Sarcoidosis is a disease that causes your immune system to overreact, which can lead to health issues. It can cause lung damage, skin rashes, and eye disease and can affect other organs of the body.
Doctors don’t know the exact cause of sarcoidosis. Some people appear to have a genetic predisposition to developing the disease, which may be triggered by exposure to specific bacteria, viruses, dust or chemicals. Researchers are still trying to pinpoint the genes and trigger substances associated with sarcoidosis.
Normally, your immune system helps protect your body from foreign substances and invading microorganisms, such as bacteria and viruses. But in sarcoidosis, some immune cells collect in a pattern of inflammation called granulomas. As granulomas build up in an organ, the function of that organ can be affected.
T cells play a central role in the development of sarcoidosis, as they likely propagate an excessive cellular immune reaction. For example, there is an accumulation of CD4 cells accompanied by the release of interleukin (IL)–2 at sites of disease activity. This may manifest clinically by an inverted CD4/CD8 ratio. Pulmonary sarcoidosis is frequently characterized by a CD4+/CD8+ ratio of at least 3.5 in bronchoalveolar lavage fluid (BALF), although up to 40% of the cases present a normal or even decreased ratio, thus limiting its diagnostic value. Increased production of TH1 cytokines, such as interferon, is also a feature.
Moreover, both tumor necrosis factor (TNF) and TNF receptors are increased in this disease. The importance of TNF in propagating inflammation in sarcoidosis has been demonstrated by the efficacy of anti-TNF agents, such as pentoxifylline and infliximab, in treating this disease.
Signs and symptoms of sarcoidosis vary, depending on which organs are affected. Sarcoidosis sometimes develops gradually and produces symptoms that last for years. Other times, symptoms appear suddenly and then disappear just as quickly. Many people with sarcoidosis have no symptoms, so the disease may be discovered only when you have a chest X-ray for another reason.
For many people, sarcoidosis begins with these signs and symptoms:
- Swollen lymph nodes
- Weight loss
Almost everyone who has sarcoidosis eventually experiences lung problems, which may include:
- Persistent dry cough
- Shortness of breath
- Chest pain
As many as 25 percent of people who have sarcoidosis develop skin problems, which may include:
- Rash. A rash of red or reddish-purple bumps, usually located on the shins or ankles, which may be warm and tender to the touch.
- Lesions. Disfiguring skin sores may occur on your nose, cheeks and ears.
- Color change. Areas of skin may get darker or lighter in color.
- Nodules. Growths just under the skin may develop, particularly around scars or tattoos.
Sarcoidosis can affect the eyes without causing any symptoms, so it’s important to have your eyes checked. When eye symptoms do occur, they may include:
- Blurred vision
- Eye pain
- Severe redness
- Sensitivity to light
There is no single way to diagnose sarcoidosis, since all the symptoms and laboratory results can occur in other diseases. For this reason, your doctor will carefully review your medical history and examine you to determine if you have sarcoidosis. The main tools your doctor will use to diagnose sarcoidosis include:
- Chest X-rays to look for cloudiness (pulmonary infiltrates) or swollen lymph nodes (lymphadenopathy).
- CT scan to provide an even more detailed look at the lungs and lymph nodes than provided by a chest X-ray.
- Pulmonary function (breathing) tests to measure how well the lungs are working.
- Bronchoscopy to inspect the bronchial tubes and to extract a biopsy(a small tissue sample) to look for granulomas and to obtain material to rule out infection. Bronchoscopy involves passing a small tube (bronchoscope) down the trachea (windpipe) and into the bronchial tubes (airways) of the lungs.
There’s no cure for sarcoidosis. You may not need treatment if you don’t have significant signs and symptoms of the condition. Sarcoidosis often goes away on its own. But you should be monitored closely with regular chest X-rays and exams of the eyes, skin and any other organ involved.
If organ function is threatened, you will likely be treated with a medication.
- Corticosteroids. These powerful anti-inflammatory drugs are usually the first-line treatment for sarcoidosis. In some cases, corticosteroids can be applied directly to an affected area — via a cream to a skin lesion or with an inhaler to your lungs.
- Anti-rejection medications. These medications reduce inflammation by suppressing your immune system.
- Anti-malarial medications. These medications may be helpful for skin disease, nervous system involvement and elevated blood-calcium levels.
- Tumor necrosis factor-alpha (TNF-alpha) inhibitors. These medications are most commonly used to treat the inflammation associated with rheumatoid arthritis. They can also be helpful in treating sarcoidosis that doesn’t respond to other treatments.
Organ transplant may be considered if sarcoidosis has severely damaged your lungs or liver.