D3.283 - Taming the Unpredictable: Omalizumab’s Role in Idiopathic anaphylaxis and chronic spontaneous urticaria
Case report
Introduction
Idiopathic anaphylaxis (IA) and chronic spontaneous urticaria (CSU) are complex conditions, particularly when patients do not respond to conventional therapies such as high-dose antihistamines and corticosteroids. Omalizumab, a monoclonal antibody targeting IgE, has emerged as a promising therapeutic option for refractory cases.
Case Report
We present the cases of two female patients, aged 63 and 67 years, with severe forms of idiopathic anaphylaxis (IA) and chronic urticaria (CU). The first patient experienced recurrent episodes of IA and CU, which significantly impacted her quality of life. The second patient had a history of multiple episodes of idiopathic anaphylaxis with elevated tryptase levels, as well as some mild episodes of urticaria and angioedema, though without anaphylaxis. Both patients required emergency room treatment for anaphylaxis.
Systemic mastocytosis was excluded, and extensive investigations into other causes of anaphylaxis were conducted for both patients; however, no specific trigger factors were identified.
Both patients were started on omalizumab at the standard dose of 300 mg every four weeks. Over the course of two years, the first patient demonstrated complete control of her CSU symptoms and experienced no further episodes of anaphylaxis. A similar improvement was observed in the second patient, who experienced only one episode of idiopathic anaphylaxis during the two years following the initiation of omalizumab therapy, representing a significant reduction in episode frequency compared to prior periods[FR1] . Both patients tolerated the treatment well, with no significant adverse effects reported.
Discussion
These cases highlight the potential of omalizumab as a highly effective treatment for IA and CSU, particularly in patients who are refractory to other therapies and for whom no identifiable cause has been found. By targeting IgE and inhibiting mast cell and basophil activation, omalizumab significantly reduced the number and the risk of anaphylaxis, while providing sustained urticaria symptom control and significantly improving patients' quality of life.
