Background and design: Twenty-one patients with histologically proven Sneddon's syndrome were followed up in a retrospective study. We report on their detailed clinical courses and extensive follow-up examinations.
Results: Incidence is estimated at four cases per million population per year. Nonspecific prodromal symptoms (headache, dizziness) frequently (80%) precede livedo racemosa for 3.5 and (multi)focal neurological symptoms of fully developed disease for 9 years followed by progressive cognitive impairment (60%) 10 years later. Involvement of fundi, peripheral nerves, heart, and kidneys is frequent (50% to 70%) yet usually asymptomatic. Some symptoms prove irreversible (livedo racemosa, multifocal cerebral lesions on imaging, or creatinine clearance), whereas other symptoms tend to resolve after days to years (many focal neurological symptoms, some electrocardiographic changes, or hypertension). Mortality is calculated at 9.5% within an average observation time of 6.2 years. Laboratory findings, including antiphospholipid antibodies, are normal except for elevated erythrocyte sedimentation rates and complement consumption at times of disease progression and increased cholesterol levels parallel to disease extent. Skin biopsy specimens reveal inflammatory findings ("endothelitis") of small- to medium-sized arteries followed by subendothelial proliferation and fibrosis. Hypertension is the only risk factor significantly associated with a more severe course of the disease; no medication proved effective.
Conclusions: Sneddon's syndrome is an often unrecognized, slowly progressive, systemic disease with evidence of vasculitic origin.