Antiphospholipid Antibody Syndrome Ulcers
Antiphospholipid antibodies (APLAs) constitute a large family of autoantibodies, including lupus anticoagulants and anticardiolipin antibodies. These antibodies may occur in several clinical contexts. First, APLAs are present in 2% to 5% of healthy blood donors, and their prevalence is increased dramatically in the elderly. Second, APLAs are common in persons with autoimmune disorders; for example, they are found in as many as 60% of patients with systemic lupus erythematosus. Third, APLAs may develop in persons exposed to medications such as procainamide, quinidine, and chlorpromazine. Fourth, APLAs are found frequently in patients with HIV infection or in patients with congenital immunodeficiency syndromes. APLAs may also be present transiently in as many as 30% of children following common viral infections. Several studies have suggested a genetic predisposition to the development of these antibodies.
An association of APLAs with thrombosis and recurrent fetal loss is well supported. In patients with APLAs, thrombosis can be either venous or arterial; the former type is slightly more common. Venous thrombi usually develop in high-risk contexts, such as during pregnancy, after surgery, or in association with prolonged immobilization. Arterial thrombi may involve any central or peripheral vessel. APLAs have been associated with a number of cutaneous disorders including livido reticularis, livido vasculitis, cutaneous necrosis, infarctions and ulceration, subungual splinter hemorrhages, and vasculitis (palpable purpura).
Differential Diagnosis: Antiphospholipid antibody syndrome can be distinguished from cutaneous anthrax in the following manner.
|*Symptoms occur in appropriate clinical context (elderly, patients with autoimmune disorders, exposure to procainamide, quinidine, and chlorpromazine)
* Patients may have other manifestations including arterial or venous thrombosis
*Ulcers are painful
* Laboratory evidence reveals prolonged prothrombin time
|* Ulcer is painless
*Ulcer and eschar surrounded by characteristic non-pitting edema
*There is no evidence of other thrombotic conditions
Used with Permission from W.B. Saunders
Color Atlas of Dermatology
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