Introduction

Sarcoidosis is an inflammatory disease that starts in your lungs, but in time it can affect virtually any organ in your body, including your liver, skin, heart, nervous system and eyes. Some people have signs and symptoms related to a specific organ, such as shortness of breath from lung problems, but others may have only a vague feeling of illness or no signs or symptoms at all.

Although anyone can develop sarcoidosis, the disease mainly affects adults between the ages of 20 and 40. People of Scandinavian descent and black Americans are particularly at risk. Blacks are also more likely to have severe, chronic symptoms than are whites.

Doctors believe sarcoidosis results from an abnormal immune response. But just what triggers this response isn't known. Doctors do know that sarcoidosis often goes away on its own without treatment — usually within two to three years. Some people may have symptoms for a lifetime, however. And in rare cases sarcoidosis can be fatal.

If you have no signs or symptoms of sarcoidosis or only minor ones, a wait-and-see approach may be appropriate. Treatment for severe cases of sarcoidosis is usually with strong anti-inflammatory medications.

Signs and symptoms

Sometimes sarcoidosis develops gradually and produces signs and symptoms that last for years. Or it may appear suddenly and then disappear just as quickly. In either case, signs and symptoms can vary, depending on which organs are affected and how long you've had the disease.

Sarcoidosis that affects only your lungs, for example, may cause few, if any, symptoms. In fact, you may not know you have the disease until it shows up on a routine chest X-ray. More advanced lung disease may cause shortness of breath (dyspnea) and a cough that won't go away.

Other signs and symptoms of sarcoidosis include:

• A vague feeling of discomfort and fatigue
• Fever
• Weight loss
• Small red bumps on your face, arms or buttocks, a condition more common in blacks than in whites
• Red, watery eyes
• Arthritis in your ankles, elbows, wrists and hands, commonly associated with bumps in the skin over your shins (erythema nodosum)

Causes

Doctors don't know the exact cause of sarcoidosis, although they think it may occur when your immune system overreacts to an unknown toxin, drug or pathogen that enters your body through your airways.

Some experts speculate that the causative agent may be a nontuberculous mycobacterium, a noncontagious member of the family of bacteria that cause tuberculosis. In a small portion of people, sarcoidosis may have a genetic component. Studies are ongoing to investigate the genetic and environmental components of this disease.

Normally, your immune system helps protect your body from foreign substances and invading microorganisms, such as bacteria and viruses. But in sarcoidosis, T-helper lymphocytes — white blood cells that play a key role in your immune response — seem to respond too strongly to a perceived threat. This triggers small areas of inflammation called granulomas.

As the disease progresses, granulomas and scarring (fibrosis) may occur in the tissue between the air sacs, stiffening your lungs and reducing the amount of air your lungs can hold.

Risk factors

Anyone, of any race or age, can develop sarcoidosis. But the following factors are more commonly associated with the disease:

• Race. Black Americans are far more likely to develop sarcoidosis than are white Americans. And although sarcoidosis affects white men and women about equally, black women get the disease twice as often as black men do.
• Ethnicity. People of Scandinavian, German or Irish descent have an increased risk.
• Age. Sarcoidosis normally occurs between the ages of 20 and 40. It rarely affects children, but can occur in adults older than 50.

When to seek medical advice

You may not realize you have sarcoidosis, especially early in the disease. But if you're tired, have a fever, have lost weight, have shortness of breath and a cough that persists for weeks or months, or have raised skin eruptions and joint pain (arthralgia), see your doctor — these signs and symptoms may indicate sarcoidosis.

Screening and diagnosis

Sarcoidosis produces few signs and symptoms in its early stages, and when they do occur, they often resemble those of other illnesses. For that reason, your doctor will diagnose sarcoidosis only after ruling out diseases with similar features, such as lymph cancer (lymphoma), tuberculosis, rheumatoid arthritis, rheumatic fever and fungal infections.

Even then, doctors can miss sarcoidosis. In the majority of cases, undiagnosed sarcoidosis disappears spontaneously, but a few people go on to develop more severe signs and symptoms — usually over a period of years.

No single noninvasive test can positively identify sarcoidosis, but initially, your doctor is likely to order a chest X-ray. Depending on the results, you may then have one or more of the following:

• Lung function tests. Noninvasive pulmonary function tests measure how much air your lungs can hold and the flow of air in and out of your lungs. They can also measure the amount of gases exchanged across the membrane between your lung wall and capillary membrane. During the tests, you're usually asked to blow into a simple instrument called a spirometer. You're most likely to have pulmonary function tests if you're short of breath or a chest X-ray shows changes in your lungs.
• Blood tests. These are used to check your liver function and the amount of calcium in your blood. For reasons that aren't clear, some people with sarcoidosis have higher than normal blood-calcium levels. Blood tests can also measure a substance called angiotensin-converting enzyme (ACE). Many — but not all — people with sarcoidosis have high levels of ACE, which is produced by the cells that make up granulomas. High ACE levels can also result from other illnesses.
• Bronchoscopy. In this procedure, your doctor uses a thin, flexible tube (bronchoscope) to examine the inside of your air passages and to take a small tissue sample (biopsy) for laboratory analysis. The sample can tell your doctor whether noncaseating granulomas — microscopic changes in tissue that occur in sarcoidosis — have formed in your lungs.
• Tissue sample. If parts of your body other than your lungs appear to be affected — your skin, lymph nodes or the outer membrane (conjunctiva) of your eye — your doctor is likely to arrange for a specialist to take a tissue sample (biopsy) from these areas. The samples are then examined for noncaseating granulomas. Because these granulomas can result from a number of conditions, their presence alone can't confirm a diagnosis of sarcoidosis. Other subtle infections can produce granulomas.
• Mediastinoscopy. In this procedure, your surgeon removes a sample of lymph nodes from the space between your lungs (mediastinum) using one or more small incisions. If you have sarcoidosis, the disease is likely to have spread to the lymph nodes in your chest cavity even if the nodes aren't enlarged on a chest X-ray or computerized tomography scan. Risks of the procedure include bleeding, temporary hoarseness and reaction to the anesthetic.
• Slit-lamp examination. In this exam, your doctor uses a high-intensity lamp to examine the inside of your eyes for damage from sarcoidosis.

Complications

Sarcoidosis can lead to a number of complications, including:

• Lung scarring. Untreated pulmonary sarcoidosis can lead to irreversible scarring (fibrosis) of the tissue between the air sacs in your lungs, making it extremely difficult to breathe.
• Eye disease. Some people with sarcoidosis develop eye problems. Inflammation can affect almost any part of your eye and usually causes watering and redness. In a few cases, sarcoidosis can lead to blindness or serious eye diseases, such as cataracts and glaucoma.
• Skin disease. Sarcoidosis affects the skin in some people with the disease, particularly blacks. One common complication is a condition called erythema nodosum, which is characterized by red bumps that occur primarily on your shins. The bumps are usually peanut-sized and can range in number from just a few to more than 20 on each leg. Erythema nodosum can also be associated with aching or swelling in your legs and may be accompanied by arthritis in your elbows, ankles, wrists and hands.
• Nervous system problems. A small percent of people with sarcoidosis develop neurological problems when granulomas form in the brain and spinal cord. Inflammation in the facial nerves can cause facial paralysis.
• Fertility problems. Severe sarcoidosis may make it difficult for some women to become pregnant, but many women with the disease give birth to healthy children. If you're planning a pregnancy, talk to your doctor.
• Heart and liver problems. Sarcoidosis that affects your heart can cause a number of complications, including an irregular heart rhythm (arrhythmia) and a weak heart muscle (cardiomyopathy). Granulomas that form in your liver can affect its ability to function.

Treatment

You may not need treatment if sarcoidosis is affecting only your lungs and nearby lymph nodes. Because sarcoidosis often disappears on its own at this stage, your doctor is likely just to monitor you closely.

When chest X-rays reveal more widespread areas of lung inflammation, your doctor may monitor the disease for three to 12 months and begin treatment only if the inflammation hasn't improved or has progressed.

On the other hand, treatment with medications is usually recommended if your heart, eyes or central nervous system is involved or if your blood-calcium level is elevated.

Powerful anti-inflammatory drugs

Doctors generally use the corticosteroid drug prednisone to treat sarcoidosis. Corticosteroids are powerful anti-inflammatory drugs that mimic the effects of hormones produced by your adrenal glands. They're not the same as the anabolic steroids used by some athletes to increase strength and muscle mass.

Just how long to continue prednisone is a matter of debate. In some cases, you may take medication for several years, in as low a dose as possible while still controlling the disease. For a small percent of people, symptoms return when the medication is discontinued. In addition, prednisone can cause serious side effects, especially when it's taken long-term. These side effects include:

• Osteoporosis, a disease that causes your bones to become thin and brittle, leading to fractures
• High blood pressure
• Cataracts
• Diabetes
• Increased risk of infection
• Weight gain and redistribution of body fat

Talk to your doctor about the best ways to help prevent or reduce the possibility of side effects. One option is to take prednisone every other day, rather than every day.

Self-care

Many people with sarcoidosis recover completely. Others have only minor symptoms. But a few people have more severe problems, including damage to their lungs or other organs. These suggestions may help make it easier to live with sarcoidosis:

• Protect your lungs. To help keep your lungs healthy, don't smoke, and avoid contact with chemicals, dust and other irritants.
• Get regular checkups. If you've received a diagnosis of sarcoidosis, see your doctor often so that your condition can be monitored.
• Maintain a strong support system. A number of organizations and support groups exist to help people cope with sarcoidosis. You might want to consider joining a sarcoidosis support group to share your experiences, feelings and concerns. Although support groups aren't for everyone, they can be a good source for practical information as well as for encouragement and understanding. Your doctor or local chapter of the American Lung Association can help you find a sarcoidosis support group in your community.

By Mayo Clinic Staff
Jul 13, 2006