What Is Sarcoidosis?

Sarcoidosis is a disease marked by an over-active immune system that leads to the formation of small clumps of inflammatory cells called granulomas in different tissues and organs, affecting how well they work. Over time, granulomas can become calcified or bone-like, and cause permanent damage.

Because it can affect any organ, or multiple organs at the same time, sarcoidosis takes on different forms. In some people, the condition manifests itself as a one-time episode, with inflammation resolving by itself while in others, it may come and go episodically. In others yet, sarcoidosis can be a chronic and ongoing problem. The chronic form of the disease is the most serious and the most likely to damage organs and become resistant to treatment.

Sarcoidosis can be treated with medications but may require a multidisciplinary medical team if multiple organs are affected. In its milder forms, however, the disease may resolve without lasting effects and require only regular monitoring.

What causes sarcoidosis?

The exact cause of sarcoidosis is unknown. Some cases are thought to be triggered by an allergic reaction, an infection, or exposure to chemicals in an otherwise healthy person. That person’s immune system, in reacting to the infection or allergen, begins to inexplicably attack the body’s own tissues and organs. This reaction can run its course, or develop into a chronic condition.

The disease may also have a genetic component, as sarcoidosis can run in families and people of African-American and Northern European descent appear to be more likely to develop this disease than others. This is likely due to a combination of genes that leaves a person more vulnerable to the development of the disease. But the exact genes associated with sarcoidosis are unknown.

What are the symptoms of sarcoidosis?

Because sarcoidosis can attack any organ in the body, it can potentially cause problems in the liver, heart, lungs, gut, bones, muscles, or even the brain. The exact symptoms may vary in type and intensity and may resemble those of other diseases or allergic reactions. The condition can, therefore, be mistaken for a different one.

Different types of sarcoidosis, however, have a few symptoms in common. These shared symptoms can include fever, enlarged lymph nodes, swollen and painful joints (as in the case of arthritis), and pressure-sensitive red bumps on the skin called erythema nodosum.

Sarcoidosis most often affects the lungs, when it is known as pulmonary sarcoidosis. Individuals with this kind of sarcoidosis typically also experience fatigue, shortness of breath, chest pain, feelings of congestion, and wheezing or abnormal breathing.

Some people with sarcoidosis may have mild symptoms that they ignore, or they may not develop any noticeable symptoms. A sudden flare may alert them to the condition, but symptoms usually go away on their own. Others will experience sarcoidosis symptoms for years before these go into remission. About half of these patients enter remission within three years of diagnosis; others within 10 years. A relapse — a resumption of disease activity and symptoms — is possible, but unusual in people in remission for at least one year.

People with chronic sarcoidosis are more likely to have organ damage, with a possibility of permanent damage to, say, the lungs or the heart, and severe and lasting disease symptoms. An estimated 10 to 15 percent of all sarcoidosis patients will develop an advanced and chronic, life-altering form of the disease.

How is sarcoidosis diagnosed?

Symptoms of sarcoidosis may be present but mild and unrecognized for months or years before diagnosis. In most cases, sarcoidosis is not diagnosed until a person experiences severe enough symptoms to consult a doctor. Even then, because symptoms mimic that of other conditions, a definite diagnosis can take time. People with chronic sarcoidosis often have severe symptoms, and so are more likely to be correctly diagnosed and given necessary treatment.

Routine blood and lung function tests may be used to diagnose sarcoidosis. The low calcium levels that some sarcoidosis patients experience can be easily detected in a blood test. These tests can also show how well the liver and kidneys are working. Basic exams, like eye examinations, may also be requested.

If a patient complains of shortness of breath or a chronic cough, a chest X-ray may be performed. In sarcoidosis, the X-ray will show the distinctive granulomas as dark spots on the lungs. Nearby lymph nodes may also be unusually enlarged. If doctors suspect other organs to be affected by sarcoidosis, they may examine and request a scan of those organs. A lung biopsy may be performed to confirm suspected pulmonary sarcoidosis.

How is sarcoidosis treated?

There is currently no known cure for sarcoidosis, but various treatments can help to ease its symptoms.

For episodic or short-term cases, lifestyle choices such as regular exercise and a healthy diet may suffice and non-steroidal anti-inflammatory drugs (NSAIDs) may be the only medications needed.

For more severe cases, immune-modulating therapies such as corticosteroids may be needed to relieve the inflammation that is the root cause of sarcoidosis and prevent or lessen damage to organs.


Last updated: Jan. 27, 2020


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