Sarcoidosis is a rare condition in which patches of red, swollen tissue (granulomas) form in various parts of the body.

Sarcoidosis affects many organs in the body, with the lungs the most commonly affected. However, it is considered to be a multisystemic condition, as it can affect the skin, eyes, heart, muscles, joints, bones, liver, kidneys and brain. Read more about how these organs can be affected.

Most people with sarcoidosis get better without specific treatment within 12-18 months and go on to lead normal lives. This is because the body's immune system can heal the condition over time.

Sometimes, for reasons that are not understood, the immune system does not heal the granulomas and scar tissue forms (fibrosis). This can result in damage to the affected body part that requires long-term treatment and monitoring.

There are treatments that can help to slow the disease and improve symptoms. However, no treatment is available to cure this condition.

• How many people are affected?

  It is not known for sure how many people have sarcoidosis. This is because many people may not know they have it, and sometimes it can be mistaken for other diseases.

  The number of cases varies from country to country, with around 2-40 people per 100,000 affected.

  Scientists estimate that 344,000 people are diagnosed each year worldwide.

Scientists do not currently know the cause of sarcoidosis, but there is research being carried out to try and answer this question.

What we do know is:

• Sarcoidosis is not infectious (you cannot catch it and you cannot pass it to another person)
• Sarcoidosis is not a form of cancer
• Sarcoidosis does run in families, but there is only a 5-10% chance someone else in your family will have the condition.

• Who does it affect?

  Sarcoidosis can affect people of any age but it is more common in young adults and is slightly more common in women.

  It is also found more commonly in Afro-Caribbean, Irish and scandinavian people.
  

Diagnosing sarcoidosis can be difficult. Symptoms are very varied and no single test gives a definite diagnosis for this condition.

• Most common symptoms

  • Dry cough
  • Shortness of breath
  • Chest pain
  • Fatigue
  • A flu-like illness with fever, tiredness and joint pains
  • A painful red rash usually occurring on the arms or legs
  • Eye irritation and visual problems
  • Swollen glands, which can be felt in the neck or around the face
  • Difficulties in the ability to concentrate and remember facts

It may take a long time for doctors to make a diagnosis as they must rule out other conditions that look like sarcoidosis, and no two people will present with the same combination of symptoms.

• Usual tests for sarcoidosis

  Testing for sarcoidosis usually includes:

  • A chest X-ray to find out whether the lungs and lymph glands (part of the immune system) are affected.
    
  • Blood tests, including liver and kidney function, calcium and other blood values of the immune system. This can include an ACE level (Angiotensin Converting Enzyme) which may be higher in someone with sarcoidosis.
    
  • Tests to find out how severe the disease is, and which parts of the body are affected, including: heart tracing (ECG), lung function test (spirometry), eye test.

  However, a normal ACE or chest x-ray does not rule out sarcoidosis, while an elevated ACE level does not diagnose sarcoidosis.

• Extra tests

  Doctors may decide to do extra tests depending on your symptoms. This could include:

  • laboratory tests,
  • urine tests,
  • a cardiac workup (MR of the heart)
  • a brain scan (MRI) or,
  • a chest scan (CT).

  Often, doctors need tissue samples or biopsies to confirm the diagnosis. These are usually taken from the glands in the lung, lung tissue, glands in the neck or chest, or from the skin. If a biopsy is needed it will usually be done under local anaesthetic.

  
  

Most people who are diagnosed with sarcoidosis get better without specific treatment and go on to lead normal lives, but sometimes with damage to affected organs. Around 1 in 4 people will have long-term chronic symptoms that require ongoing treatment.

Sarcoidosis in children is extremely rare. The actual number of children with sarcoidosis is hard to assess due to the lack of an international systematic reporting system, but it has been estimated at approximately 0.4 to 1 per 100,000 children. Sarcoidosis has to be distinguished from Blau syndrome, which is another granulomatous condition that affectschildren.

Children of all ages can be affected by sarcoidosis, with the mean age at diagnosis being 11 to 13 years-old with equal numbers in both male and females. Only 3 studies have been published to date, two of them reporting a greater number of black children diagnosed with sarcoidosis in more than two thirds of cases.

• Causes

  The causes of childhood sarcoidosis, as in adult sarcoidosis, remain unknown. The current hypothesis involves the combination of 2 complementary factors: a genetic predisposition, and an exposure to an organic or a mineral antigen (a substance that triggers the immune system to produce antibodies against it) . Research studies are ongoing to test these hypotheses.

• Symptoms and diagnosis

  Children with sarcoidosis usually have the following general symptoms:

  • Prolonged or recurrent fever
  • Marked fatigue
  • Weight loss or lack of weight gain

  All organs may be affected, and children usually have three to four affected organs when diagnosed. The lungs are often involved and respiratory symptoms may also be present such as:

  • Dry cough
  • Breathlessness (dyspnoea) or rapid breathing (tachypnoea)
  • Chest pain

  Non-respiratory symptoms are also often present (see list below) and a full clinical examination is required:

  • A decrease in visual acuity (measure of the ability to distinguish shapes and details of objects), eye pain or a red eye
  • Peripheral lymph nodes
  • Enlarged liver or spleen, abdominal pain
  • Skin disorders
  • Joint pains

  Testing for childhood sarcoidosis should be extensive. In most centres, a biopsy of an affected organ is required to assess the diagnosis and to exclude other conditions, especially infections or immune deficiencies. The tests include:

  • Blood tests including inflammation tests, calcium, liver and kidney function, immune tests and Angiotensin Converting Enzyme (ACE) which may be raised. A blood test for genetic testing (to be used for research purposes) may be proposed to the child and their parents/caregivers.
  • A chest X-ray and a high-resolution CT-scan to search for thoracic lymphadenopathies (enlarged lymph nodes in the chest), interstitial lung disease and/or signs of fibrosis (damaged tissue)
  • A lung bronchoscopy with bronchoalveolar lavage (a procedure to collect a sample from the lungs for testing) to search for a lung inflammation
  • Cardiac explorations (heart tracing), echocardiography
  • Lung function tests (in older children)
  • Eye examination
  • Biopsy of affected organs: swollen glands, liver, skin, lymph nodes, or lung if needed.

• Treatment

  Unlike sarcoidosis in adults, sarcoidosis in children is often an extensive and symptomatic disease at diagnosis, affecting the general condition of the child, but also one or more organs. As a result, most children will require treatment.

  Corticosteroids (prednisolone and prednisone) are the most common drugs used for sarcoidosis and are usually highly effective. They can be given intravenously (through a vein) orally, or both, depending on the diagnosis. The length of the treatment is extremely variable in children and depends on the initial severity and how the condition progresses. Sarcoidosis can last for a few months to years. Steroids are usually well tolerated in children although there may be side-effects which will be closely monitored e.g. hypertension, hyperglycemia, weight gain, osteoporosis, immune deficiency. As the symptoms decrease or disappear, the use of steroids is usually reduced very slowly (over months) to avoid any disease relapse.

  On rare occasions, other immunosuppressive drugs may be proposed.
  

• How does childhood sarcoidosis progress?

  There is very little research on this and the progression of sarcoidosis in children can vary greatly from a quick and stable recovery with no after effects to multiple relapses (return of symptoms) over time. It seems that around half of children with sarcoidosis require no further treatment in adulthood.

  In all cases, a child with sarcoidosis will need long-term follow-up in a specialised center, and a transition of care to an adult center, even if asymptomatic (showing no symptoms) for years.

• Video Q&A with Dr Nadia Nathan

  Watch this video Q&A with Dr Nadia Nathan which was filmed for use by SarcoidosisUK and is used with their permission: