Allergies and asthma are often thought of as childhood disorders, but they can be just as important in adults, according to Dr. Sameer K. Mathur of the University of Wisconsin School of Medicine. He reported that these conditions are often unrecognized or under-treated in older people. Many clinical trials for asthma medication have an upper age limit of 55 to 65, while the number of older patients with asthma is expected to double within the next 20 years. Thus, more data are needed.
Certain other diseases, called co-morbidities, make the management of asthma more difficult. These include gastroesophageal reflux disease, allergic rhinitis, chronic rhinosinusitis, and vocal cord dysfunction, all of which may be especially significant in older adults. Women are particularly susceptible to vocal cord dysfunction. The NIH guidelines for treating asthma include a caution that physicians should watch more carefully for side effects in older patients, and that medication used to treat co-morbidities may have an effect on asthma.
Asthma at all ages involves airway inflammation. In younger patients, asthma is often associated with allergies and referred to as extrinsic. Asthma that first appears in older patients is typically non-allergic and referred to as intrinsic. The inflammatory characteristics are remarkably similar, but intrinsic asthma is a more severe type with greater airflow obstruction and lung function decline.
Immune function in general tends to decline with age. This phenomenon is called immunosenescence, and contributes to more frequent infections and an increased incidence of some types of autoimmune disease. Up to 80 percent of asthma exacerbations in adults are triggered by viral respiratory infections, so a decline in the body's ability to fight infection can result in worse asthma symptoms.
In addition, older patients have a less acute perception of their asthma symptoms. Dr. Stephen C. Allen and coworkers studied the ability to sense airflow resistance as a function of age, and found that older people are less able to detect increased resistance. This could be a handicap for self-management of asthma.