Sarcoidosis
- Reviewed by Robert H. Shmerling, MD, Senior Faculty Editor, Harvard Health Publishing; Editorial Advisory Board Member, Harvard Health Publishing
What is sarcoidosis?
Sarcoidosis is an illness that causes tiny islands of inflammatory cells to form throughout the body. These microscopic groups of cells are called granulomas. They are especially common in the lungs, lymph nodes, skin, eyes, and liver. The cause of sarcoidosis is unknown.
Sometimes these granulomas cause very little damage, so a person with sarcoidosis does not have any symptoms of illness and may not even know they have it. In other cases, however, the granulomas produce large areas of inflammation and scarring that can interfere with an organ's normal functions. Although most people with sarcoidosis eventually recover, a few develop forms of the illness that are long-lasting (chronic) and get worse with time.
Sarcoidosis can affect almost any organ in the body. But the most common targets are the lung and nearby lymph nodes.
Although doctors do not know the exact cause of sarcoidosis, there is strong evidence that the illness involves an abnormal immune reaction. For example, it is known that the granulomas contain cells from the immune system, particularly a type called helper-inducer T cells. Some experts believe that the abnormal immune reaction of sarcoidosis may be triggered by an infection. Others suspect that the illness may follow exposure to an allergen (allergy-producing agent) in the environment. In addition, genetic (inherited) factors probably play some role in increasing a person's risk of developing the illness.
In the United States, sarcoidosis affects African Americans three to four times as often as white people. Other groups with a higher than average risk of developing sarcoidosis are Scandinavian, Irish, British, and Asian. In general, women are affected more often than men.
Symptoms of sarcoidosis
Some people with sarcoidosis do not have any symptoms. Others have nonspecific symptoms such as fatigue, weakness, fever, poor appetite, night sweats, joint pain, or aching muscles.
Symptoms vary widely because the disease affects different parts of the body in different people. Among those who see their doctors for specific symptoms, more than 90% have problems involving the lungs. The first signs are usually a dry cough and shortness of breath. Later there may also be wheezing, chest pain, and, rarely, a cough that brings up bloody mucus. In severe cases, lung function may become so poor that you cannot do even simple, routine tasks of daily life.
Other symptoms of sarcoidosis are less common than lung symptoms. They can include:
- Skin symptoms: Sarcoidosis can appear as a collection of tender, red bumps called erythema nodosum. It also can appear as a scaly, purplish discoloration on the nose, cheeks, and ears called lupus pernio. Less often, sarcoidosis causes cysts, pimples, or disfiguring overgrowths of skin that may develop in areas of scars or tattoos.
- Eye symptoms: These include red eyes, eye pain, and sensitivity to light due to a condition called uveitis.
- Heart symptoms: These include irregular heartbeat and shortness of breath.
- Other symptoms: A person may have paralyzed facial muscles, seizures, psychiatric symptoms, swollen salivary glands, or bone pain.
Diagnosing sarcoidosis
In most cases, your doctor will diagnose sarcoidosis based on three factors:
- You have symptoms and physical findings that suggest sarcoidosis.
- Your chest X-ray shows abnormalities (due to enlarged lymph nodes) suggestive of sarcoidosis.
- You have had a biopsy showing abnormalities consistent with sarcoidosis. A biopsy is a small piece of tissue that is removed for laboratory testing. This tissue sample can be taken from your lung, skin, lip, or another inflamed or abnormal area of the body.
It is common for sarcoidosis to be suspected based on abnormal results on a chest x-ray ordered for unrelated reasons. For example, a person who is otherwise healthy may have a chest x-ray as a requirement for his or her work and discover abnormalities that suggest the diagnosis.
Besides the chest x-ray and biopsy mentioned above, additional tests may be recommended. These tests may be performed to rule out other illnesses, or to assess the amount of organ damage caused by sarcoidosis. Some of the most common tests are:
- blood tests to measure levels of calcium or angiotensin-converting enzyme (ACE), both of which may be elevated in people with sarcoidosis
- blood tests to evaluate how well your liver is functioning
- lung function tests to measure how well your lungs are working
- a complete eye examination.
Expected duration of sarcoidosis
Up to a third of people have chronic or progressive forms of the illness. In general, the illness tends to be more severe in African Americans than in white populations.
Preventing sarcoidosis
Because the cause of sarcoidosis is not known, there is no way to prevent it.
Treating sarcoidosis
If your sarcoidosis does not cause any significant symptoms or medical problems, you may not need treatment. Instead, your doctor may decide to simply monitor your condition. As part of this monitoring process, you may have frequent office visits, follow-up chest x-rays, and tests of your blood and lung function.
To treat joint pain, acetaminophen (Tylenol) or nonsteroidal anti-inflammatory drugs (NSAIDs) often are used first before corticosteroids, which tend to have more side effects. If you have signs of moderate or severe lung disease, your doctor may recommend an oral corticosteroid drug, such as prednisone (sold under several brand names) or an inhaled steroid. Corticosteroids also are used to treat sarcoidosis of the joints, skin, nerves, or heart. Corticosteroid eye drops may be used for the eyes.
If corticosteroids are not effective or if they cause serious side effects, other drugs that alter or suppress the immune system may be used. Hydroxychloroquine (Plaquenil) and methotrexate (Folex, Rheumatrex) are among the more common medications in this group.
Other options include leflunomide (Arava), azathioprine, or mycophenolate mofetil. Newer, injectable medications, including infliximab (Remicade) or adalimumab (Humira), may be effective when other treatments have failed. In rare cases, when sarcoidosis causes life-threatening lung disease, a lung transplant may be necessary.
Prognosis
Many people with sarcoidosis have no significant disease activity and require no therapy. For these people, the outlook is excellent. Only a small percentage of people develop permanent or progressive organ damage. Death related to sarcoidosis is rare, and is most commonly due to severe sarcoidosis involving the heart or lungs.
When to call a professional
Call your doctor if you develop any of the symptoms of sarcoidosis, such as shortness of breath or a lingering cough.
Additional info
National Heart, Lung, and Blood Institute (NHLBI)
https://www.nhlbi.nih.gov/
American Academy of Family Physicians (AAFP)
https://www.familydoctor.org/
American Autoimmune Related Diseases Association (AARDA)
https://www.aarda.org/
Arthritis Foundation
https://www.arthritis.org/
American Lung Association
http://www.lung.org/
About the Reviewer
Robert H. Shmerling, MD, Senior Faculty Editor, Harvard Health Publishing; Editorial Advisory Board Member, Harvard Health Publishing
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