Hereditary angioedema type 2 presented as an orbital complication of acute rhinosinusitis

Hereditary angioedema is an autosomal dominant and life-threatening disorder characterized by recurrent episodes of non-pitting edema affecting the skin, respiratory system and digestive tracts and caused by a congenital deficiency or function defect of the C1 esterase inhibitor. Preseptal cellulitis is defined as an infection of the tissues of the anterior orbital septum. It is generally caused by complications from an upper respiratory tract infection, dacryocystitis, dermal infection, and, rarely, sinusitis. The disease presents with orbital pain, edema on the eyelids, erythema, and fever. In this case, a child with hereditary angioedema type 2 who presented as mimicking a complication of acute sinusitis is discussed.