Sarcoidosis is an inflammatory disease that can affect any bodily organ. It is characterized by the growth of tiny inflammatory cells called granulomas or nodules. The most commonly affected body parts are the lungs, lymph nodes, eyes, and skin. However, sarcoidosis can also affect the liver, salivary glands, kidneys, sinuses, heart, muscles and bones, and nervous system. Sarcoidosis may result from the body’s immune system reacting to an unknown substance, such as something inhaled from the air.
While there is currently no cure for sarcoidosis, most affected people only need little to modest treatment. Sarcoidosis often clears up on its own. However, some cases can persist for years and cause organ damage. This is because sarcoidosis causes a heightened immune response, which can damage the body’s own tissues. When granulomas over-accumulate in an organ, they can interfere with the normal organ function.
Causes and Risk Factors
The exact cause of sarcoidosis remains unknown. It can affect people of any race, age, or gender. However, it typically manifests in adults aged 20-40 years. Certain ethnic groups can develop sarcoidosis more frequently.
African Americans are three to four times more likely to develop sarcoidosis than people of European descent.
Women tend to be more at risk than men for developing sarcoidosis.
Whereas African Americans are more prone to developing sarcoidosis in the eyes, the disease can develop as painful skin lumps in Northern Europeans, and tends to affect Japanese people in the eyes and heart.
The symptoms of sarcoidosis can vary from person to person and depend on the organs affected. Ninety percent of patients with sarcoidosis have the disease in their lungs, where it is usually detected in a routine chest X-ray before symptoms develop. Symptoms for sarcoidosis of the lungs include:
Shortness of breath
Chest pain (ranging from vague tightness to severe pain like a heart attack)
Symptoms Based on Affected Organ
Lymph nodes: Sarcoidosis of the lymph nodes can result in granulomas or nodules in the neck, under the chin, arm pits, and groin. When this disease affects the liver, most patients do not report any symptoms and do not require treatment.
Heart: Cardiac sarcoidosis can lead to shortness of breath, swelling in the legs, and heart palpitations.
Skin: Here the disease can result in painful red bumps on the legs, arms, nose, cheeks, lips, or ears. Small brownish and painless skin patches can also appear as a result of sarcoidosis.
Eyes: This disease can also affect the eyes, which can lead to sensitivity to light, burning, itching, tearing, and pain. Chronic inflammation of the eye can lead to glaucoma, cataracts and blindness.
Diagnosis and Treatment
Doctors diagnose sarcoidosis by first reviewing the patient’s medical history and conducting a physical exam. The doctor may ask about any symptoms and whether they have progressed or eased over time. Next, the diagnosis may be confirmed with a chest X-ray, CT scan, or a microscopic examination of the specimens from the affected tissues or organs.
In the case of sarcoidosis of the lungs, additional tests are performed in order to rule out tuberculosis, including:
Pulmonary Function Testing: This is an objective measure of lung function and involves breathing maneuvers that measure volume of air and airflow in the lungs.
High Resolution Computed Tomography: This is a special type of CT scan that provides high-resolution images of the lungs.
Six Minute Walk Testing: This test is an important marker of lung function and evaluates the distance walked and the oxygen saturations achieved while walking.
Bronchoscopy: In this test, a flexible fiber-optic scope is passed into the lungs to obtain fluid and tissue samples to aid in diagnosis.
When sarcoidosis is present in the nervous system (brain and spinal cord), a positron emission tomography (PET) scan or magnetic resonance imaging (MRI) can help isolate the affected tissue or organ.
When the liver and kidneys appear to be affected, blood tests are used to assess kidney and liver function. An eye exam can diagnose vision problems caused by sarcoidosis.
A biopsy from the affected body part, especially the skin, lungs, and lymph nodes, also helps confirm the diagnosis.
While there is no current cure for sarcoidosis, in most cases the granulomas resolve without other complications. When treatment is required, there are several medications available, especially for sarcoidosis of the lungs.
The first line of treatment for sarcoidosis is corticosteroids, such as prednisone. This is a highly effective anti-inflammatory drug. For mild skin lesions, eye inflammation, or cough, topical steroid creams, eye drops and inhalers may be enough to control the sarcoidosis. For more severe symptoms such as shortness of breath, steroid therapy is effective and has a low rate of relapse.
For patients who cannot tolerate steroids, there is a range of other available medications. Drugs such as methotrexate (Trezall®) and azathioprine (Azasan®, Imuran®) suppress the immune system and thereby reduce the formation of granulomas.
Anti-malarial medications can also be prescribed for sarcoidosis of skin and lungs, and colchicine is prescribed for sarcoidosis-related arthritis.
Hydroxychloroquine (Plaquenil®) is useful for skin disease and high blood-calcium levels.
Tumor necrosis factor-alpha inhibitors are usually used to treat rheumatoid arthritis. These medications can also help treat sarcoidosis that has not responded to other interventions.
Surgery in the form of organ transplant may be recommended if sarcoidosis has severely damaged the patient’s lungs, heart or liver.
There is no way to prevent sarcoidosis since the exact cause remains unknown.
“Sarcoidosis”. Mayo Clinic. Retrieved July 2016. http://www.mayoclinic.org/diseases-conditions/sarcoidosis/home/ovc-20177969
“What is sarcoidosis”. Foundation for Sarcoidosis Research. Retrieved July 2016 https://www.stopsarcoidosis.org/awareness/what-is-sarcoidosis/
“Sarcoidosis”. UCSF Health. Retrieved July 2016. https://www.ucsfhealth.org/conditions/sarcoidosis/index.html
Tina is a Life Science Writer for a number of online publications, including Innerbody.com. Her expertise is in conveying complex scientific topics to diverse audiences. Tina earned her PhD in Biochemistry from the University of California, San Francisco and her BS degree in Cell Biology from U.C. Davis. In her spare time, she enjoys drawing science-related cartoons.