Causes, Triggers, and Risk Factors
Allergies and sensitivities. Allergies underlie many cases of asthma. An allergy is an inappropriate immune response against an innocuous compound. A wide variety of environmental allergens can cause an asthma attack (Young 2011), including food allergies (Wang 2011).
For those whose asthma is associated with environmental allergies, immunotherapy (e.g., “allergy shots” or sublingual immunotherapy) may help prevent exacerbations (Abramson 2003; Morris 2012, Fujimura 2012).
In the case of food sensitivities, experimental research suggests that chronic, low-level inflammatory reactions triggered by an immune response to food particles may set the stage for airway inflammation (Lee 2011; Shakib 1986). Those with asthma would be wise to test to see if they are producing high levels of IgG antibodies towards any particular food(s). Some evidence suggests that IgG antibody testing is able to detect immune reactions less severe than an overt allergy, but that nonetheless may trigger inflammation (Lee 2011; Shakib 1986; Oehling 1984).
More information about the role of allergies and sensitivities in triggering inflammatory reactions throughout the body is available in the Allergies protocol.
Tobacco smoke. Studies have consistently shown a relationship between smoking and asthma. Smoking is also related to decreased asthma control, higher risk of asthma attacks, and death. Improvements in lung function and asthma symptoms have been observed among those who quit smoking (Stapleton 2011).
Occupational exposure. Occupations commonly associated with asthma include woodworking, detergent manufacturing, some health care professions, and baking (PubMed Health 2011; Bakerly 2008; Vandenplas 2011).
Infections. A variety of common viral infections acquired during infancy and early childhood appear to increase the risk of childhood wheezing episodes that may eventually lead to asthma (Lemanske 2010). In contrast, other evidence suggests that childhood exposure to microbial pathogens and foreign peptides may protect against the development of childhood asthma – a theory known as the hygiene hypothesis (Murk 2011; Mannie 2010).
Medications. Certain medications, including non-steroidal anti-inflammatory drugs (NSAIDs) and ACE-inhibitors, can trigger an asthma attack in some people (Sanfiorenzo 2011).
Exercise.Exercise can trigger asthma exacerbations, so people with asthma should exercise with caution (NHLBI guidelines).
Other medical conditions commonly associated with asthma include chronic rhinitis, chronic sinusitis/rhinosinusitis, gastroesophageal reflux disease (GERD), obstructive sleep apnea, chronic obstructive pulmonary disease (COPD), hormonal disorders, obesity, depression, and anxiety. Stress has been associated with asthma as well (Yonas 2012).These conditions may share some pathophysiological mechanisms with asthma and may influence its expression. Associated diseases may also influence how a patient with asthma responds to treatment. Likewise, the asthmatic condition and the inflammatory processes in asthma may influence how these associated conditions develop or progress over time (Boulet 2011; Cazzola 2011).