Omalizumab for Chronic Urticaria

Overview / Definition Chronic urticaria is defined as the presence of urticaria (hives) for six weeks or longer. It can be classified into chronic spontaneous urticaria (CSU), where hives occur without an identifiable trigger, and chronic inducible urticaria, where urticaria is triggered by specific stimuli. Epidemiology Chronic urticaria affects approximately 0.5% to 5% of the population at some point in their lives. The condition is more prevalent in women than in men, with a ratio of approximately 2:1. Onset can occur at any age, but it most commonly affects individuals between 20 and 40 years of age. Pathophysiology / Mechanism The pathophysiology of CSU involves the release of histamine and other inflammatory mediators from mast cells, often triggered by IgE antibodies. Omalizumab works by binding to free IgE, preventing it from attaching to mast cells and basophils, thus inhibiting the release of inflammatory mediators and reducing the frequency and severity of urticaria episodes. Clinical Presentation Patients with chronic urticaria typically present with: Itchy wheals: Raised, red, and itchy welts on the skin. Angioedema: Swelling of deeper layers of skin, often affecting the face, lips, or extremities. Fluctuating course: Symptoms may wax and wane, and patients can experience periods of remission. Symptoms can significantly impact the quality of life, leading to sleep disturbances, anxiety, and depression. Diagnosis / Workup The diagnosis of chronic urticaria is primarily clinical. A thorough history and physical examination are essential. The following steps may be included in the workup: History: Duration of symptoms, triggers, and associated symptoms. Physical examination: Evaluation of skin lesions and presence of angioedema. Laboratory tests: May include complete blood count, thyroid function tests, and specific IgE tests if an allergic trigger is suspected. In cases of chronic inducible urticaria, specific provocation tests may be warranted. Treatment