D1.319 - Efficacy of Omalizumab in Refractory Cholinergic Urticaria and Cholinergic Anaphylaxis: A Case Series

Background: Cholinergic urticaria (CholU) is a chronic inducible urticaria triggered by physical exercise, emotional stress and increases in core body temperature; leading to significant disease burden and impaired quality of life. In some patients, CholU may progress to cholinergic anaphylaxis. Standard treatment with high-dose second-generation H1-antihistamines is often insufficient. While omalizumab is effective in chronic spontaneous urticaria, evidence for its use in CholU, particularly when associated with anaphylaxis, remains limited.

Methods: We report a case series of two patients with CholU complicated by anaphylaxis, refractory to high-dose antihistamines, who were treated with omalizumab. Clinical assessment included detailed history, exclusion of food-dependent exercise-induced anaphylaxis, exercise provocation testing, and validated disease control and quality-of-life questionnaires. Treatment response was evaluated clinically and through longitudinal questionnaire scores.

Results: The first patient was a 15-year-old girl with CSU and CholU triggered by exercise and strong emotions, associated with a high disease burden. At symptom onset, she experienced a single episode of anaphylaxis during physical exercise. Despite treatment with double- and subsequently quadruple-dose second-generation H1-antihistamines, she continued to present daily flares and discontinued sports activities. Exercise provocation testing was positive. Omalizumab led to complete symptom control maintained over 12 months, allowing gradual withdrawal of antihistamines and marked improvement in UCT (from 5 to 14) and CU-QoL (from 52 to 25).

The second patient was a 23-year-old woman with exercise-induced CholU and recurrent cholinergic anaphylaxis, presenting with urticaria and bronchospasm, resulting in significant disease burden and impaired quality of life. Despite treatment with quadruple-dose second-generation H1-antihistamines, disease control remained poor (UCT 6/16, CU-QoL 58.7%, AECT 2/16, AE-QoL 73.5%, CholU-QoL 76.8%). Omalizumab was initiated at a dose of 300 mg weekly, achieving complete disease control after the first two administrations, despite ongoing daily physical exercise (UCT 16/16, CU-QoL 0%, AECT 16/16, AE-QoL 0%, CholU-QoL 0%). Antihistamines were gradually discontinue while maintaining sustained control.

Conclusion: Omalizumab provided effective and sustained control of CholU complicated by cholinergic anaphylaxis, with substantial improvement in quality of life, even in the context of continued physical exercise, progressive reduction and discontinuation of antihistamines.