What Is Intermittent Asthma?
Aaron S.
Chidekel,
MD
Intermittent asthma is the mildest form of asthma, but it is not a type of asthma that is completely risk-free.1 In fact, in the most recent asthma guidelines, the “mild” qualifier that previously was associated with intermittent asthma has been removed to emphasize this very point. However, in intermittent asthma, impairment will be low or absent, and airway symptoms will be infrequent (Table 29-1). In fact, because asthma is defined as a disease of chronic airway inflammation, in some ways, the notion of intermittent asthma is something of a paradox. After all, how can a patient have intermittent, chronic airway inflammation? Clearly, intermittent asthma does exist, and depending upon the patient population in your practice, you may see it frequently or infrequently. Still, many patients will have this form of asthma because milder forms of asthma are most common, and these mild patients will require ongoing clinical follow-up, appropriate medical management, and, as with more severely asthmatic patients, a clear action plan to follow.
To address the paradox of airway inflammation in intermittent asthma, it is helpful to consider patients with intermittent asthma as individuals whose airway inflammation has not reached a certain critical threshold to result in the more significant burden of symptoms or lung function abnormalities that are seen in persistent asthma. The level of airway inflammation they experience may be truly intermittent, but it is more likely that it is mild enough that the patient has minimal and intermittent symptoms of asthmatic airway inflammation: cough, wheeze, and mucous production. Similarly, the airways of these patients are not sufficiently inflamed to result in detectable abnormalities on lung function testing, and the risk of airway remodeling is minimal. As normal lung function does not eliminate the presence of truly persistent asthma, spirometry should be followed over time to ensure that the patient’s level of lung function remains normal.
Individuals with intermittent asthma will have minimal symptoms. This is often defined in asthma guidelines in the United States as having to use a rescue inhaler less than twice weekly during waking hours and less than twice per month to treat nocturnal symptoms/awakenings. Any level of symptoms that is greater than this will no longer fit with the definition of intermittent asthma and will need to be treated with daily controller medication. Similar to this low level of impairment, patients with intermittent asthma will have low levels of risk associated with their condition. They will have infrequent periods of increased symptoms, and these “flares” will not result in the need for oral corticosteroid therapy or emergency asthma care more than once per year. Individuals with intermittent asthma may have exercise-induced bronchospasm and use a short-acting bronchodilator, such as albuterol, prior to exercise to prevent asthma symptoms. Even when used frequently in this fashion, a patient will still meet the criteria for intermittent asthma as long as he or she is not using the short-acting bronchodilator for rescue. It is straightforward and important to quantify these parameters in an asthma follow-up visit and to track them over time in any individual patient to ensure good control of intermittent asthma.
The evaluation of a patient with intermittent asthma will mirror that of a patient with more significant asthma. The likelihood of asthma-related co-morbidities remains, and it is prudent to screen for these as indicated. Atopy and allergic rhinitis often accompany intermittent asthma and should be treated with medications and/or environmental control. Ongoing follow-up and clinical monitoring are also recommended to ensure that the patient’s asthma is remaining intermittent and well-controlled. Use of symptom scores, asthma assessment tools, and objective measures of lung function (Figures 29-1 and 29-2) are just as much a part of the management of intermittent asthma as for persistent asthma.
Figure 29-1. Representative flow-volume loop (spirometry) from a patient with intermittent asthma showing a normal flow-volume loop with normal predicted values for age.
Figure 29-2. Representative pre- (red) and post- (blue) bronchodilator spirometry from a patient with intermittent asthma demonstrating normal to supra-normal flows and volumes. Bronchial hyper-reactivity is indicated pictorially by the increased size of the flow-volume loop in the post-bronchodilator effort.
The treatment of intermittent asthma is straightforward. A patient should be instructed in the use of a short-acting beta-agonist for airway symptoms, and an asthma action plan is constructed that reflects this.2 If a patient is not using a short-acting beta-agonist for exercise, his or her need for refills should be minimal, and he or she should be using no more than 1 or 2 inhalers per year. More frequent requests for medication refills should raise the possibility of more persistent asthma with under-reporting of symptoms, and the patient should be re-assessed. Some patients may also have a prescription for an inhaled corticosteroid to use during brief periods of increased symptoms, but this recommendation is somewhat controversial.3,4 If a patient requires more than this level of medical management, then he or she is stepped up to a persistent level of asthma, and his or her care plan is adjusted to reflect this change.
The prognosis of intermittent asthma is excellent. While most individuals with intermittent asthma tend to stay intermittent, this must not give the patient or physician a false sense of security. Patients still need asthma education and an action plan for periods of wellness as well as in the event of a severe flare. Finally, just like patients with more significant asthma burden, individuals with intermittent asthma need and deserve ongoing follow-up to ensure their continued safety, asthma control, and good health.
References
1. Shahid N, Fitzgerald JM. Current recommendations for the treatment of mild asthma. J Asthma Allergy. 2010;3:169-176.
2. Boushey HA, Sorkness CA, King TS, et al. Daily versus as-needed corticosteroids for mild persistent asthma. N Engl J Med. 2005;352:1519-1528.
3. National Asthma Education and Prevention Program. Expert panel report 3 (EPR-3): guidelines for the diagnosis and management of asthma. Bethesda, MD: National Heart, Lung, and Blood Institute, 2007. NIH publication no. 08-4051.
4. Turpeinen M, Nikander K, Pelkonen AS, et al. Daily versus as-needed inhaled corticosteroid for mild persistent asthma (The Helsinki early intervention childhood asthma study). Arch Dis Child. 2008;93:654-659.