Sarcoidosis is a disease characterized by the development and growth of tiny clumps of inflammatory cells in different areas of your body. Sarcoidosis can affect virtually any organ, but most commonly it affects your lungs, lymph nodes, eyes and skin. Doctors believe sarcoidosis results from an abnormal immune response. The course of the disease varies from person to person. It often goes away on its own, but in some people symptoms of sarcoidosis may last a lifetime. If you have minor symptoms of sarcoidosis, you may only need to be monitored until the condition improves. But if symptoms bother you or put vital organs at risk, treatment with anti-inflammatory medications can help.

Complications of Sarcoidosis

In about two-thirds of people with sarcoidosis, the condition resolves with no lasting consequences. But in some people, sarcoidosis can become chronic and lead to 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 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 can affect your skin. One common complication is a condition called erythema nodosum, which is characterized by tender, red bumps that occur primarily on your shins. The bumps 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 of your elbows, ankles, wrists and hands. Generally, erythema nodosum is temporary.
• Nervous system problems. A small percentage of people with sarcoidosis develop problems related to the central nervous system when granulomas form in the brain and spinal cord. Inflammation in the facial nerves can cause facial paralysis.
• Fertility problems. In men, sarcoidosis can affect the testes and possibly cause infertility. 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.

In a few cases, sarcoidosis can be fatal. Death usually occurs as a result of progressive scarring of the lungs and respiratory failure, or as the result of a heart problem, which may lead to sudden death.

Causes of Sarcoidosis

• 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, when you breathe.
• It's also possible that some people have a genetic predisposition to developing sarcoidosis, which, when combined with an environmental trigger, produces the disease. 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, distinct areas of inflammation called granulomas.
• As the disease progresses, granulomas can damage healthy tissue and cause scarring (fibrosis). For example, fibrosis may occur in the tissue between the air sacs in your lungs, stiffening your lungs and reducing the amount of air your lungs can hold.

Signs & Symptoms of Sarcoidosis

Signs and symptoms of sarcoidosis tend to vary, depending on which organs are affected and how long you've had the disease. Some cases cause few, if any, symptoms, and as a result the disease may not be discovered until you have a chest X-ray for other reasons.

In general, sarcoidosis symptoms include:

• Persistent cough
• Shortness of breath
• A vague feeling of discomfort and fatigue
• Fever
• Weight loss
• Small red bumps on your face, arms or buttocks
• Red, watery eyes
• Arthritis in your ankles, elbows, wrists and hands, commonly associated with bumps in the skin over your shins (erythema nodosum)

Sometimes sarcoidosis develops gradually and produces signs and symptoms that last for years. Or it may appear suddenly and then disappear just as quickly.

Diagnosis of Sarcoidosis

Few symptoms early on

Sarcoidosis produces few signs and symptoms in its early stages. In some cases, sarcoidosis is diagnosed incidentally based on an X-ray that was taken for other reasons.

When signs and symptoms 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 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.

Commonly used tests

Your doctor will likely use a number of tests to help determine if you have sarcoidosis, how severe it may be and the extent of your treatment. Tests may include:

• Physical exam. Your doctor will likely check for signs of sarcoidosis, such as bumps on your skin, enlarged lymph nodes and redness in your eyes. He or she may also listen for abnormal sounds in your lungs and heart.
• Chest X-ray. Initially, your doctor is likely to order a chest X-ray to check for granulomas or enlarged lymph nodes. Most people with sarcoidosis have an abnormal X-ray. Depending on the results, you may then have one or more follow-up tests.
• 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 granulomas typical of sarcoidosis (noncaseating granulomas) 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 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 also can produce granulomas.
• Mediastinoscopy. In some cases, such as if a bronchoscopy test yields no information, your doctor may request a biopsy of lymph nodes from the space between your lungs (mediastinum). 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 CT scan. A surgeon usually does this procedure using one or more small incisions. Risks of the procedure are small but 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.
• Electrocardiogram (ECG). An electrocardiogram can tell your doctor how well your heart is functioning and whether it may be affected by sarcoidosis. During an ECG, sensors (electrodes) that can detect the electrical activity of your heart are attached to your chest and sometimes to your limbs. An ECG measures the timing and duration of each electrical phase in your heartbeat.

Staging

You may hear your doctor talk about the stage of the disease in your lungs. Staging is usually based on the results of your chest X-rays.

• Stage 0 stands for a normal chest X-ray.
• Stage I involves enlarged lymph nodes only. The lungs themselves look normal.
• Stage II describes enlarged lymph nodes plus abnormalities in the lung tissue.
• Stage III indicates involvement of the lungs only with normal-sized lymph nodes.
• Stage IV involves scarring of lung tissue (pulmonary fibrosis).

All stages require close follow-up, even if not treated at the time. You can have involvement of your liver, skin, heart, eyes or other organs at any stage, even Stage 0.

Treatments of Sarcoidosis

You may not need treatment for sarcoidosis if you don't have any signs and symptoms or if they aren't bothering you. 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 if the inflammation hasn't improved or has progressed.

On the other hand, treatment with medications is usually recommended if your heart, eyes, kidneys or central nervous system is involved, as related complications can be serious.

Corticosteroid treatment

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, using as low a dose as possible while still controlling the disease. For a small percentage 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.

Other drugs

If you aren't able to tolerate steroid treatment, your doctor may recommend treatment with drugs that help reduce inflammation by suppressing your immune system. Options may include methotrexate or azathioprine (Imuran). But these drugs are powerful, as well, and carry their own risks, such as making you more vulnerable to infections.

The antimalarial drug, hydroxychloroquine (Plaquenil), may be helpful for skin disease, nervous system involvement and elevated blood-calcium levels.

Your doctor can help you decide on the best sarcoidosis treatment. This usually involves weighing the risks and benefits of medications such as corticosteroids and immunosuppressants against the discomfort and risks of leaving the disease untreated.

When to seek Medical Advice

You may not realize you have sarcoidosis, especially early in the course of the illness. 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.