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. 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 target is the lung.
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 3 to 4 times as often as white people. Other groups with a higher risk of developing sarcoidosis are Scandinavians, Irish, British and Japanese. In general, women are affected more often than men. About 75% of all those affected are younger than age 40.
Some people with sarcoidosis do not have any symptoms. Others simply feel tired and weak. Still others have nonspecific symptoms, such as 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 more 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. Rarely, 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. In many cases, the disfiguring overgrowths develop in areas of scars or tattoos.
- Eye symptoms. These include red eyes, eye pain and sensitivity to light.
- Heart symptoms. These include irregular heartbeat and heart failure.
- Other symptoms. A person may have paralyzed facial muscles, seizures, psychiatric symptoms, swollen salivary glands or bone pain.
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 abnormal areas that are consistent with sarcoidosis.
- You have had a biopsy done, and it shows signs of 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 needed. These tests may be done 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, which may be high in people with sarcoidosis
- Blood tests to evaluate how well your liver is functioning
- Lung function tests to measure how well you breathe
- A complete eye examination
Only a small percentage 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.
Because the cause of sarcoidosis is not known, there is no way to prevent it.
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 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 a corticosteroid drug, such as prednisone (sold under several brand names). 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 (Araya), cyclophosphamide or azathioprine. 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.
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.
Call your doctor if you develop any of the symptoms of sarcoidosis. In particular, contact your doctor if you have shortness of breath or a lingering cough.
National Heart, Lung, and Blood Institute (NHLBI)
P.O. Box 30105
Bethesda, MD 20824-0105
American Academy of Family Physicians (AAFP)
11400 Tomahawk Creek Parkway
Leawood, KS 66211-2672
American Autoimmune Related Diseases Association (AARDA)
22100 Gratiot Ave.
East Detroit, MI 48021
P.O. Box 7669
Atlanta, GA 30357-0669
American Lung Association
1301 Pennsylvania Ave., NW
Washington, DC 20004