The most appropriate treatment is omalizumab. Severe asthma occurs in 10% of patients with asthma and is associated with long-term treatment with high-dose glucocorticoids, frequent exacerbations, and high health care utilization, as in this patient. This patient's asthma has not been controlled despite aggressive nonpharmacologic interventions and treatment with multiple drugs. Omalizumab, a humanized monoclonal antibody directed at IgE, is the first biologic agent approved by the FDA for use in asthma. Administered subcutaneously every 2 to 4 weeks, omalizumab is indicated in patients with moderate to severe persistent asthma with the following characteristics: (1) symptoms inadequately controlled with inhaled glucocorticoids, (2) evidence of allergies to perennial aeroallergens, and (3) serum IgE levels between 30 and 700 U/mL (30-700 kU/L) (normal range, 0-90 U/mL [0-90 kU/L]). Although it is very expensive, omalizumab has been shown to reduce emergency department visits and appears to be cost effective in appropriately selected patients; it is not indicated for use in patients other than those meeting these treatment parameters.

Allergen immunotherapy (allergy shots) can be useful when a single trigger is identified or when a trigger is consistently the source of asthma instability. It is a reasonable longer-term plan in this patient; however, immunotherapy may take 3 to 5 years to achieve a noticeable therapeutic effect. Omalizumab would be expected to provide more immediate control of her asthma than is possible with allergen immunotherapy.

This patient has required frequent and high doses of systemic glucocorticoids and is exhibiting side effects (skin thinning and cushingoid facies). Because of the long-term detrimental effects of prolonged systemic glucocorticoid therapy, particularly in this younger patient, daily glucocorticoid therapy would not be appropriate.

Other forms of immune modulation, such as with tumor necrosis factor–α inhibitors (such as infliximab) or other immunosuppressive agents (such as cyclophosphamide and azathioprine), have not been shown to be effective in controlling severe asthma and are associated with a high level of adverse effects in these patients.