Silicosis
Basics
Description
- Pneumoconiosis (fibrogenic or carcinogenic) caused by inhalation of crystalline silica dust in the form of quartz, cristobalite, or tridymite. Diagnosis is based on history of exposure and radiographic findings (1).
- Classification (1):
- Chronic (classic) silicosis can be simple or complicated and occurs after 10 years of exposure at low concentrations:
- Chronic simple silicosis is asymptomatic and consists of multiple small, round, pulmonary opacities. It is the most common form.
- Chronic complicated silicosis (progressive massive fibrosis) has progressively worsening symptoms and large conglomerate pulmonary opacities.
- Accelerated silicosis develops after 5 to 10 years of heavy exposure and resembles chronic complicated silicosis.
- Acute silicosis (silicoproteinosis) occurs a few weeks to 5 years after massive exposure and is a clinically and histologically distinct form.
- Chronic (classic) silicosis can be simple or complicated and occurs after 10 years of exposure at low concentrations:
- System(s) affected: pulmonary
Epidemiology
Incidence
- 3,600 to 7,300 new cases per year of silicosis have been reported in the United States between 1987 and 1996.
- Rarely seen <50 years of age
- Predominant sex: male > female (secondary to exposure) (1)
Prevalence
2.3 to 4.3 million U.S. workers are exposed to silica; disease is likely underreported (1).
Etiology and Pathophysiology
- Multiple mechanisms proposed, mainly inflammatory with macrophage dysfunction
- Silica is not dissolved in tissue and remains biologically active for long periods.
- Chronic simple silicosis: 10 to 15 years of exposure to silica dust
- Chronic complicated silicosis: 15 to 20 years of exposure
- Accelerated silicosis: 5 to 10 years of heavy exposure
- Acute silicosis: few weeks to 5 years of massive exposure, particularly in sandblasting (2,3)
Genetics
Possible genetic link found between (1):
- Disease severity and TNF-α-238 variant
- Increased risk for silicosis development and TNF-α-308 and IL-1RA+2018 variant, irrespective of disease severity
Risk Factors
Silica is a mineral naturally occurring in rock (especially quartz), sand, concrete, ceramics, brick, and tiles. Occupations at risk (1):
- Metal mining (copper, silver, gold, lead, coal)
- Foundries
- Sandblasting
- Ceramics manufacturing
- Rubber and glass manufacturing
- Granite and sandstone cutting
- Shipyard work
- Highway repair
General Prevention
- Avoid dust exposure.
- Substitute other materials for silica.
- Use respiratory-protective devices for unavoidable exposure.
Commonly Associated Conditions
- Tuberculosis (TB):
- Occurs in 25% of patients
- Malignancy:
- Lung (The US National Institute for Occupational Safety and Health classified crystalline silica as a human carcinogen.)
- Other malignancies, including gastric and esophageal cancers
- Autoimmune/connective tissue disease:
- Rheumatoid arthritis (Caplan syndrome), scleroderma, systemic lupus erythematosus
- Nonmalignant renal disease
- Infections with non-TB mycobacteria
- COPD
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Citation
Domino, Frank J., et al., editors. "Silicosis." 5-Minute Clinical Consult, 33rd ed., Wolters Kluwer, 2025. Medicine Central, im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/116558/all/Silicosis.
Silicosis. In: Domino FJF, Baldor RAR, Golding JJ, et al, eds. 5-Minute Clinical Consult. Wolters Kluwer; 2025. https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/116558/all/Silicosis. Accessed December 13, 2024.
Silicosis. (2025). In Domino, F. J., Baldor, R. A., Golding, J., & Stephens, M. B. (Eds.), 5-Minute Clinical Consult (33rd ed.). Wolters Kluwer. https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/116558/all/Silicosis
Silicosis [Internet]. In: Domino FJF, Baldor RAR, Golding JJ, Stephens MBM, editors. 5-Minute Clinical Consult. Wolters Kluwer; 2025. [cited 2024 December 13]. Available from: https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/116558/all/Silicosis.
* Article titles in AMA citation format should be in sentence-case
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T1 - Silicosis
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ED - Baldor,Robert A,
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ED - Stephens,Mark B,
BT - 5-Minute Clinical Consult, Updating
UR - https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/116558/all/Silicosis
PB - Wolters Kluwer
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DB - Medicine Central
DP - Unbound Medicine
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