C1 Esterase Inhibitor Deficiency in an Indian Female: A Rare Case Report and a Review of Literature with Treatment Update.

introductionHereditary Angioedema (HAE) is a rare, autosomal dominant disorder characterized by episodic, non-pruritic, non-pitting swelling of the skin, respiratory tract, and gastrointestinal system resulting from C1 esterase inhibitor (C1-INH) deficiency or dysfunction. It is frequently underdiagnosed, particularly in developing countries like India, due to its nonspecific presentation and overlap with allergic angioedema. CASE PRESENTATION: We report a case of a 28-year-old Indian woman who presented with a fivemonth history of progressive facial and periorbital swelling. She had no urticaria, known allergies, or systemic symptoms and did not respond to antihistamines or corticosteroids. The initial workup revealed normocytic anemia and elevated inflammatory markers, with normal renal, hepatic, thyroid, and autoimmune profiles. Radiological evaluation showed bilateral pre-septal edema. Complement C4 was normal; however, serum C1-INH level was markedly reduced, confirming type I HAE. She responded well to intravenous plasma-derived C1-INH concentrate (Cinryze). Unfortunately, she succumbed to a later episode of upper airway edema, highlighting the life-threatening potential of untreated or delayed HAE.

conclusionThis case emphasizes the need for high clinical suspicion of HAE in patients with unexplained, non-histaminergic angioedema, especially when conventional therapies fail. Early biochemical confirmation and targeted therapy are essential for effectively managing and preventing fatal complications.