The mystery of antiphospholipid antibodies in Sneddon's syndrome

Cutaneous Vasculitis Update: Neutrophilic Muscular Vessel and Eosinophilic, Granulomatous, and Lymphocytic Vasculitis Syndromes

Most biopsies of cutaneous vasculitis will exhibit a small vessel neutrophilic vasculitis [leukocytoclastic vasculitis (LCV)] that is associated with immune complexes on direct immunofluorescence examination or, less commonly, antineutrophilic cytoplasmic antibodies (ANCA) by indirect immunofluorescence testing. Is in uncommon for skin biopsy to reveal solely a neutrophilic arteritis signifying the presence of cutaneous polyarteritis nodosa or, if accompanied by significant lobular panniculitis, nodular vasculitis/erythema induratum. In other cases, cutaneous vascular damage (fibrinoid necrosis, muscular vessel wall disruption, or endarteritis obliterans) will be mediated by a nonneutrophilic inflammatory infiltrate. Eosinophilic vasculitis can be a primary (idiopathic) process that overlaps with hypereosinophilic syndrome, or it can be a secondary vasculitis associated with connective tissue disease or parasite infestation. Authentic cutaneous granulomatous vasculitis (versus vasculitis with extravascular granulomas) can represent a cutaneous manifestation of giant cell arteritis, an eruption secondary to systemic disease such as Crohn's disease or sarcoidosis, or a localized disorder, often a post-herpes zoster (HZ) phenomenon. Lymphocytic vasculitis is a histologic reaction pattern that correlates with broad clinical differential diagnosis, which includes connective tissue disease - mostly systemic lupus erythematosus (SLE), endothelial infection by Rickettsia and viruses, idiopathic lichenoid dermatoses such as perniosis or ulcerative necrotic Mucha-Habermann disease, and angiocentric cutaneous T-cell lymphomas. Skin biopsy extending into the subcutis, identifying the dominant inflammatory cell and caliber of vessels affected, extravascular histologic clues such as presence of lichenoid dermatitis or panniculitis, and correlation with clinical data allows for accurate diagnosis of these uncommon vasculitic entities.

Renal manifestations of the antiphospholipid syndrome

Although renal manifestations of the antiphospholipid syndrome (APS) have received scarce attention until recently, the kidney probably is a major target organ in APS. Thrombosis may develop at any location within renal vessels, ie, renal artery trunk or branches, intrarenal arteries or arterioles, glomerular capillaries, and renal vein. The clinical consequences consist of highly variable degrees of proteinuria; systemic hypertension ranging from mild to malignant; cortical necrosis; thrombotic microangiopathy, pregnancy-associated or not; and slowly to rapidly progressive renal failure that may require dialysis. These events occur mainly in the course of systemic lupus erythematosus or of "primary" APS. Renal involvement is a frequent feature of the catastrophic APS. A high prevalence of antiphospholipid antibodies has been reported recently in patients with end-stage renal failure, but their clinical significance remains to be determined.