Severe Steroid-Dependent Idiopathic Angioedema with Response to Rituximab

The document reports on a 19-year-old woman with severe, recurrent idiopathic angioedema unresponsive to conventional treatments, including antihistamines and corticosteroids. Her condition was steroid-dependent and not linked to any known triggers or underlying disorders. After failing to respond to standard therapies and experiencing adverse effects, she was treated with rituximab, an anti-CD20 monoclonal antibody, which led to significant improvement and allowed for steroid tapering. She remained in remission for 9 months and responded well to a second rituximab course after a flare-up. Additionally, her angioedema episodes decreased after discontinuing dutasteride, a drug known to affect bradykinin metabolism, which is implicated in angioedema. This case suggests rituximab's potential efficacy in treating idiopathic and autoimmune angioedema and highlights the role of antiandrogen drugs in affecting bradykinin levels, which could contribute to angioedema.