Case Report: Hereditary Angioedema Accompanied by Chronic Spontaneous Urticaria.

Purpose: Hereditary angioedema (HAE) is a rare genetic disorder characterized by recurrent edema of the skin and tissues. Chronic spontaneous urticaria (CSU) is recurrent urticaria that lasts for more than 6 weeks without an apparent cause. It has long been believed that HAE does not occur with CSU. Patient and Case Description: Herein, we report a case of definite HAE with CSU. The patient was diagnosed with CSU due to recurrent clinical symptoms. After treatment with omalizumab, the symptoms of CSU improved, but there were still unpredictable recurrent episodes of edema. For further diagnosis, genetic testing and other laboratory examinations were performed, and it was confirmed that the patient also had HAE. Results: After treatment with omalizumab, the pruritus and erythema improved, confirming the diagnosis of CSU. The diagnosis of HAE (C1-INH deficiency, type 1) was established by WES, C1-INH concentration (0.08 g/L) and C4 level (25 mg/L) measurements, which explained the recurrent edema. Conclusion: We report a case with both HAE and CSU, suggesting that doctors should consider the possibility of co-existence of diseases in diagnosis, and attention should be paid to the timing of different treatment options such as omalizumab in the course of treatment.