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What is sarcoidosis? Here's everything you need to know about this rare disease.

March 24, 2022 Posted in: Blogs , English


According to research, sarcoidosis is considered among the rarest diseases in the United States, with fewer than 200,000 cases per year. Its causes remain unknown, and the symptoms can range from mild to life-threatening. Here are the most asked questions about sarcoidosis:

  • What exactly is sarcoidosis?
  • What are the different types of sarcoidosis?
  • How is sarcoidosis diagnosed?
  • Is sarcoidosis hereditary?
  • What is the life expectancy of a person with sarcoidosis?

Keep on reading to find out the answers to each of these questions.

What is sarcoidosis?

Sarcoidosis is a rare disease where granulomas grow on parts of the body. They typically appear on the lungs and lymph nodes but can affect the heart, eyes, skin, brain, and other organs. 

What are granulomas? These are tiny collections of inflammatory cells that appear as small, inflamed areas on the body. They are commonly seen in the lungs but can occur elsewhere in the body.

The exact cause of sarcoidosis is unknown, but it is believed to result from the immune system reacting to an unknown substance. Anyone can develop sarcoidosis, but the most common risk factors include:

  • Race. People of Northern European and African descent have higher incidence rates of sarcoidosis, with African Americans more likely to develop it in other organs besides the lungs.
  • Family history. Those with sarcoidosis in their family history are more likely to develop the disease.
  • Age and sex. Sarcoidosis is prevalent among patients between 20 and 60 years of age. Women are also slightly more susceptible

What is sarcoidosis of the lungs?

Also known as pulmonary sarcoidosis, this is the most common form of the disease. Granulomas form small lumps in the lungs and can affect how they work. Over time, these lumps can become stiff scars called pulmonary fibrosis.

What is pulmonary fibrosis? A lung condition in which lung tissue becomes thick or scarred. This changes the structure of the lungs and affects functions like breathing.

Here are some symptoms of pulmonary sarcoidosis:

  • Persistent dry cough
  • Shortness of breath
  • Wheezing
  • Chest pain
  • Fatigue
  • Fever
  • Swollen lymph nodes

What is sarcoidosis of the brain?

Also called neurosarcoidosis, this form of the disease is a long-term condition in which the central nervous system is inflamed. This inflammation damages the myelin, which protects nerve fibers, resulting in the disruption of nerve impulse flow from the central nervous system. This can cause a reduction in body functions and most commonly affects facial and cranial nerves, the pituitary gland, and the hypothalamus.

Symptoms of neurosarcoidosis are said to be similar to multiple sclerosis:

  • Change in menstrual periods for women
  • Excessive urination and thirst
  • Confusion or disorientation
  • Vertigo
  • Hearing loss
  • Loss of sense of smell or taste
  • Seizures
  • Speech impairment
  • Double vision

What is sarcoidosis of the skin?

Cutaneous sarcoidosis occurs in 20 to 30 percent of patients with sarcoidosis. While many types of nonspecific skin lesions can form without granulomas, sarcoidosis of the skin depends on location and appearance. These often show up as the following symptoms:

  • Painful red lumps, typically on the arms or lower legs
  • Joint pain
  • Fatigue
  • Fever
  • Hair loss
  • Scars or tattoos that become inflamed

What is sarcoidosis of the eyes?

When granulomas affect the eyes or their surrounding structures, it is called ocular sarcoidosis. The most common form is uveitis, which involves the inflammation of the iris and its surrounding tissues. It can cause vision abnormalities like floaters and serious complications like vision loss if left untreated.

Symptoms of ocular sarcoidosis include:

  • Dry eyes
  • Itching
  • Burning or pain
  • Eye discharge
  • Redness
  • Blurred vision
  • Moderate to severe redness
  • Light sensitivity

What is sarcoidosis of the heart?

When sarcoidosis appears on the heart, it is called cardiac sarcoidosis. It occurs in about one-third of all sarcoidosis patients, five percent of whom will experience symptoms. This type of sarcoidosis can be dangerous when the granulomas disrupt electrical signals and cause arrhythmia and palpitations. This can even lead to heart failure.

Symptoms of cardiac sarcoidosis include:

  • Chest pain
  • Irregular or fluttering heartbeats
  • Swelling caused by fluid retention
  • Fatigue
  • Syncope, or fainting

How is sarcoidosis diagnosed?

Because sarcoidosis can have many symptoms similar to other conditions, doctors perform a diagnosis of exclusion. This means doctors will need to rule out other possible diseases before diagnosing sarcoidosis. There is no single test to diagnose sarcoidosis since there are many types, but here are the most common tests doctors use:

  • Chest x-ray. A painless diagnostic test to check lungs and airways.
  • CT scans. Sectional pictures of the body can help scan for lung, heart, and other types of sarcoidosis.
  • Lung function tests. This involves breathing into a mouthpiece attached to a spirometer, which measures the amount and speed of the air you exhale.
  • Biopsy. Tissue samples are extracted from the affected part of the body and sent to a diagnostic laboratory for analysis.
  • Blood tests. Many patients produce an excess of vitamin D and an angiotensin-converting enzyme, which can be tracked through blood tests.
  • Echocardiogram. A test that uses ultrasound waves to check for abnormalities in the heart.
  • Heart rhythm monitoring. Also called electrocardiography (ECG or EKG), this test helps track heart function.

Is sarcoidosis hereditary?

The risk of sarcoidosis is higher in families with a history of the disease. A study showed that having a first-degree family member puts you at 3.73 times higher risk of developing sarcoidosis, which increases to 4.69 if you have two first-degree relatives who have the disease. The same study also reports a 39% chance of inheriting the disease.

What is the life expectancy of a person with sarcoidosis?

People who develop sarcoidosis go on to live normal lives. A majority of people (around 60%) who develop sarcoidosis recover without needing treatment, 30% may experience it persistently with or without treatment, and only 10% of patients develop damage to organs that can be life-threatening.

Watch the video below about heart transplant patient Karim Rashid and his experience with cardiac sarcoidosis.


Baylor St. Luke’s Medical Center is among three NORD-recognized Rare Disease Centers of Excellence in Texas, which connect you with high-quality care for rare diseases like sarcoidosis. If you think you have symptoms of pulmonary sarcoidosis, talk to a St. Luke's Health pulmonologist, or speak with a cardiologist for cardiac sarcoidosis. Reach out to a Baylor St. Luke’s Medical Group primary care physician if you have other symptoms or risk factors for sarcoidosis of any type. 

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