Sarcoidosis
Sarcoidosis is a condition where the immune system overreacts and forms tiny lumps called granulomas in various organs of the body, most commonly in the lungs and lymph nodes, though it can affect almost any part of the body including the skin, eyes, heart, and nervous system.
Table of contents
- What is sarcoidosis?
- What causes sarcoidosis?
- Who is affected by sarcoidosis?
- What are the symptoms?
- How is sarcoidosis diagnosed?
- Treatment options
- Living with sarcoidosis
What is sarcoidosis?
Sarcoidosis is a rare inflammatory disease that causes tiny collections of immune system cells to form small, red, and swollen lumps called granulomas in different parts of the body[1]. A granuloma is an area of inflammation made up of a cluster of white blood cells that have been walled off from the rest of the body. These granulomas are surrounded by dense tissue, which makes them feel hard and lumpy[2].
While granulomas can form almost anywhere in the body, they most commonly appear in the lungs and lymph nodes in the chest[1][4]. The disease can also affect the skin, eyes, heart, liver, kidneys, and nervous system. Depending on their location and size, granulomas can cause mild to severe symptoms, or no symptoms at all. In some cases, they can turn into fibrosis, causing permanent scarring of organs[2].
Sarcoidosis is considered a rare disease, with usually fewer than 200,000 cases at any given time in the United States[2]. The course of the disease varies greatly from person to person. For some, sarcoidosis appears only briefly and then goes away on its own without treatment. For others, it may cause long-lasting damage to organs and require ongoing medical care[6].
What causes sarcoidosis?
The exact cause of sarcoidosis remains unknown[1][3]. However, experts believe it likely results from a combination of genetic and environmental factors[1].
Some people appear to have gene changes that make them more likely to develop sarcoidosis. The condition may then be triggered by exposure to certain bacteria, viruses, dust, or chemicals[1]. Studies have found associations with occupational and environmental exposures to substances such as beryllium, dust, insecticides, mold, and other agents[3][4].
When triggered, the immune system overreacts, causing inflammation that forms granulomas[1]. The immune response in sarcoidosis involves specific pathways and chemical messengers including tumor necrosis factor alpha, which plays a fundamental role in the granulomatous inflammatory process[5].
An interesting theory suggests that granulomas persist as long as the body is unable to clear the causative substance. Since almost all cases of sarcoidosis begin with lung involvement and swollen lymph nodes in the chest, inhaled substances are believed to be the likely entry point[5].
Who is affected by sarcoidosis?
While anyone can develop sarcoidosis, certain groups of people are more commonly affected. The disease is more common in Black people than in white people, and it affects females slightly more than males[2].
Most cases are diagnosed in adults between the ages of 25 and 40, though it can occur at any age[2][7]. The disease is rare in childhood[7].
The incidence is about 11 cases per 100,000 in white Americans but 34 cases per 100,000 in African Americans, with a lifetime risk of 2.4 percent in the United States[3]. The disease is more common in Western countries and appears to be more severe in people of African descent living in the United States[5].
While you cannot inherit sarcoidosis directly, you are at higher risk of developing it if you have a first-degree biological relative (parent, child, or sibling) who has the condition[2]. Some cases have been described in more than one family member, usually related to certain genetic markers[3].
What are the symptoms?
The symptoms of sarcoidosis vary widely depending on which organs are affected and how severely they are impacted[1]. Many people with sarcoidosis have no symptoms at all, and the condition is discovered only when a chest X-ray is done for another reason[1].
General symptoms
When symptoms do occur, sarcoidosis often begins with general feelings of being unwell. These can include extreme tiredness, slight fever, swollen lymph nodes (such as in the chest, neck, armpits, or groin), weight loss, and pain and swelling in joints, particularly the ankles[1][2].
Lung symptoms
Since sarcoidosis most often affects the lungs, respiratory symptoms are common. These include shortness of breath, a persistent dry cough, chest pain, and wheezing[2][7].
Skin symptoms
The skin is affected in many people with sarcoidosis. This can cause tender bumps or patches to develop on the skin, particularly on the lower legs and arms. Red, tender bumps on the shins are called erythema nodosum[2][7]. Other skin manifestations include raised, reddish-purple sores or rash across the nose or cheeks called lupus pernio, growths under the skin around scars or tattoos, and light or dark patches of skin[2].
Eye symptoms
Eye involvement can cause blurred vision or loss of vision, eye pain, red or swollen eyes (uveitis or conjunctivitis), and sensitivity to light[2][7].
Heart symptoms
When sarcoidosis affects the heart, symptoms can include chest pain, fluttering heartbeat (palpitations), irregular heartbeat (arrhythmia), heart failure, and shortness of breath[2]. Cardiac involvement occurs in about 5% of all sarcoidosis cases, but studies reveal clinically silent heart involvement in 25% of cases. Heart complications can be serious and account for up to 25% of sarcoidosis-related deaths[11].
Nervous system symptoms
When the nervous system is affected, symptoms may include increased thirst or urination, weak or paralyzed facial muscles (Bell’s palsy), headaches, and seizures[2].
Lofgren’s syndrome
Some people experience a set of symptoms called Lofgren’s syndrome when they first develop sarcoidosis. This usually goes away completely within two years. Symptoms may include swollen lymph nodes, a rash of small bumps called erythema nodosum, blurred vision or eye problems, joint pain or swelling, and fever[4].
How is sarcoidosis diagnosed?
Diagnosing sarcoidosis can be challenging because there is no single test that confirms the condition, and its symptoms can be similar to many other diseases[4][8].
The diagnostic process typically begins with a detailed medical history and physical examination. The healthcare provider will ask about symptoms, lifestyle, and other health conditions. The physical exam may include checking temperature, looking for swollen lymph nodes, spleen, or liver, listening to the chest with a stethoscope, and looking for rashes or sores on the body[4].
Imaging tests
Various imaging tests are commonly used. A chest X-ray can look for abnormalities in the lungs and heart[4][8]. A CT scan of the chest provides more detailed images of the lungs[8]. Other imaging tests may include positron emission tomography (PET) scans or magnetic resonance imaging (MRI) if sarcoidosis may be affecting the heart or central nervous system[8].
Lung function tests
Lung function tests, also called pulmonary function tests, measure how much air you can breathe in and out and how much oxygen your lungs send to your blood[8].
Laboratory tests
Blood and urine tests help check overall health and how well the kidneys and liver are working[8].
Biopsy
A biopsy is often necessary to confirm the diagnosis. This involves taking a small sample of tissue from an affected organ, such as the skin, lymph nodes, or lungs. The sample is examined under a microscope to look for the granulomas characteristic of sarcoidosis and to rule out other diseases that look similar[6][8]. The tissue must show granulomas without necrosis (cell death in the center), and staining for infectious agents like mycobacteria and fungi must be negative[5].
Other specialized tests
Depending on symptoms, additional tests may include eye examinations, heart tests like electrocardiogram (ECG or EKG) and cardiac ultrasound, and other organ-specific assessments[8].
Treatment options
Not everyone with sarcoidosis needs treatment[1][9]. In about 30% of cases, the disease may go away on its own without ever being treated[11]. If symptoms are not bothersome or life-threatening, a doctor may choose to monitor the condition rather than start treatment immediately[12].
Treatment is indicated to manage bothersome symptoms that reduce quality of life and to prevent organ damage[12]. When sarcoidosis affects certain critical organs such as the heart or brain, treatment is usually necessary to prevent severe organ damage or death, even if there are no symptoms[6][12].
Corticosteroids
Taking a corticosteroid medicine, such as prednisone, is the most common way to treat sarcoidosis[6][12]. These drugs work by reducing inflammation caused by the disease[12]. However, long-term use of corticosteroids, especially at high doses, can cause serious side effects such as excessive weight gain, acne, diabetes, high blood pressure, mood swings, cataracts, glaucoma, and weakening of bones (osteoporosis)[12]. Doctors aim to use the lowest dose possible and taper the medication as quickly as feasible, usually within three months[12].
Immunosuppressive medications
If corticosteroids alone are not effective or if high doses are needed for an extended period, immunosuppressive medications such as methotrexate or azathioprine may be added[12][13]. These are considered second-line steroid-sparing medications that may allow the doctor to safely reduce the dose of prednisone while controlling symptoms and preventing further organ damage[12]. Patients taking these medications need regular monitoring with blood tests[12].
Biologic therapies
For patients with severe and treatment-resistant disease, more advanced options include anti-tumor necrosis factor-alpha inhibitors such as infliximab[12][13]. These medications target a specific chemical in the immune system to reduce inflammation and are often given through an infusion into a vein[12].
Other treatments
Some manifestations of sarcoidosis may be treated only locally, such as anterior uveitis or certain skin conditions[11]. Other supportive treatments may include oxygen therapy or pulmonary rehabilitation for lung involvement[9].
The time to see improvement after starting treatment varies from a few weeks to a few months[12]. It is important to take medications as prescribed and report any side effects to the doctor.
Living with sarcoidosis
Even if you do not have symptoms of sarcoidosis, you should see your healthcare provider for ongoing care[15]. Regular monitoring is important to check that the disease is not worsening or damaging organs. For example, routine tests may be needed to ensure the lungs are working well, and regular eye examinations are recommended even without vision problems[6][15].
Understanding remission and flares
If sarcoidosis goes into remission, the doctor may carefully stop treatment. However, monitoring should continue because symptoms can return in what is called a flare. Most flares happen within six months of stopping treatment. The longer you go without symptoms, the less likely you are to have a flare[15].
Lifestyle modifications
Having a healthy lifestyle can help manage symptoms and overall health. Important recommendations include eating a variety of healthy foods such as fruits, vegetables, grains, protein foods, and dairy[6]. Regular physical activity is beneficial even though extreme tiredness can make exercise difficult. Physical activity can improve energy and help with symptoms like shortness of breath and muscle weakness[15].
Because sarcoidosis disrupts the body’s ability to regulate calcium, it may be wise to avoid excessive sun exposure, a diet high in dairy products, or taking vitamin D or calcium supplements unless directed by your doctor[20].
It is essential not to smoke. Smoking can make sarcoidosis worse, and quitting is one of the most important things you can do[6]. You should also avoid dust, smoke, and fumes that can harm the lungs[6].
Managing symptoms and complications
Some people have sarcoidosis that persists or returns for many years after diagnosis. This may be called chronic, severe, advanced, or progressive sarcoidosis[15]. Watch for warning signs of complications that may require emergency medical treatment, such as sudden changes in vision, kidney failure, cardiac arrest, or sudden shortness of breath or muscle weakness[15].
If you think you have symptoms of depression, talk to your doctor. Symptoms include feeling sad or hopeless most of the time, or losing interest in activities that used to make you happy[6].
Support and resources
Many people living with sarcoidosis find it helpful to belong to a support group[20]. As your condition evolves, pay close attention to your body and note any changes. Maintain regular checkups with your healthcare provider, and let them know whenever your symptoms change[20].
The best way to take care of yourself while living with sarcoidosis is to follow your doctor’s recommendations, take medications as directed, and discuss any changes in symptoms with your provider[12].
