Recurrent Angioedema Misdiagnosed as Anaphylaxis in Hereditary C1 Inhibitor Deficiency: A Review of Published Cases
DOI:
https://doi.org/10.5281/zenodo.22279527Keywords:
Hereditary angioedema, C1 inhibitor deficiency, Anaphylaxis, Misdiagnosis, BradykininAbstract
Background: Hereditary angioedema due to C1 inhibitor deficiency (HAE-C1INH) is a rare, bradykinin-mediated disorder
producing recurrent, non-pruritic, non-urticarial swelling frequently mistaken for allergic or anaphylactic angioedema, delaying
life-saving treatment. Objective: To review published case reports, cohorts and guidelines documenting misdiagnosis of HAE-C1INH as anaphylaxis or allergy. Methods: Narrative review of case reports, cohort/registry studies, systematic reviews and society guidelines identified through verified bibliographic search. Findings: Diagnostic delay across published cohorts ranges from 3.9 to 26 years, and roughly 44% of patients carry a prior misdiagnosis, most often allergic angioedema or appendicitis, nearly octupling delay (13.3 versus 1.7 years). Published cases document adrenaline, antihistamines and corticosteroids failing outright, with resolution only after bradykinin-targeted therapy. Serum C4 alone is an insufficient screen (sensitivity 81%). Conclusions: Recognising the absence of urticaria and pruritus, slow evolution of swelling, and failure of standard anaphylaxis treatment, paired with C4 and C1-INH testing, can substantially shorten diagnostic delay and reduce fatal laryngeal attacks.
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