 The study of the peripheral microvasculature from patients’ biopsy specimens has not evidenced gross anomalies, disrupted angiogenesis, or inflammatory cells or other factors suggestive of a disorder prone to damage the blood vessels by inflammation.The absence of structural abnormalities is thus consistent with the hypothesis of some kind of defective but curiously reversible cellular phenomenon in the capillaries.Studies suggest that the presence of various inflammatory factors during episodes of SCLS may explain the temporarily abnormal permeability of the endothelial cells lining the inner surface of the capillaries.