Diagnosis, Management, Immunotherapy Options for Patients With Allergic Asthma

Approximately 25 million people in the United States are diagnosed with asthma. The most common type of asthma is allergic asthma, with about 60% of asthma cases caused by allergies.¹ Sean P. Duffy, MD, answers questions about managing patients with allergic asthma. Dr Duffy is a pulmonologist at Temple Lung Center and an associate professor of clinical thoracic medicine and surgery at the Lewis Katz School of Medicine at Temple University.

Consultant360: Why is it important to take a thorough medical history when diagnosing a patient with allergic asthma?

Dr Sean P. Duffy: A thorough medical history provides the basis for making any diagnosis but can be especially important in asthma. In asthma, the medical history provides not only the framework for making the diagnosis but also the severity of the disease and the measure of control a patient has over the disease. It is extremely important to understand the patient’s asthma-specific history. A history of exacerbation is the greatest predictor of future exacerbation. Furthermore, a history of severe exacerbation, such as admission to the hospital requiring mechanical or noninvasive ventilation, should set off the alarms that prompt an aggressive approach to treatment.

Regarding control, a thorough history is the best way to understand the burden asthma has on a patient’s daily life. To assess control, the physician should review the frequency of daytime and nighttime symptoms, and the frequency of rescue inhaler use at each visit. Physicians also need to understand the effect the patient’s symptoms have on the patient’s daily life. This can prove to be a difficult task as many patients with asthma will minimize their daily-symptom burden. For this reason, I will often ask something like “Is there anything you like to do that you can no longer do because of your asthma symptoms?” This type of questioning can help to get the patient thinking more deeply about the effect living with asthma has had on the patient’s quality of life.

Additionally, there are many environmental factors that are important to the management of asthma. Thus, it is important to know what the patient is exposed to in the home and at work, including cigarette smoke, animals, down pillows, dust, mold, fumes, pollen, and other outdoor allergens.

C360: What are appropriate tests used to establish the diagnosis of allergic asthma and/ or a sensitivity to specific allergens?

SD: Testing can also be helpful in establishing the diagnosis of asthma and can be especially helpful in establishing the phenotype (allergic vs non-allergic) in patients with asthma. Patients with suspected asthma should undergo lung-function testing to determine the presence of variable expiratory airflow limitation.¹ This is often done with spirometry before and after bronchodilator administration or with bronchoprovocation testing. Phenotyping can be done with additional testing to measure eosinophils in sputum or peripheral blood, total immunoglobulin (IgE), and/or fractional exhaled nitric oxide. In addition, skin prick allergy testing can be used to identify specific allergens. Blood tests for specific IgE can also be performed but are generally more expensive and less sensitive than a skin prick test performed in an experienced center.

C360: How should a patient with allergic asthma be managed?

SD: The mainstay of therapy in any patient with asthma is inhaled corticosteroids (ICS), along with inhaled bronchodilators, long-acting beta-agonists (LABA), or short-acting beta-agonists. Initial therapy recommendations range from as-needed ICS to high-dose ICS-LABA. Initial medication choices are based on the severity of presenting symptoms and the risk for future exacerbations.² In patients with difficult-to-control allergic asthma, biologic therapies and immunotherapy provide additional potential adjunct treatment options.

C360: What are the possible benefits and possible risks of immunotherapy? In which patients would immunotherapy be appropriate?

SD: Immunotherapy can provide benefits when a specific allergy can be identified and plays a significant role in the patient’s symptoms. Avoidance of the allergen is typically the first-line method of preventing symptoms in these cases, but avoidance is not always possible. The most common allergens treated with immunotherapy are pollens and dust mites. The benefits of such treatment include a decrease in rescue inhaler use and an improvement in symptom scores. Major adverse events are very uncommon, but the risk of anaphylaxis is a concern with immunotherapy.²

C360: What are the different types of immunotherapies that are approved by the FDA?

SD: The FDA has approved 2 types of immunotherapies. Subcutaneous immunotherapy involves the subcutaneous injection of escalating doses of extract of a clinically relevant allergen. Sublingual immunotherapy (SLIT) involves the sublingual administration of the clinically relevant allergen. In both types of immunotherapies, the risks and potential benefits must be discussed with the patient, as the process of immunotherapy can be cumbersome with frequent visits and prolonged courses of therapy. Recent Global Initiative for Asthma and Prevention guidelines recommend SLIT in patients with allergic rhinitis and forced expiratory volume in 1 second greater than 70% who are sensitized to dust mites and have persistent asthma symptoms despite low- or medium-dose ICS.²

C360: What are some common mistakes you see when patients use a metered-dose inhaler? What should clinicians be aware of?

SD: Patients often make several mistakes when using metered-dose inhalers. It is important to review proper inhaler technique and/or provide resources, such as instructional pamphlets or videos, at each patient encounter. Some common mistakes include but are not limited to; failure to fully exhale before use, failure to create a good seal with the lips, poor timing of inhalation; and failure to complete the first inhalation and repeat all steps for the second inhalation. Some of these mistakes can be mitigated with the proper use of a spacer.

C360: Is there a relationship between obesity and allergic asthma?

SD: Obesity is generally a risk factor for having asthma. Patients with a BMI greater than 30 are more likely to have asthma than patients with a normal BMI. There is a subset of patients with asthma and obesity, often female and diagnosed at a later age, that is less likely to have allergic asthma.³ Regardless, patients with obesity and asthma should be evaluated and treated in the same manner as patients with asthma and a normal BMI.

References:

1. Cleveland Clinic. Allergic Asthma. Updated November 23, 2020. Accessed August 24, 2022. https://my.clevelandclinic.org/health/diseases/21461-allergic-asthma
2. Global Initiative For Asthma. Global Strategy for Asthma Management and Prevention (2022 update). Accessed August 24, 2022. https://ginasthma.org/gina-reports/
3. Holguin F, Bleecker ER, Busse WW, et al. Obesity and asthma: an association modified by age of asthma onset. J Allergy Clin Immunol. 2011;127(6):1486-93.e2. doi:10.1016/j.jaci.2011.03.036