AUTHOR=Buttgereit Thomas , Fijen Lauré M. , Vera Carolina , Bergmann Karl-Christian , Maurer Marcus , Magerl Markus TITLE=Case report: Recurrent angioedema: Diagnosing the rare and the frequent JOURNAL=Frontiers in Medicine VOLUME=9 YEAR=2022 URL=https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2022.1048480 DOI=10.3389/fmed.2022.1048480 ISSN=2296-858X ABSTRACT=

Hereditary angiodema with normal C1 inhibitor and unknown mutation (HAE-nC1INH-UNK), an exceedingly rare subtype of HAE, appears to be often diagnosed in patients who do not have this condition, but have mast cell-mediated angioedema. Here, we report two patients diagnosed with HAE-nC1INH-UNK by their physicians, who referred them to our center for treatment continuation with costly kallikrein-kinin-system targeted therapies. We describe how we established the correct diagnosis of recurrent mast cell-mediated angioedema after thorough investigation of both patients and initiated effective treatment with omalizumab. Also, we present and discuss the consensus criteria for diagnosing the very rare condition HAE-nC1INH in light of recent research and based on our own clinical experience. In conclusion, HAE-nC1INH-UNK should only be considered after more common differential diagnoses, i.e., mast cell-mediated angioedema, have thoroughly been investigated and ruled out. This approach reduces both the patients’ disease burden and healthcare costs and contributes to meaningful research.