Sarcoidosis Causes

The specific cause of sarcoidosis is not known, although there are certain factors that have been associated with an increased risk of suffering from the condition. These include family history, triggers and dysregulation of the immune system.

As a general rule, it is believed that some individuals are genetically susceptible to sarcoidosis, and if they come into contact with certain environmental factors or triggers, they are likely to experience symptoms of the condition.

The Immune System

The immune system plays a central role in the development of the nodules that characterize sarcoidosis and is thought to be overactive in patients with the condition.

Normally, when any foreign body enters the body of an individual, the immune system is responsible for eliminating the infection by releasing white blood cells. This leads to an inflammatory process, involving swelling and redness in the area that is part of the body’s usual response to infection. These symptoms tend to fade away when the infection clears.

However, in some cases the immune system can continue to be activated, even in the absence of a foreign body or infection. Autoimmunity refers to when the immune system identifies normal cells in the body as foreign and activates the inflammatory response to eliminate normal cells in the body. This is thought to be the main driving factor in sarcoidosis and results in the formation of granulomas in various organs of the body.

Immunity-Related Conditions

As a result of the likely involvement of the immune system in the development of sarcoidosis, there are several health conditions with autoimmune characteristics that are closely linked.

These autoimmune conditions include conditions such as rheumatoid arthritis and lupus. Similarly to sarcoidosis, these conditions involve inflammation of specific areas of the body and lead to symptoms as a result of the swelling.

Genetic Link

It has been observed that sarcoidosis often tends to affect several members in one family, suggesting that there may be a genetic link that increases the risk of the condition. However, there is no sound scientific evidence to support this notion and the genetic pattern of inheritance has not been established.

An alternative reasoning for the pattern of families being affected by sarcoidosis could lie in the communicable nature of a condition. This is not the case for sarcoidosis, however, and it cannot be passed on from one infected person to another. This also supports the idea of a genetic factor at play, although further research is required to confirm this and identify causative genes.

Environmental Factors

Certain triggers are considered to be important for the initiation of granuloma development and successive symptoms. There are several different trigger that may lead to the condition, including:

• Bacteria
• Viruses
• Dust
• Chemicals

These triggers may become apparent in certain environmental or occupational settings. However, not everybody responds in the same way when exposed to environmental triggers, which suggests there is an additional factor that leads to someone suffering from the condition.

Current researchers believe that individuals may be susceptible to environmental triggers due to inherited genetic mutations. This then leads to increases sensitivity when the individual is exposed to irritants and, consequently, the development of sarcoidosis.

References

• http://www.nhs.uk/conditions/sarcoidosis/Pages/Introduction.aspx
• http://www.nhlbi.nih.gov/health/health-topics/topics/sarc/causes
• https://www.ncbi.nlm.nih.gov/pubmed/17684288

Further Reading

• All Sarcoidosis Content
• Sarcoidosis – What is Sarcoidosis?
• Sarcoidosis Diagnosis
• Sarcoidosis Treatment
• Sarcoidosis Prognosis

Written by

Susan Chow

Susan holds a Ph.D in cell and molecular biology from Dartmouth College in the United States and is also a certified editor in the life sciences (ELS). She worked in a diabetes research lab for many years before becoming a medical and scientific writer. Susan loves to write about all aspects of science and medicine but is particularly passionate about sharing advances in cancer therapies. Outside of work, Susan enjoys reading, spending time at the lake, and watching her sons play sports.