A Confounding Case of Inherited Factor V Deficiency Complicated by Inhibitors at First Presentation.

INTRODUCTION: Inherited factor V deficiency / Owren's disease has varied clinical manifestations ranging from asymptomatic laboratory abnormalities to massive hemorrhage. The acquired form due to inhibitors following antibiotic therapy, infection, or surgery is less common, and spontaneous development of inhibitors is not known. CASE REPORT: An 18-year-old boy presented with bleeding axillary and groin ulcers. At the age of 15, due to recurrent epistaxis and gum bleed, he was diagnosed with acquired factor V deficiency with positive inhibitor screen and treated with fresh frozen plasma (FFP) transfusion and temporary azathioprine. Coagulation workup at his current presentation also revealed acquired factor V deficiency with presence of inhibitors. The tests were repeated after 6 weeks of intermittent FFP transfusion, and the differences observed included negative inhibitor screen and complete correction on mixing studies, but factor V level was 2%. DISCUSSION: Evidence of inhibitors at presentation favored acquired disease. However, younger age of onset, detection of inhibitors 1 year after first episode of self-regressing bleed, lack of identifiable triggers, and persistent bleeding with reduced factor levels after disappearance of inhibitors favored inherited factor V deficiency. CONCLUSION: In this case report, we have described an interesting case of severe inherited factor V deficiency with spontaneous appearance and disappearance of inhibitors exhibiting nonspecific factor inhibitory activity.