What is Asthma?
Asthma is a long-term condition that inflames the airways (which carry air in and out of your lungs). Inflammation causes these airways to narrow, which makes it difficult to breathe. Your airways might also fill up with mucus or even fluid. Asthma can be a lifelong condition and is potentially fatal. It affects both adults and children, and almost 12% of people globally suffer from it [1].
What are the Causes of Asthma?
Although there is no firm consensus as to the exact cause of this disorder, some experts believe it is caused by a complex interaction between genes and the environment. Asthma symptoms are triggered by a variety of factors and can differ from person to person. Sometimes, the triggering factors can change over time [2].
Allergens – triggers of an allergic reaction – are one of the most common instigators of asthma symptoms. These can include dust mites, molds, pets, grass, trees and weeds, cockroach and mouse faeces, and other forms of pest waste. Where people encounter allergens, their immune system might mount a response, causing swelling in the lungs’ airways and making it harder to breathe [3, 4].
Asthma might also be triggered by non-allergic factors: asthma caused by breathing cold air, e.g.; some medications/inhalers, household chemicals, infections (eg, by colds and influenza), those related to outdoor air pollution, and tobacco smoke. Occupational asthma results from exposure to chemicals or industrial specks of dust at work, and exercise-induced asthma occurs when a person does physical exercise, such as in dry air [2].
Other risk factors include family history; viral respiratory infections; allergens, chemicals, or smoke exposure; sex; age; race and ethnicity; allergic conditions such as eczema and hayfever; and overweight and obesity [5].
What are Lung Nodules?
Lung nodules are growths on the lungs that are usually smaller than 3 centimetres in diameter. They are often found incidentally, as part of imaging tests done for other reasons. Most lung nodules are non-cancerous (benign) growths that may be caused by scar tissue, an old infection or an irritant in the air [6, 7, 8].
Causes of Lung Nodules
Lung nodules might stem from scars, a healed infection, an airborne irritant or rarely, even rheumatoid arthritis, a painful inflammatory disease in joints. And then some are cancerous growths [6, 7].
Nodules are benign lung growths that can be the result of conditions that lead to lung inflammation or scar tissue on the lungs, including lung infections, for example, pulmonary tuberculosis, granulomas, non-infectious diseases such as sarcoidosis and rheumatoid arthritis, or fungal infections from inhalation of spores. They can also arise from neoplasms – abnormal growths that can be benign or malignant – or cancerous tumours, such as lung cancer, lymphoma or sarcoma [8].
One study from northern China identified risk factors for lung nodules that included increasing age, smoking history, secondhand smoke exposure, dust, history of lung disease and family history of cancer. Greater consumption of vegetables, legumes and tea was associated with lower risk [9].
Incidentally, these lung nodules could also be due to SARS-CoV-2 infection of the lungs by the virus responsible for COVID-19. The prevalence of nodules on CT scans of people testing positive for COVID-19 is 3% to 12% [6, 7].
Can Asthma Cause Lung Nodules?
Asthma itself does not directly cause lung nodules. However, certain conditions associated with asthma can lead to the formation of lung nodules.
One such condition is allergic bronchopulmonary mycosis, which should be considered in patients with asthma presenting with abnormal pulmonary nodules [10]. Another condition is eosinophilic pneumonia, which has been reported in a patient with asthma and presented with nodular shadows in the lungs [11].
Because lung nodules can occur with chronic eosinophilic pneumonia, a poorly understood and very rare form of asthma the authors considered the diagnosis [12].
These are not specific to asthma, ranging in aetiology from infectious to non-infectious to malignant. They include other inflammatory diseases or stigmas, such as fungal infections, non-infectious diseases like sarcoidosis and rheumatoid arthritis, and of course neoplasms – abnormal growths that can be benign or produce findings suggestive of malignant neoplasms, or cancer [8].
Conclusion
And though asthma doesn’t necessarily cause nodules, some conditions brought about by asthma can do so. If something is causing an asthmatic to cough, a nodule might be the culprit. Having it checked out by a healthcare professional is recommended because treatment will vary depending on its root.