature in their lower extremity. With therapeutic anticoagulation, the patient's symptoms subsided and amputation of the digit was prevented.

The purple digit: an algorithmic approach to diagnosis

The acute onset of purple digits is a concerning manifestation and may represent underlying, potentially life-threatening disease. Correctly identifying the etiology of purple digits is essential to proper management, and can aid in the diagnosis of systemic disease. Multiple causes of purple digits and significant overlap in clinical presentation can make diagnosis difficult. Despite the various causes of acute purple digits in the published literature, an algorithmic approach to the evaluation and management of the most common and alarming etiologies has yet to be established. The initial step in evaluating a patient with purple digits is to determine if the cause is associated with hypoxemia or trauma. If the patient is in a stable condition, the dermatologist needs to determine if the process could be related to cold exposure such as Raynaud phenomenon, acrocyanosis, pernio, cryoglobulinemia or frostbite. If the disease occurs independent of temperature, physical examination and histological evaluation of the skin is recommended. The lack of peripheral pulses are concerning for acute arterial thrombosis from peripheral vascular disease or arterial embolism. Non-blanching skin changes on the digit that lack inflammation and microthrombosis most likely represent a bleeding or platelet abnormality; however, if microthrombi are identified a more life-threatening processes such as purpura fulminans or embolic phenomenon may be occurring. Evidence of blood vessel inflammation suggests a leukocytoclastic vasculitis. The patient with a purple blanching digit and normal pulses requires an extensive historical review to help determine the cause. This review presents an algorithmic approach to assist in the evaluation and management of the purple digit.

A vitamin K antagonist rapidly reverses a blue toe syndrome in a patient with lupus anticoagulant and antiprothrombin antibodies

A 30-year old male was admitted to the hospital with extremely painful blueish discoloration of his toes. After clinical and laboratory evaluation the diagnosis of a blue toe syndrome due to primary antiphospholipid syndrome (APS) was made. Complete resolution of the blue toe syndrome occurred within 72 hours following 9 mg phenprocoumon. APS consists of the association of lupus anticoagulant or antiphospholipid antibodies with arterial or venous thrombosis, thrombocytopenia, and spontaneous abortion. The exact pathways leading to thrombosis are still unknown. Our group has previously proposed that membrane-associated immune complexes contribute towards clinical symptoms in the antiphospholipid syndrome. The case presented strengthens that concept.