Silica is a common, naturally-occurring crystal. It is found in most rock beds. Silica dust forms during mining, quarrying, tunneling, and working with certain metal ores. Silica is a main part of sand, so glass workers and sand-blasters are also exposed to silica.
Three types of silicosis occur:
Chronic silicosis, which results from long-term exposure (more than 20 years) to low amounts of silica dust. The silica dust causes swelling in the lungs and chest lymph nodes. This disease may cause people to have trouble breathing. This is the most common form of silicosis.
Accelerated silicosis, which occurs after exposure to larger amounts of silica over a shorter period of time (5 to 15 years). Swelling in the lungs and symptoms occur faster than in simple silicosis.
Acute silicosis, which results from short-term exposure to very large amounts of silica. The lungs become very inflamed and can fill with fluid, causing severe shortness of breath and a low blood oxygen level.
People who work in jobs where they are exposed to silica dust are at risk. These jobs include:
Road and building construction
Intense exposure to silica can cause disease within a year. But it usually takes at least 10 to 15 years of exposure before symptoms occur. Silicosis has become less common since the Occupational Safety and Health Administration (OSHA) created regulations requiring the use of protective equipment, which limits the amount of silica dust workers inhale.
Shortness of breath
Exams and Tests
Your health care provider will take a medical history. You'll be asked about your jobs (past and present), hobbies, and other activities that may have exposed you to silica. The provider will also do a physical exam.
Tests to confirm the diagnosis and rule out similar diseases include:
There is no specific treatment for silicosis. Removing the source of silica exposure is important to prevent the disease from getting worse. Supportive treatment includes cough medicine, bronchodilators, and oxygen if needed. Antibiotics are prescribed for respiratory infections as needed.
Treatment also includes limiting exposure to irritants and quitting smoking.
People with silicosis are at high risk of developing tuberculosis (TB). Silica is believed to interfere with the body's immune response to the bacteria that cause TB. Skin tests to check for exposure to TB should be done regularly. Those with a positive skin test should be treated with anti-TB drugs. Any change in the appearance of the chest x-ray may be a sign of TB.
People with severe silicosis may need to have a lung transplant.
Joining a support group where you can meet other people with silicosis or related diseases can help you understand your disease and adapt to its treatments.
Outcome varies, depending on the amount of damage to the lungs.
Silicosis can lead to the following health problems:
Denis Hadjiliadis, MD, MHS, Associate Professor of Medicine, Pulmonary, Allergy, and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.