Can Asthma Cause Lung Nodules?

In this blog, we will provide a brief insight into asthma, a long-term condition that inflames the airways, and lung nodules, small growths on the lungs. We will explore the causes, triggers, and risk factors of these conditions, and explore the potential connection between them.
Greta Daniskova

Greta Daniskova

Greta is a BSc Biomedical Science student at the University of Westminster, London.

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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.

Greta Daniskova

Greta Daniskova

Greta is a 2nd-year student currently pursuing her Bachelor's Degree in Biomedical Sciences at the University of Westminster in London. Currently, in her second year of undergraduate studies, she exhibits a keen interest in the dynamic field of healthcare. With a focus on understanding the intricacies of human biology and disease mechanisms, Greta is driven by a desire to contribute to advancements in medical research and patient care.