Interferons beta have vasoconstrictive and procoagulant effects: a woman who developed livedo reticularis and Raynaud phenomenon in association with interferon beta treatment for multiple sclerosis.

A 31-year-old woman with MS developed livedo reticularis and secondary Raynaud phenomenon 2.5 years after introduction of interferon beta-1b. The symptoms disappeared after withdrawal of the drug. Livedo reticularis and Raynaud phenomenon as well as pulmonary arterial hypertension, venous sinus thrombosis, pulmonary embolism and renal thrombotic microangiopathy have all been described in association with interferon beta therapy. These complications strongly suggest that type I interferons have vasoconstrictive and procoagulant effects with potentially serious systemic complications.